JP7040567B2 - Control device, control method of control device, information processing program, and recording medium - Google Patents

Description

The present invention relates to a control device or the like that outputs a command value calculated from a target trajectory to a servo control system.

Conventionally, the command value generated from the target trajectory is output to the servo control system for each control cycle, and the servo is controlled by considering the response delay time of the servo control system for the control device that controls the servo control system. Attempts to improve the accuracy of control by control systems are known.

For example, Patent Document 1 below discloses a control device that executes the following processing in order to suppress a locus deviation caused by a variation in response delay time between a plurality of axes (a plurality of servomotors). .. That is, a control device that adjusts the command timing to each servo driver according to the response delay time of each servo motor is disclosed.

Japanese Unexamined Patent Publication No. 2017-102616

However, even if the response delay time of the servo control system is taken into consideration, a gap may occur between the position of the servo control system itself and the position of the work whose position is controlled by the servo control system.

One aspect of the present invention realizes high accuracy in position control of the work by considering the deviation between the position of the servo control system itself and the position of the work whose position is controlled by the servo control system. The purpose is.

In order to solve the above problems, the control device according to one aspect of the present invention is a control device that outputs a command value calculated from a target trajectory to the servo control system, and considers the response delay time of the servo control system. Then, from the detection result of the detection device at the detection time, which is the time when the target position calculated from the target trajectory coincides with the detection position, which is the position where the detection device detects the detection target, the position is determined by the servo control system. The first deviation amount calculation unit that calculates the first deviation amount, which is the deviation amount of the position of the work to be controlled from the detection position, the feedback position of the servo control system at the detection time, and the detection time. The second deviation amount calculation unit that calculates the second deviation amount, which is the deviation amount from the target position calculated in consideration of the response delay time, and the target position calculated from the target trajectory are the first. It is provided with a command value generation unit that generates the command value from the corrected target position corrected by the deviation amount and the second deviation amount and the response delay time.

According to the above configuration, the control device may use the servo control system according to the corrected target position obtained by correcting the target position by the first deviation amount and the second deviation amount, and the response delay time. Generate the command value to be output.

Here, when the feedback position and the "target position considering the response delay time of the servo control system" completely match at the detection time, the feedback position is set to the detection position at the detection time. It will be an exact match. Therefore, when the feedback position and the "target position considering the response delay time of the servo control system" completely match at the detection time, the amount of deviation of the work position from the feedback position is determined. It can be specified only from the first deviation amount.

However, in reality, at the detection time, the feedback position and the "target position in consideration of the response delay time of the servo control system" may not completely match.

Therefore, the control device increases the "deviation amount of the position of the work from the feedback position" at the detection time by considering the second deviation amount in addition to the first deviation amount. Specify for accuracy. Then, the control device has the corrected target position corrected by the specified "deviation amount of the work position from the feedback position" and the "target position calculated from the target trajectory", and the servo control system. The command value is generated from the response delay time of.

Therefore, the control device can control the position of the work with high accuracy by considering the deviation between the position of the servo control system (feedback position) and the position of the work whose position is controlled by the servo control system. It has the effect of being able to be transformed.

Further, the control device calculates the first deviation amount from the detection result at the detection time when "the target position calculated in consideration of the response delay time matches the detection position". Therefore, the control device does not need to stop the movement of the work by the servo control system in order to calculate the first deviation amount.

Therefore, the control device can perform high-speed position control on the work at high speed, in other words, can realize high-speed and high-precision position control on the work.

The control device according to one aspect of the present invention is a communication control that communicates the detection instruction time corrected for the detection time with the detection control device that controls the detection operation by the detection device in consideration of the response delay time of the detection device. The detection is specified by the control signal transmitted to the device for each control cycle, and the communication control device is made to execute the output of the detection instruction to the detection control device at the detection instruction time. The detection target may be detected at the time.

According to the above configuration, the control device sets a detection time, which is "a time when the target position calculated from the target trajectory in consideration of the response delay time of the servo control system coincides with the detection position". The detection instruction time, which is the time corrected by the response delay time of the detection device, is calculated. Then, the control device designates the detection instruction time in the control signal output to the communication control device for each control cycle.

The communication control device that received the control signal transmits the detection instruction to the detection control device at the detection instruction time, and the detection control device that receives the detection instruction causes the detection to the detection device. Have the target detected. Therefore, the time at which the detection device detects the detection target is a time delayed from the detection instruction time by the response delay time of the detection device, that is, the detection time.

Here, when the detection device tries to execute the detection without considering the response delay time of the detection device, the detection device executes the detection at the time when the detection device actually executes the detection. It will be delayed by the response delay time of the detection device from the instructed time.

Therefore, the control device calculates the detection instruction time, which is the time obtained by correcting the detection time by the response delay time of the detection device. Then, the control device designates the detection instruction time as the time for instructing the detection device to execute the detection.

Therefore, the control device detects the detection device at the detection time by designating the detection instruction time in consideration of the response delay time of the detection device as the time for instructing the detection device to execute the detection. It has the effect of being able to execute.

Further, the control device specifies the detection instruction time in the control signal transmitted for each control cycle. For example, the control device sets the detection instruction time in a control cycle before the detection instruction time. It is specified in the control signal.

Therefore, by designating the detection instruction time in the control signal, the control device may specify the detection instruction time even when the detection instruction time is not an integral multiple of the control cycle which is the communication cycle with the communication control device. It has the effect of being able to detect the detection target at the detection time.

The control device according to one aspect of the present invention executes communication with the servo control system at each control cycle, and the feedback position of the servo control system at the detection time is set at each control cycle of the servo control system. It may be calculated by the interpolation calculation from the feedback position.

According to the above configuration, the control device calculates "the feedback position of the servo control system at the detection time" from "the feedback position of the servo control system for each control cycle" by interpolation calculation. ..

For example, when n is an "integer of 0 or more" and the detection time is a time between the "n" th control cycle and the "n + 1" th control cycle, the control device is described as follows. "Feedback position of the servo control system at the detection time" is calculated. That is, from the "feedback position in the" n "th control cycle" and the "feedback position in the" n + 1 "th control cycle" of the servo control system, the control device is "the said of the servo control system. "Feedback position at detection time" is calculated.

Therefore, the control device can accurately "at the detection time of the servo control system" even when the detection time is not an integral multiple of the control cycle which is the communication cycle with the servo control system. It has the effect of being able to calculate the "feedback position".

The control device according to one aspect of the present invention may output a command value in consideration of the response delay time of each of the plurality of servo control systems to each of the plurality of servo control systems synchronized with each other.

According to the above configuration, the control device outputs a command value in consideration of the response delay time of each of the plurality of servo control systems to each of the plurality of servo control systems synchronized with each other.

Therefore, the control device has an effect that the plurality of servo control systems can be controlled in a state of being synchronized with each other to realize highly accurate position control of the work.

Regarding the control device according to one aspect of the present invention, the detection device is an image pickup device, and the first deviation amount calculation unit has a reference point corresponding to the detection position in the image pickup image captured by the image pickup device and the image pickup. The first deviation amount may be calculated from the deviation amount from the position of the work in the image.

According to the above configuration, the control device calculates the first deviation amount based on the deviation amount between the reference point (for example, the center position of the captured image) and the position of the work in the captured image. Then, the control device applies to the servo control system by the corrected target position obtained by correcting the target position by the first deviation amount and the second deviation amount and the response delay time of the servo control system. Generate the command value to be output.

Here, there is known an image analysis technique for specifying the position of an image pickup target in a captured image at high speed and with high accuracy.

Therefore, the control device has the effect of being able to realize high-speed and high-precision position control of the work by the first deviation amount calculated from the captured image at high speed and with high accuracy and the second deviation amount. Play.

Further, according to the above configuration, the control device takes into consideration the response delay time of the servo control system, and at the time when the target position calculated from the target trajectory reaches the detection position, the captured image. Is imaged. Therefore, in the captured image, the target position calculated from the target trajectory in consideration of the response delay time of the servo control system and the reference point (for example, the center position of the captured image) coincide with each other.

Here, the "target position in consideration of the response delay time of the servo control system" at the detection time is calculated from the target trajectory in consideration of the response delay time of the servo control system. Therefore, at the detection time, the feedback position and the "target position considering the response delay time of the servo control system" should be sufficiently close to each other. That is, when the feedback position and the position of the work (for example, the center position of the work) are sufficiently close to each other, the position of the work should be sufficiently close to the detection position at the detection time. Therefore, for example, when the center position of the captured image is set as the reference point, the work is arranged substantially in the center of the captured image.

Therefore, the control device can reduce the inspection area for specifying the position of the work (for example, the center position of the work) in the captured image, and can realize high-speed image analysis processing. ..

Further, since the work is arranged substantially in the center of the captured image, the ratio of the captured region of the work to the entire captured image is larger than that of the captured image in which the work is not arranged substantially in the center. It can be made large, that is, the work can be magnified and imaged. Therefore, the control device can perform high-precision image analysis on the captured image captured by enlarging the work.

Therefore, the control device can realize high-speed and high-precision image analysis for the captured image, and by using the result of this image analysis, it is possible to realize high-speed and high-precision position control of the work. Play.

Regarding the control device according to one aspect of the present invention, the servo control system includes a servomotor that drives the axis of a manipulator that can change the position of the work, and a servodriver that controls the servomotor, and the target position. And the feedback position may be the target position and the feedback position of the hand which is the grip portion of the manipulator, respectively.

According to the above configuration, in the control device, the detection time, that is, the target position of the hand calculated from the target trajectory in consideration of the response delay time of the servo control system is set to the detection position. The first deviation amount is calculated from the detection result at the "matching time". Further, the control device has the feedback position of the hand at the detection time and the target position (that is, the target of the hand calculated from the target trajectory in consideration of the response delay time of the servo control system. The second deviation amount is calculated from the position ").

Then, the control device corrects the target position based on the first deviation amount calculated from the detection result and the second deviation amount for the hand at the detection time, and obtains the corrected target position. Generate. The control device generates the command value to be output to the servo control system based on the generated target position after correction and the response delay time of the servo control system.

Therefore, the control device realizes highly accurate position control of the work by the manipulator in consideration of the first deviation amount at the detection time and the second deviation amount for the hand at the detection time. It has the effect of being able to do it.

For the control device according to one aspect of the present invention, the manipulator executes a picking operation and a place operation of the work, and the first deviation amount is the position of the work held by the manipulator from the detection position. It may be a deviation amount.

According to the above configuration, the control device is based on the first deviation amount and the second deviation amount, which are "the deviation amount of the position of the work held by the manipulator from the detection position". The target position is corrected, and the corrected target position is generated. Then, the control device generates the command value to be output to the servo control system based on the corrected target position and the response delay time of the servo control system.

Here, even when the feedback position and the target position calculated in consideration of the response delay time completely match, depending on the state of the work gripped by the manipulator, the said at the detection time. The position of the work deviates from the detection position. For example, when the manipulator grips the work at a position on the right side of the center position of the work, the center position of the work at the detection time shifts to the left side with respect to the detection position. Similarly, when the manipulator grips the work at a position on the left side of the center position of the work, the center position of the work at the detection time shifts to the right side with respect to the detection position.

Further, it is considered that the "deviation between the position of the work and the position of the hand" that occurs during the picking operation is often maintained until the place operation.

Therefore, the control device identifies the "deviation between the position of the work and the position of the hand" that occurs during the picking operation, and considers the specified "deviation between the position of the work and the position of the hand" and considers the work. Control the place position of.

Therefore, the control device has the effect of being able to realize highly accurate position control of the work in consideration of the state of the work held by the manipulator.

For the control device according to one aspect of the present invention, the hand of the manipulator may perform the picking operation by vacuum suction or magnetic suction.

According to the above configuration, the control device is based on the first deviation amount of the work held by the hand using vacuum suction or magnetic suction and the second deviation amount of the manipulator's hand. , The target position is corrected, and the corrected target position is generated. Then, the control device generates the command value to be output to the servo control system based on the corrected target position and the response delay time of the servo control system.

Here, compared to the case where the work is gripped by a two-finger or five-finger type gripper (hand), when the work is gripped by vacuum suction or magnetic suction, the work is displaced from the center position of the work. It is considered that there is a greater possibility that the work will be gripped at a vertical position.

Therefore, in order to control the position of the work held by the manipulator with high accuracy, it is necessary to consider "the deviation between the position of the work and the position of the hand" by using vacuum suction or magnetic suction. Larger when gripped.

Therefore, the control device has an effect that the servo control system including the manipulator that executes the picking operation by vacuum suction or magnetic suction can be controlled to realize high-speed and high-precision position control of the work.

In order to solve the above problems, the control method according to one aspect of the present invention is a control method of a control device that outputs a command value calculated from a target trajectory to the servo control system, and the response delay of the servo control system. The servo control is performed from the detection result of the detection device at the detection time when the target position calculated from the target trajectory in consideration of time coincides with the detection position which is the position where the detection device detects the detection target. The first deviation amount calculation step for calculating the first deviation amount, which is the deviation amount from the detection position of the position of the work whose position is controlled by the system, and the feedback position of the servo control system at the detection time. The second deviation amount calculation step for calculating the second deviation amount, which is the deviation amount from the target position calculated in consideration of the response delay time at the detection time, and the target position calculated from the target trajectory. It includes a command value generation step of generating the command value from the corrected target position corrected by the first deviation amount and the second deviation amount and the response delay time.

According to the above configuration, the control method is based on the corrected target position obtained by correcting the target position by the first deviation amount and the second deviation amount, and the response delay time of the servo control system. The command value to be output to the servo control system is generated.

Here, when the feedback position and the "target position considering the response delay time of the servo control system" completely match at the detection time, the feedback position is set to the detection position at the detection time. It will be an exact match. Therefore, when the feedback position and the "target position considering the response delay time of the servo control system" completely match at the detection time, the amount of deviation of the work position from the feedback position is determined. It can be specified only from the first deviation amount.

However, in reality, at the detection time, the feedback position and the "target position in consideration of the response delay time of the servo control system" may not completely match.

Therefore, the control method increases the "deviation amount of the position of the work from the feedback position" at the detection time by considering the second deviation amount in addition to the first deviation amount. Specify for accuracy. Then, the control method includes the corrected target position obtained by correcting the "target position calculated from the target trajectory" by the specified "deviation amount of the work position from the feedback position", and the servo control system. The command value is generated from the response delay time of.

Therefore, the control method can control the position of the work with high accuracy by considering the deviation between the position of the servo control system (feedback position) and the position of the work whose position is controlled by the servo control system. It has the effect of being able to be transformed.

Further, the control method calculates the first deviation amount from the detection result at the detection time when "the target position calculated in consideration of the response delay time matches the detection position". Therefore, in the control method, it is not necessary to stop the movement of the work by the servo control system in order to calculate the first deviation amount.

Therefore, the control method has the effect that high-precision position control for the work can be executed at high speed, in other words, high-speed and high-precision position control for the work can be realized.

According to one aspect of the present invention, high accuracy of position control of the work is realized by considering the deviation between the position of the servo control system itself and the position of the work whose position is controlled by the servo control system. It has the effect of being able to.

It is a figure which shows the main part structure of the control device which concerns on Embodiment 1 of this invention. It is a figure which shows the whole outline of the control system including the control device of FIG. It is a figure explaining the application example of the control system of FIG. It is a figure explaining the variation of the imaging method of a work. It is a figure explaining the problem which may occur when the captured image is generated without stopping the movement of a work. It is a figure explaining the example of the captured image which solved the problem described in FIG. 5 by adjusting the imaging time. It is a figure explaining the method of coping with "the deviation of shooting timing". It is a figure which shows an example of the operation profile when the detection position is "100". It is a figure explaining that it is necessary to consider the amount of "shift of shooting timing" in order to specify the amount of misalignment. It is a figure explaining the influence of "the shift of a shooting timing" on the position shift in one dimension. It is a figure explaining the situation which shortens the moving distance of a work. It is a figure which shows an example of the operation profile when the detection position is "40". It is a figure explaining the difference of the influence of "the shift of a shooting timing" by the difference of a pixel resolution. It is a figure explaining the deviation between "the feedback position of a servo control system" and "the target position of a servo control system in consideration of the response delay time of a servo control system" at the detection time. It is a flow diagram explaining the whole outline of the process executed by the control device of FIG. It is a flow diagram explaining an example of the detection instruction time determination process of FIG. It is a flow chart explaining an example of each of the 1st deviation amount calculation process and the 2nd deviation amount calculation process of FIG.

[Embodiment 1]
Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated. In the present embodiment, the control device 10 that controls the servo control system 20 (particularly, the position of the hand 23) by outputting the command value Cm to the servo control system 20 is "command value calculated from the target trajectory Tt". A typical example of a "control device that outputs Cm to the servo control system" will be described.

In the control device 10 described in detail below, the position Pw of the work 40 and the feedback position Pf (specifically, the position of the hand 23) of the servo control system 20 for moving the work 40 do not match. Also, the work 40 can be moved to a desired position.

Generally, even if the actual position (feedback position) of the servo control system for each time and the target position for each time of the servo control system can be matched, the work to be moved by the servo control system is desired. It is not always possible to move to the position of. When the position of the work and the actual position of the servo control system that moves the work deviate from each other, the position of the work moved by the servo control system deviates from the actual position of the servo control system by the amount of the deviation between the two. This is to become.

Therefore, the control device 10 specifies the amount of deviation between the position Pw of the work 40 and the actual position (feedback position Pf) of the servo control system 20 that moves the work 40, and the servo control system 20 takes this deviation amount into consideration. By controlling the work 40, the work 40 is moved to a desired position.

Therefore, the control device 10 is suitable for a case where the position Pw of the work 40 moved by the servo control system 20 and the actual position (feedback position Pf) of the servo control system 20 deviate each time the work 40 is to be moved. be. For example, in the case where the control device 10 grips the work 40 by the hand 23 (picking operation) and moves the hand 23 holding the work 40 to place the work 40 in a desired position (place operation). Suitable.

In the above cases, each time the work 40 is gripped by the hand 23, the "position Pw of the work 40 (eg, the center position of the work 40)" and the "position of the hand 23 (that is, the feedback position of the servo control system 20)" There is a possibility that a deviation may occur between "Pf)". The magnitude of the deviation (that is, the amount of deviation) between the "position Pw of the work 40" and the "position of the hand 23" may be different each time the work 40 is gripped, that is, each time the picking operation is performed. However, there is a possibility that the magnitude (that is, the amount of deviation) of "the deviation between the" position Pw of the work 40 "and the" position of the hand 23 "when the work 40 is gripped" changes during the movement of the work 40. , Considered low.

Therefore, the control device 10 calculates the magnitude (that is, the amount of deviation) of the deviation between the "position Pw of the work 40" and the "position of the hand 23" each time the work 40 is gripped by the hand 23. Then, the control device 10 can move the work 40 to a desired position by controlling the servo control system 20 in consideration of the calculated deviation amount.

In the following description, "the position of the hand 23 (that is, the feedback position Pf of the servo control system 20)" and "the position Pw of the work 40 that moves with the movement of the hand 23 (eg, the center position of the work 40)". ) ”Is also referred to as“ misalignment ”. In particular, the deviation between the "position of the hand 23" and the "position Pw of the work 40 gripped by the hand 23" is also referred to as "grasping deviation", that is, the "grasping deviation" is that the work 40 grips the hand 23. Refers to the "misalignment" when it is done.

For example, the control device 10 specifies the magnitude (grip deviation amount) of the grip deviation generated during the picking operation each time the picking operation is performed, and controls the servo control system 20 in consideration of the specified grip deviation amount. Places the work 40 in a desired position with high accuracy. Further, the control device 10 specifies the size of the gripping deviation generated during the picking operation during the movement of the hand 23, thereby stopping the movement of the hand 23 that has completed the picking operation and the size of the gripping deviation. The position control of the work 40 is speeded up as compared with the case of specifying.

Hereinafter, in order to move the work 40 to a desired position, "the deviation between the position Pw of the work 40 moved by the servo control system 20 and the actual position (feedback position Pf) of the servo control system 20" is specified. The details of the control device 10 will be described. That is, in the following, the control device 10 increases the position control of the work 40 by considering the "deviation between the position Pw of the work 40 and the feedback position Pf of the servo control system 20", that is, the "positional deviation". The explanation will focus on the points to improve the accuracy. In particular, the control device 10 identifies the "grip deviation" which is the "position deviation" when the work 40 is gripped by the hand 23, and considers the specified "grip deviation" to position the work 40 at a desired position. An example of placing the device with high accuracy will be described.

The control device 10 is a servo control system considering "positional deviation", that is, "displacement between the position Pw of the work 40 moved by the servo control system 20 and the actual position (feedback position Pf) of the servo control system 20". In addition to the 20 controls, the following controls may be performed. That is, the control device 10 may further perform control to match the feedback position Pf of the servo control system 20 for each time with the target position Pt of the servo control system 20 for each time. However, since the description of the control for matching the feedback position Pf of the servo control system 20 for each time with the target position Pt of the servo control system 20 for each time is not the object of the present embodiment, the details will be omitted.

§1. Application example (Overview of control system)
In order to facilitate understanding of the control device 10 according to one aspect of the present invention, first, an example of a situation to which the present invention is applied, specifically, an outline of a control system 1 including the control device 10 is shown in the figure. 2 will be described.

FIG. 2 is a diagram showing an overall outline of the control system 1. The control system 1 is a master-slave control system including a control device 10 as a master and a servo control system 20 and a detection system 30 as one or more slaves connected to the master via a network. The control device 10 is called a "master" in the sense that it manages data transmission via a network in the control system 1, while the "slave" is managed by the master and is installed in a factory, for example. Collects and controls data on the equipment. In the control system 1, for example, EtherCAT (registered trademark) can be used as a network connecting the control device 10 as a master and the servo control system 20 and the detection system 30 as slaves.

The "master" and "slave" are defined by focusing on the control function of data transmission on the network, and what kind of information is transmitted and received between the devices is not particularly limited.

(Control device)
As a master, the control device 10 acquires (receives) data indicating control results (eg, control amount and detection result) output by slaves such as the servo control system 20 and the detection system 30 for each control cycle Cc. Further, the control device 10 outputs control signals Cs (control instructions) including a command value Cm and a detection instruction time aTd to slaves such as the servo control system 20 and the detection system 30 as a master for each control cycle Cc. (Send).

The control device 10 is an industrial control device such as a PLC (Programmable Logic Controller) that executes a user program for controlling a control device such as a servomotor 22. In the control system 1, the control device 10 is an upper controller for the servo driver 21 as a lower controller.

Specifically, the control device 10 outputs the command value Cm generated from the target trajectory Tt for each control cycle Cc to the servo control system 20 including the servo driver 21 for each control cycle Cc. In the servo control system 20, the servo driver 21 that has received the command value Cm performs feedback control so that the control amount, which is the output of the servomotor 22 or the like to be controlled, follows the command value Cm. Then, the control device 10 acquires data related to the output (control amount, for example, torque, speed, position, etc.) of the servomotor 22 from the servo control system 20 (particularly, the servo driver 21) for each control cycle Cc. .. The control device 10 further generates a command value Cm in the servo control system 20 based on the control amount received from the servo control system 20 (eg, the feedback position Pf for each control cycle Cc), and the generated command value Cm is servo-controlled. The servo control system 20 is controlled by transmitting to the system 20.

Here, the control device 10 controls, for example, a plurality of servo control systems 20, and specifically, controls a plurality of servo control systems 20 as follows. That is, the control device 10 generates a command trajectory Co for each servo control system 20 from the target trajectory Tt for each of the plurality of servo control systems 20. Then, the control device 10 outputs the "command value Cm for each servo control system 20" generated from the command trajectory Co for each servo control system 20 for each control cycle Cc for each of the plurality of servo control systems 20. Coordinated control of a plurality of servo control systems 20. The control device 10 operates the plurality of servo control systems 20 by generating "command value Cm for each servo control system 20" in consideration of the response delay time Ds of each of the plurality of servo control systems 20. Synchronize at the level of control).

In the example shown in FIG. 2, the control device 10 has command trajectories Co (A) and Co of the servo control systems 20 (A), 20 (B), 20 (C), and 20 (D) from the target orbit Tt, respectively. (B), Co (C), Co (D) are generated. The control device 10 has servo control systems 20 (A), 20 (B), 20 (C), 20 (from each of the command trajectories Co (A), Co (B), Co (C), and Co (D). The respective command values Cm (A), Cm (B), Cm (C), and Cm (D) of D) are generated. In particular, the control device 10 has response delay times Ds (A), Ds (B), Ds (C), respectively, of the servo control systems 20 (A), 20 (B), 20 (C), and 20 (D). The command values Cm (A), Cm (B), Cm (C), and Cm (D) are generated in consideration of Ds (D). The control device 10 outputs the command values Cm (A), Cm (B), Cm (C), and Cm (D) for each control cycle Cc of the servo control system 20 to obtain the servo control system 20 (A). , 20 (B), 20 (C), 20 (D) are coordinated and controlled.

Further, in the control system 1, the control device 10 outputs the control signal Cs for which the detection instruction time aTd is specified, for example, for each control cycle Cc. Further, the control device 10 acquires the detection result (eg, the captured image Im) which is the result of the detection operation (eg, the imaging operation) executed by the detection system 30 from the detection system 30, for example, for each control cycle Cc. (Receive).

Although the details will be described later, the control device 10 designates the detection instruction time aTd, which is the time obtained by correcting the detection time Td by the “response delay time Dd of the detection system 30”, in the control signal Cs. Then, the control device 10 outputs the control signal Cs for which the detection instruction time aTd is specified to the detection system 30, so that the image pickup device 33 (detection device) executes the detection operation (imaging operation) at the detection time Td. Let me.

In the example shown in FIG. 2, four servo control systems 20 (A), 20 (B), 20 (C), and 20 (D) and one servo control system 20 are used for the control device 10 as a master. An example in which the detection system 30 is connected as a slave is shown. However, it is not essential that the number of servo control systems 20 connected to the control device 10 is four, and if the control system 1 has one or more servo control systems 20 connected to the control device 10 as a master. Often, for example, there may be five.

In the following description, when it is necessary to distinguish each of the plurality of servo control systems 20 in the servo control system 20, the reference numerals are "(A)", "(B)", "(C)", and the like. ..., Add a subscript such as "(Z)" to distinguish. For example, it is described as "servo control system 20 (A)", "servo control system 20 (B)", "servo control system 20 (C)", ..., "Servo control system 20 (Z)" to distinguish them. do. When it is not necessary to distinguish each of the plurality of servo control systems 20, it is simply referred to as "servo control system 20".

(Servo control system)
The servo control system 20 is a feedback control system that controls the output (for example, position) of the servo control system 20 according to the command value Cm from the control device 10, and specifically controls the position of the hand 23. The servo control system 20 controls the position Pw of the work 40 held by the hand 23, for example, by controlling the position of the hand 23. The servo control system 20 includes a servomotor 22 as an actuator (Actuator) that changes the position Pw of the hand 23, and a servo driver 21 that controls the servomotor 22.

The servo driver 21 is a control device for the servo motor 22, receives control signals Cs (specifically, command value Cm) from the control device 10 for each control cycle Cc, and receives the received control signals Cs according to the servo motor 22. Control the drive of. Further, the servo driver 21 acquires actual measurement values related to the output of the servo motor 22 such as position, speed, and torque from a position sensor and a torque sensor connected to the shaft of the servo motor 22, and data related to these measured values. Is output to the control device 10 for each control cycle Cc.

The servo motor 22 is an actuator whose output (specifically, the position of the hand 23) is controlled according to the control of the servo driver 21, and is, for example, a linear actuator. The servomotor 22 changes the position of the hand 23, for example, by driving the shaft of the manipulator including the hand 23. The servomotor 22 changes the position Pw of the work 40 by changing the position of the hand 23, and changes the position Pw of the work 40 gripped by the hand 23, for example, by changing the position of the hand 23.

The hand 23 is a gripping portion that grips the work 40, and grips (picks) the work 40 by, for example, vacuum suction or magnetic suction. For example, in order to realize vacuum suction, a vacuum pump may be provided on the hand 23 to control the operation of the vacuum pump. In the following description, the "output position of the servo control system 20" as an actually measured value related to the output of the servo motor 22, that is, the position of the hand 23 may be referred to as a "feedback position Pf".

For example, the output of each of the servomotors 22 (A), 22 (B), and 22 (C) determines the position of the hand 23 on each of the X-axis, Y-axis, and Z-axis orthogonal to each other. Further, the output of the servomotor 22 (D) determines the amount of rotation of the hand 23 about the Z axis. Each of the servo drivers 21 (A), 21 (B), 21 (C), and 21 (D) is the output of each of the servo motors 22 (A), 22 (B), 22 (C), and 22 (D). Is controlled, that is, each drive is controlled.

Further, the servo driver 21 (A) transmits the feedback position Pf (A) on the X axis of the hand 23 to the control device 10 as one of the actually measured values (control amount) related to the output of the servo motor 22 (A). .. Similarly, the servo driver 21 (B) transmits the feedback position Pf (B) on the Y axis of the hand 23 to the control device 10 as one of the control amounts of the servo motor 22 (B). The servo driver 21 (C) transmits the feedback position Pf (C) on the Z axis of the hand 23 to the control device 10 as one of the control amounts of the servo motor 22 (C). The servo driver 21 (D) uses the rotation amount of the hand 23 around the Z axis as one of the control amounts of the servomotor 22 (D) as the feedback position Pf (D) in the control device 10. Send.

(Detection system)
The detection system 30 generates a detection result that is the result of detecting the work 40, and in particular, generates and generates information for calculating "the amount of deviation between the position Pw of the work 40 and the detection position Pd" as the detection result. Notify (transmit) the detected detection result to the control device 10. The detection system 30 illustrated in FIG. 2 is a communication that executes communication with an image pickup device 33, which is a detection device, an image pickup control device 32 that controls a detection operation (eg, an image pickup operation) by the image pickup device 33, and an image pickup control device 32. The device 31 and the like are included.

Upon receiving the detection trigger (imaging trigger) from the imaging control device 32, the imaging device 33 executes a detection operation (imaging operation), and the result of the executed detection operation is, for example, an imaging generated by executing the imaging operation. The image Im is output (transmitted) to the image pickup control device 32.

The image pickup control device 32 outputs (transmits) a detection trigger (imaging trigger) to the image pickup device 33 to cause the image pickup device 33 to execute a detection operation (imaging operation), and the image pickup device 33 detects the image. The detection result (eg, captured image Im) which is the execution result of the operation is received. In particular, when the image pickup control device 32 receives an output instruction (detection instruction) instructing the output of the detection trigger (imaging trigger) to the image pickup device 33 from the communication device 31, the image pickup control device 32 transmits the detection trigger to the image pickup device 33.

When the image pickup control device 32 receives the detection result (eg, the captured image Im) which is the execution result of the detection operation from the image pickup device 33, the image pickup control device 32 outputs the received detection result to the control device 10 via the network (eg). Send). For example, the image pickup control device 32 controls the detection result (eg, the image pickup image Im), which is the execution result of the detection operation by the image pickup device 33, via the network in a certain control cycle Cc after the detection time Td. Output (send) to.

Although the details will be described later, when the image pickup control device 32 receives the detection result (eg, the captured image Im) which is the execution result of the detection operation from the image pickup device 33, the image pickup control device 32 analyzes the received detection result and outputs the analysis result to the network. May be output to the control device 10 via. For example, the image pickup control device 32 executes image analysis on the captured image Im generated by the image pickup device 33, and controls the result of the image analysis via a network in a certain control cycle Cc after the detection time Td. It may be output to the device 10.

Specifically, the image pickup control device 32 is the amount of deviation between the position Pw of the work 40 (eg, the center position of the work 40) and the reference point Rb in the image captured image Im by image analysis with respect to the image captured image Im. The amount of "misalignment at" may be calculated. Then, the image pickup control device 32 may output the calculated "positional deviation in the image" amount to the control device 10 via the network, for example, the calculated "positional deviation in the image" amount. May be transmitted to the control device 10 in a certain control cycle Cc after the detection time Td.

The communication device 31 receives the control signal Cs from the control device 10 for each control cycle Cc, and sends an output instruction (detection instruction) to the image pickup control device 32 at the detection instruction time aTd specified in the received control signal Cs. Is output (sent).

In the detection system 30, a predetermined time is required from the communication device 31 transmitting the output instruction to the image pickup control device 32 until the image pickup device 33 executes the detection operation, and this predetermined time is referred to as “detection system 30”. Response delay time Dd ". The “response delay time Dd of the detection system 30” is also referred to as the “response delay time of the image pickup device 33 (detection device)”.

(Application example of control system)
FIG. 3 is a diagram for explaining an application example of the control system 1, and specifically, is a diagram for explaining an example in which the control system 1 is applied to a robot application that performs a picking operation (suction operation) and a place operation. .. That is, as illustrated in FIG. 3, the control system 1 (particularly, the control device 10) “takes out the work 40 from the parts pallet (picking operation) and mounts the taken-out work 40 at a predetermined position (place operation). ) ”Applies to the pick and place process.

In the example shown in FIG. 3, the work 40 is a fine electronic component of 1 mm or less, and is, for example, a laminated ceramic capacitor, a crystal oscillator, an IC chip, and various other elements. In the work of mounting such electronic components on a substrate, miniaturization of components and circuits is progressing, and higher accuracy of picking operation and place operation is required, and the number of parts used is increasing. Therefore, it is also essential to speed up the picking operation and the place operation.

Therefore, the control system 1 (particularly, the control device 10) considers the positional deviation (that is, the displacement between the position Pw of the work 40 (eg, the center position of the work 40) and the position of the hand 23), so that the work 40 To the desired position with high precision.

That is, in order to accurately place (place) the work 40 gripped by the hand 23 by the picking operation at a desired position, the control system 1 (particularly, the control device 10) considers the misalignment (grasping misalignment). Then, the position of the hand 23 is controlled. For example, when the hand 23 grips the work 40 at a position on the right side of the center position of the work 40, the control device 10 that intends to place the work 40 in a desired position sets the position of the hand 23 at the initial position. Move (correct) to the right of the target position. Similarly, when the hand 23 grips the work 40 at a position on the left side of the center position of the work 40, the control device 10 that intends to place the work 40 in a desired position initially sets the position of the hand 23. Shift (correct) to the left of the target position of.

Further, although the details will be described later, the control system 1 (particularly, the control device 10) captures the moving work 40 without stopping the movement of the work 40, and the position is obtained from the captured image Im obtained as a result. Accurately grasp the deviation (grasping deviation). Therefore, the control system 1 (particularly, the control device 10) can realize high-precision position control of the work 40 in consideration of the position shift (grasping shift) at high speed.

As illustrated in FIG. 3, in the control system 1, the position of the hand 23, that is, the output (position) of the servo control system 20 is controlled by the control device 10. That is, the control device 10 causes the servo driver 21 to control the output (output position) of the servo motor 22 by transmitting the command value Cm to the servo driver 21.

For example, the positions of the hand 23 on each of the X-axis, Y-axis, and Z-axis orthogonal to each other are the servo control systems 20 (A), 20 (B), and 20 (C), respectively. Output (output position) of. Further, the rotation amount of the hand 23 around the Z axis is the output (output rotation amount) of the servo control system 20 (D).

Specifically, the servo driver 21 (A) that receives the command value Cm (A) from the control device 10 controls the servo motor 22 (A), and the hand 23 is moved in the X-axis direction by the servo motor 22 (A). Moving. Further, the control result (output) of the servomotor 22 (A) is fed back to the servo driver 21 (A).

Similarly, each of the servo drivers 21 (B) and 21 (C) that received the command values Cm (B) and (C) from the control device 10 is the servomotors 22 (B) and 22 (C), respectively. To control. Each of the servomotors 22 (B) and 22 (C) causes the hand 23 to move in each of the Y-axis direction and the Z-axis direction. Further, the control results of the servomotors 22 (B) and 22 (C) are fed back to each of the servo drivers 21 (B) and 22 (C).

Further, the servo driver 21 (D) that receives the command value Cm (D) from the control device 10 controls the servo motor 22 (D), and the hand 23 is rotated about the Z axis by the servo motor 22 (D). .. Further, the control result of the servomotor 22 (D) is fed back to the servo driver 21 (D).

The work 40 gripped by the hand 23 by the picking operation moves with the movement of the hand 23. According to the instruction from the control device 10 (specifically, the detection instruction time aTd), the image pickup device 33 takes an image of the work 40 gripped by the hand 23 by the picking operation, and generates the captured image Im. The captured image Im generated by the image pickup device 33 is transmitted to the control device 10.

The control device 10 identifies the positional deviation (that is, the displacement between the position Pw of the work 40 (eg, the center position of the work 40) and the position of the hand 23) by image analysis with respect to the captured image Im. Then, the control device 10 mounts the work 40 at a desired position at high speed and with high accuracy by controlling the position (eg, place position) of the hand 23 in consideration of the specified positional deviation.

However, it is not essential that the control device 10 performs image analysis on the captured image Im. The control device 10 determines the position Pw of the work 40 from the amount of "positional deviation in the image" which is the amount of deviation between the position Pw of the work 40 (eg, the center position of the work 40) and the reference point Rb in the captured image Im. It suffices if the first deviation amount Fd, which is the deviation amount from the detection position Pd, can be specified. It may be the image pickup control device 32 that performs the image analysis on the captured image Im, in other words, the image pickup control device 32 calculates the amount of "positional deviation in the image" by the image analysis on the captured image Im. You may. In that case, the control device 10 acquires the amount of "positional deviation in the image" from the image pickup control device 32, and specifies (calculates) the first deviation amount Fd from the acquired "positional deviation in the image" amount. ).

(First device related to the method of imaging the work: generation of captured images without stopping)
FIG. 4 is a diagram illustrating variations of the imaging method of the work 40. (A) of FIG. 4 is conventionally used to generate an imaged image Im for specifying a positional deviation (that is, a displacement between the position Pw of the work 40 (eg, the center position of the work 40) and the position of the hand 23). It is a figure explaining the method of.

That is, conventionally, a method has been generally used in which the movement of the hand 23 holding the work 40 is stopped, the work 40 held by the hand 23 is imaged, and the captured image Im is generated. Specifically, in the conventional control system, the moving speed (servo speed Vs) of the hand 23 holding the work 40 is once set to "0", and after the vibration of the hand 23 or the like has subsided, that is, the vibration damping waiting time is set. After that, a detection trigger was output to cause the image pickup device to perform imaging.

"The movement of the hand 23 holding the work 40 is stopped to generate the captured image Im." The conventional method can generate the captured image Im capable of detecting the positional deviation (grasping deviation) of the work 40 with high accuracy. Has the advantage of.

However, since the conventional control system executes imaging after the processes of "stopping the movement of the hand 23" and "waiting until the vibration damping waiting time elapses", it is shown in FIG. 4A. As described above, there is a problem that the time required for performing imaging becomes long.

FIG. 4B shows a “grip deviation (that is, a deviation between the position Pw of the work 40 (eg, the center position of the work 40)” and the position of the hand 23, which is executed by the control system 1 (particularly, the control device 10). ) Is generated to identify the captured image Im ”. The control device 10 generates the captured image Im without stopping the movement of the hand 23, that is, without stopping. Specifically, as shown in FIG. 4B, the control device 10 is moving the hand 23 without setting the moving speed (servo speed Vs) of the hand 23 holding the work 40 to “0”. The detection trigger is output to cause the image pickup apparatus 33 to perform imaging.

The method of "generating the captured image Im without stop" of the control device 10 shown in FIG. 4 (B) is the method of "stopping the movement of the hand 23" of the conventional control system shown in FIG. 4 (A). The tact can be increased as compared with the method of "generating the captured image Im from".

(Problems that can occur when a captured image is generated without stopping)
FIG. 5 is a diagram illustrating a problem that may occur when a captured image Im is generated without stopping (that is, without stopping the movement of the work 40). In each of FIG. 5A and FIG. 5B, the intersecting point of the alternate long and short dash line is "a reference point Rb corresponding to the detection position Pd in the captured image Im (eg, the center point of the captured image Im). ) ”Is shown. Further, the center position of the circle indicated by the dotted line indicates "the position of the hand 23 at the detection time Td", that is, "the feedback position Pf (actual position) of the servo control system 20 at the detection time Td". Further, the star mark indicates the "position Pw of the work 40 (eg, the center position of the work 40)", and the dotted arrow indicates "the deviation between the position Pw of the work 40 and the" position of the hand 23 at the detection time Td "" (quantity). ) Is shown.

In each of FIG. 5A and FIG. 5B, the image pickup apparatus 33 executes imaging at the timing when the position Pw of the work 40 (eg, the center position of the work 40) and the detection position Pd coincide with each other. is doing. That is, the captured image Im is generated at the timing when the position Pw of the work 40 and the detection position Pd match. Therefore, in each of the captured images Im of FIGS. 5A and 5B, the star mark (that is, the position Pw of the work 40) and the reference point R corresponding to the detection position Pd coincide with each other. ing.

In the example shown in FIG. 5A, the position Pw of the work 40 and the position of the hand 23 coincide with each other at the timing when the captured image Im is generated. Therefore, in the captured image Im, the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line (that is, the position of the hand 23) coincide with each other.

In the example shown in FIG. 5B, the position Pw of the work 40 and the position of the hand 23 do not match at the timing when the captured image Im is generated, that is, the position Pw of the work 40 and the hand. It is out of the position of 23. Therefore, in the captured image Im, the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line (that is, the position of the hand 23) do not match, that is, are deviated.

Here, as shown in each of FIG. 5A and FIG. 5B, there is a work 40 between the hand 23 and the image pickup device 33, that is, the hand 23 is the work 40. The hand 23 is not actually imaged because it is hidden by. That is, in each of the captured images Im of FIGS. 5 (A) and 5 (B), the circle shown by the dotted line is not actually shown, and from the captured image Im, "the hand 23 at the detection time Td". Position (feedback position Pf) ”is unknown.

Therefore, it is not possible to actually distinguish between the captured image Im of FIG. 5 (A) and the captured image Im of FIG. 5 (B). That is, at the timing when the captured image Im is generated, it is captured whether the position Pw of the work 40 and the position of the hand 23 coincide with each other, or whether the position Pw of the work 40 and the position of the hand 23 deviate from each other. It cannot be determined only by image analysis for image Im.

Since the hand 23 is not actually imaged, the position of the hand 23 cannot be grasped only by image analysis with respect to the captured image Im. Therefore, it is not possible to grasp the "misalignment between the position Pw of the work 40 and the position of the hand 23", that is, the misalignment (grasping misalignment) only by image analysis with respect to the captured image Im. Only the image analysis of the captured image Im can be grasped by the position Pw of the work 40 actually captured by the captured image Im and the reference point R of the captured image Im (eg, the center point of the captured image Im). It is only the amount of deviation from. Since the hand 23 is not actually captured by the captured image Im, it is not possible to grasp the amount of deviation between the position of the hand 23 and the reference point R of the captured image Im only by image analysis with respect to the captured image Im.

That is, when the image is taken at the timing when the position of the hand 23 and the detection position Pd do not match, even if the image analysis is performed on the captured image Im generated by the imaging, the amount of misalignment (positional deviation amount only from the image analysis result) ( Gripping deviation amount) cannot be calculated. In other words, in order to calculate the amount of "deviation between the position Pw of the work 40 and the position of the hand 23" by image analysis for the captured image Im, the image pickup device is at the time when the position of the hand 23 and the detection position Pd match. It is necessary to have 33 perform imaging.

In the following description, "the timing at which the imaging device 33 performs imaging does not match (shift) at the time when the position of the hand 23 and the detection position Pd coincide" is also referred to as "shift in shooting timing". .. It can also be said that the "difference in shooting timing" means that "the position of the hand 23 and the detection position Pd do not match (shift) at the timing when the imaging device 33 executes imaging". When the "shooting timing shift" occurs, the position of the hand 23 and the detection position Pd do not match when the imaging is executed, that is, the position of the hand 23 and the reference point R in the captured image Im (eg,). , The center point of the captured image Im) does not match. Therefore, it is not possible to grasp the amount of misalignment (grasping misalignment), that is, the amount of "misalignment between the position Pw of the work 40 and the position of the hand 23" only by image analysis with respect to the captured image Im.

The control device 10 executes the method of "generating the captured image Im without stopping the movement of the hand 23" shown in FIG. 4 (B), and thereby "moving the hand 23" shown in FIG. 4 (A). The tact can be increased as compared with the conventional method of "generating the captured image Im after stopping the operation". However, in the case of "generating the captured image Im without stopping the movement of the hand 23", as described with reference to FIG. 5, when the "shooting timing shift" occurs, the image analysis of the captured image Im alone is sufficient. There arises a problem that the amount of misalignment (the amount of gripping misalignment) cannot be calculated.

(Second device related to the method of imaging the work)
FIG. 6 is a diagram illustrating an example of a captured image Im that solves the problem described in FIG. 5 by adjusting the detection time Td. In each of FIG. 6A and FIG. 6B, the intersecting point of the alternate long and short dash line is "a reference point Rb corresponding to the detection position Pd in the captured image Im (eg, the center point of the captured image Im). ) ”Is shown. Further, the center position of the circle indicated by the dotted line indicates "the position of the hand 23 at the detection time Td", that is, "the feedback position Pf of the servo control system 20 at the detection time Td". Further, the star mark indicates "the position Pw of the work 40 (eg, the center position of the work 40)", and the solid arrow indicates "the deviation between the position Pw of the work 40 and the reference point Rb in the captured image Im" (amount). , Shown.

In order to solve the problem described with reference to FIG. 5, the control device 10 takes an image on the image pickup device 33 at a time when the position of the hand 23 (that is, the feedback position Pf of the servo control system 20) and the detection position Pd coincide with each other. Try to get it done.

However, even if the image pickup device 33 is instructed to take an image when the coincidence between the feedback position Pf of the servo control system 20 and the detection position Pd is confirmed, the image pickup device 33 still has the feedback position Pf and the detection position Pd of the servo control system 20. It is not possible to take an image at the same time as. As described above, the communication between the detection system 30 including the image pickup device 33 and the control device 10 is executed for each control cycle Cc, and the response delay time Dd of the detection system 30 (eg, the response of the image pickup device 33). This is because the delay time Dd) also exists.

Therefore, the control device 10 calculates the time predicted that "the feedback position Pf of the servo control system 20 and the detection position Pd match" as the "detection time Td". Then, the control device 10 outputs the detection instruction time aTd to the detection system 30 in advance so that the image pickup device 33 can execute the image pickup at the detection time Td.

That is, in the control device 10 (particularly, the detection time determination unit 1160 in FIG. 1), first, "the target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20 coincides with the detection position Pd. Let "time" be the detection time Td. For example, the detection time determination unit 1160 sets the time at which the response delay time Ds of the servo control system 20 has elapsed from the “time when the target position Pt of the servo control system 20 and the detection position Pd match” as the detection time Td. .. Then, the detection time determination unit 1160 sets the "time in which the detection time Td is corrected by the response delay time Dd of the detection system 30" as the detection instruction time aTd. For example, the detection time determination unit 1160 sets “the time retroactive from the detection time Td to the response delay time Dd of the detection system 30” as the detection instruction time aTd. Then, the control device 10 (particularly, the command unit 1210 in FIG. 1) outputs the detection instruction time aTd to the detection system 30 in advance.

The control device 10 outputs the detection instruction time aTd, which is the “time in which the detection time Td is corrected by the response delay time Dd of the detection system 30”, to the detection system 30 in advance, whereby the detection time is transmitted to the image pickup device 33. Imaging can be performed at Td. Then, at the detection time Td, the "target position Pt of the servo control system 20 considering the response delay time Ds of the servo control system 20" and the detection position Pd coincide with each other. Therefore, if the "target position Pt of the servo control system 20 considering the response delay time Ds of the servo control system 20" and the "feedback position Pf of the servo control system 20" match, the following relationship is established. That is, at the detection time Td, the "feedback position Pf of the servo control system 20" and the detection position Pd coincide with each other.

In each of the captured images Im of FIGS. 6A and 6B, the control device 10 outputs the detection instruction time aTd to the detection system 30 in advance, so that the feedback position of the servo control system 20 is obtained. It is a captured image Im captured at a time when Pf and the detection position Pd coincide with each other. That is, in each of FIG. 6A and FIG. 6B, the image pickup apparatus 33 coincides with the feedback position Pf (that is, the position of the hand 23) of the servo control system 20 and the detection position Pd. , Performing imaging.

Therefore, in each of the captured images Im of FIGS. 6A and 6B, the reference point R (that is, the intersection of the center position of the circle indicated by the dotted line (that is, the position of the hand 23) and the two-dot chain line intersects (that is, that is). , Detection position Pd).

In the example shown in FIG. 6A, the position Pw of the work 40 and the position of the hand 23 coincide with each other at the timing when the captured image Im is generated, as in the case of FIG. 5A. Therefore, in the captured image Im, the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line (that is, the position of the hand 23) coincide with each other.

Further, in the example shown in FIG. 6B, the position Pw of the work 40 and the position of the hand 23 coincide with each other at the timing when the captured image Im is generated, as in the case of FIG. 5B. That is, the position Pw of the work 40 and the position of the hand 23 are out of alignment. Therefore, in the captured image Im, the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line (that is, the position of the hand 23) do not match, that is, are deviated.

Here, as in FIG. 5, in FIG. 6, since the hand 23 is not actually hidden by the work 40 and imaged, the position of the hand 23 is grasped only by image analysis with respect to the captured image Im. It is not possible.

However, as described above, the "center position of the circle indicated by the dotted line (that is, the position of the hand 23)" that is not actually reflected in each of the captured images Im of FIGS. 6A and 6B. Can be estimated to coincide with the reference point R (that is, the detection position Pd). Therefore, the control device 10 determines that "the amount of deviation between the" center position of the circle indicated by the dotted line (that is, the position of the hand 23) "and the star mark (that is, the position Pw of the work 40) that is not actually reflected". , Can be estimated to be equal to "the amount of deviation between the reference point R and the star mark". In other words, the control device 10 determines the position Pw of the work 40 and the position of the hand 23 (feedback position Pf) from the solid line arrow indicating "the deviation between the position Pw of the work 40 and the reference point Rb in the captured image Im". The amount of deviation (the amount of displacement) can be calculated.

(Method of specifying the amount of misalignment (grasping misalignment) when there is no "misalignment of shooting timing")
The contents explained so far can be summarized as follows. That is, the control device 10 (particularly, the detection time determination unit 1160 in FIG. 1) first sets the detection time Td to "the target position Pt of the servo control system 20 calculated from the target trajectory Tt matches the detection position Pd. It is specified from the time and the response delay time Ds of the servo control system 20.

Then, the control device 10 (detection time determination unit 1160) calculates the detection instruction time aTd, which is the time obtained by correcting the detection time Td by the “response delay time Dd of the detection system 30”. By transmitting the detection instruction time aTd to the detection system 30 (particularly, the communication device 31) in advance, the control device 10 causes the image pickup device 33 to perform imaging at the detection time Td.

By executing the imaging at the detection time Td, the image pickup apparatus 33 has the captured image in which the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" and the detection position Pd match. Generate Im. That is, in the captured image Im, the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" and the reference point Rb (eg, the center point of the captured image Im) coincide with each other. ing. Therefore, when the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" and the feedback position Pf of the servo control system 20 (that is, the position of the hand 23) match, the captured image At Im, the position of the hand 23 and the reference point Rb coincide with each other.

The control device 10 (particularly, the first deviation amount calculation unit 1170 in FIG. 1) determines the position Pw (eg, the center position of the work 40) and the reference point Rb of the work 40 in the captured image Im by image analysis with respect to the captured image Im. The amount of "positional deviation in the image", which is the amount of deviation, is calculated. The amount of "positional deviation in the image" in the captured image Im corresponds to "the amount of deviation between the position Pw of the work 40 and the detection position Pd at the detection time Td (the first deviation amount Fd described later)".

Then, the first deviation amount calculation unit 1170 determines the position Pw of the work 40 (eg, the center position of the work 40) and the hand 23 from the “first deviation amount Fd” corresponding to the “positional deviation in the image” amount. The "positional deviation amount (grasping deviation amount)", which is the deviation amount from the position, is calculated.

(About work position shift, position shift in the image, shooting timing shift)
In the following description, the amount of deviation between the "position Pw of the work 40 (eg, the center position of the work 40)" and the "position of the hand 23" that is not actually imaged in the captured image Im is referred to as the "position of the work". Also called the "deviation" amount. The amount of "work misalignment" in the captured image Im corresponds to the misalignment amount (that is, the grip misalignment amount) which is the misalignment amount between the position Pw of the work 40 (eg, the center position of the work 40) and the position of the hand 23. do.

Further, the amount of deviation between the "position Pw of the work 40 (eg, the center position of the work 40)" and the "reference point Rb (eg, the center point of the captured image Im)" in the captured image Im is "in the image. Also called the amount of "misalignment". The amount of "positional deviation in the image" corresponds to the "first deviation amount Fd".

The image pickup device 33 performs imaging at a time when the position of the hand 23 and the detection position Pd do not match, so that the “position of the hand 23” and the “reference point Rb” that are not actually captured in the captured image Im are obtained. (For example, the center point of the captured image Im) ”. Therefore, the amount of deviation between the "position of the hand 23" that is not actually captured and the "reference point Rb (eg, the center point of the captured image Im)" in the captured image Im is also referred to as the "shooting timing deviation" amount. .. The "shooting timing shift" amount corresponds to the "second shift amount Sd" described later.

Here, the details will be described later with reference to FIG. 9, but the amount of “positional deviation in the image” can be decomposed into the amount of “work position deviation” and the amount of “shooting timing deviation”. The above-mentioned relationship between the amount of "misalignment of the work", the amount of "misalignment in the image", and the amount of "misalignment of shooting timing" is expressed as {"misalignment in the image" = "misalignment of the work". It may be expressed in the form of "amount +" amount of deviation in shooting timing "}. In other words, the "amount of deviation of the position Pw of the work 40 from the reference point Rb in the captured image Im" can be decomposed into the following two amounts of deviation in the captured image Im. That is, it can be decomposed into "amount of deviation of the position Pw of the work 40 from the position of the hand 23 in the captured image Im" and "amount of deviation of the position of the hand 23 from the reference point Rb in the captured image Im". ..

Here, at the detection time Td, the detection position Pd and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" coincide with each other. Therefore, when the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" match at the detection time Td, the following relationship occurs. Is established. That is, at the detection time Td, the "feedback position Pf of the servo control system 20" and the detection position Pd coincide with each other. In other words, when the position of the hand 23 and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" match at the detection time Td, the hand 23 is at the detection time Td. The position and the detection position Pd match. When the position of the hand 23 and the detection position Pd match at the detection time Td, the amount of "shooting timing deviation", which is the difference between the position of the hand 23 and the reference point Rb in the captured image Im, is "0". It becomes.

Then, {"position shift in the image" = "work position shift" amount + "shooting timing shift" amount}, so if the "shooting timing shift" amount is "0", {"in the image" "Position deviation" amount = "Work position deviation" amount}.

Therefore, when the position of the hand 23 and the detection position Pd match at the detection time Td, the control device 10 calculates the amount of "positional deviation in the image" (that is, the first deviation amount Fd). The amount of "work misalignment" (that is, the amount of misalignment) can be precisely specified.

As described above, compared with the method in which the control device 10 generates the captured image Im at the detection time Td without stopping the movement of the hand 23, thereby stopping the movement of the hand 23 and then generating the captured image Im. And the tact can be improved.

Further, the control device 10 generates the captured image Im at the detection time Td predicted that the position of the hand 23 and the detection position Pd match. Therefore, when the position of the hand 23 and the detection position Pd match at the detection time Td, the control device 10 calculates the amount of "positional deviation in the image" (that is, the first deviation amount Fd). The amount of "work misalignment" (that is, the amount of misalignment) can be precisely specified.

(Advantage over the method of providing a reference pin)
FIG. 7 is a diagram illustrating a method of coping with the “shift in shooting timing”. In each of FIG. 7A and FIG. 7B, the intersecting point of the alternate long and short dash line is "a reference point Rb corresponding to the detection position Pd in the captured image Im (eg, the center point of the captured image Im). ) ”Is shown. Further, the center position of the circle indicated by the dotted line indicates "the position of the hand 23 at the detection time Td", that is, "the feedback position Pf (actual position) of the servo control system 20 at the detection time Td". Further, the star mark indicates "position Pw of the work 40 (eg, the center position of the work 40)". Further, as in FIGS. 5 and 6, in FIG. 7, since the hand 23 is not actually hidden by the work 40 and imaged, the position of the hand 23 can be determined only by image analysis with respect to the captured image Im. I can't figure it out.

In FIG. 7A, a reference pin is provided in the vicinity of the hand 23 as a countermeasure against the “difference in shooting timing” that may occur when imaging is executed without stopping the movement of the work 40, and the work 40 is provided. It is a figure explaining the method of detecting the misalignment by taking an image of a reference pin together with.

In the example shown in FIG. 7A, the hand 23 is located at the center of the area surrounded by the reference pin. Therefore, the position of the hand 23 can be specified by the reference pin captured in the captured image Im, and the amount of deviation between the position of the hand 23 thus specified and the position of the work 40 is calculated. be able to.

The position of the hand 23 can also be specified by the reference pin by the method of "providing the reference pin in the vicinity of the hand 23 and imaging the reference pin together with the work 40", and therefore, the amount of deviation between the position of the hand 23 and the position of the work 40. That is, the amount of misalignment can be calculated.

Further, in the method of "providing a reference pin in the vicinity of the hand 23 and imaging the reference pin together with the work 40", the captured image Im required for calculating the position shift amount (grasping shift amount) is moved by the work 40. It can be generated without stopping. Therefore, the method of "providing the reference pin in the vicinity of the hand 23 and imaging the reference pin together with the work 40" raises the tact as compared with the method of "stopping the movement of the hand 23 and then generating the captured image Im". be able to.

However, as shown in FIG. 7A, the method of "providing a reference pin in the vicinity of the hand 23 and imaging the reference pin together with the work 40" is a reference provided in the vicinity of the hand 23 in addition to the work 40. It is also necessary to image the pin. Therefore, in the method of "providing a reference pin in the vicinity of the hand 23 and imaging the reference pin together with the work 40", the imaging range to be imaged by the image pickup apparatus 33 must be expanded as compared with the method in which the reference pin is not provided. As a result, the pixel resolution of the captured image Im tends to decrease.

Further, in general, the depth of field of the image pickup apparatus 33 is not so deep. As shown in FIG. 7A, when the work 40 is to be placed on a substrate or the like, there is a possibility that other members on the substrate may interfere with the reference pin.

Therefore, the control device 10 (particularly, the detection time determination unit 1160 in FIG. 1) sets the position of the hand 23 and the detection position Pd in order to generate the captured image Im that can calculate the amount of misalignment without providing the reference pin. The captured image Im is generated at the time (detection time Td) predicted to match. Specifically, the control device 10 causes the image pickup device 33 to perform imaging at the detection time Td.

When the position of the hand 23 and the detection position Pd match at the detection time Td, the “misalignment between the position Pw of the work 40 and the position of the hand 23 (that is, the misalignment)” is the “deviation of the work 40 in the captured image Im”. Corresponds to the deviation between the position Pw and the reference point Rb.

Therefore, the control device 10 uses the captured image Im, which can calculate the amount of misalignment, as a reference by generating the captured image Im at the detection time Td, which is the time predicted that the position of the hand 23 and the detection position Pd match. It can be generated without providing a pin. Since the control device 10 can generate an imaged image Im capable of calculating the amount of misalignment without providing a reference pin, the reference pin and other members are used as described with reference to FIG. 7A. Interference can be avoided.

Further, since the control device 10 does not need to provide the reference pin in the vicinity of the hand 23, the size of the hand 23 can be suppressed. In particular, the control device 10 can suppress the risk of the hand 23 interfering with other members or the like by using the hand 23, which is smaller than the case where the reference pin is provided in the vicinity.

Further, when the position of the hand 23 and the detection position Pd match at the detection time Td, the position of the hand 23 and the reference point Rb (eg, the center point of the captured image Im) coincide with each other in the captured image Im. In general, the position of the hand 23 and the position Pw of the work 40 (eg, the center position of the work 40) are unlikely to deviate significantly, so that the work 40 is arranged around the reference point Rb in the captured image Im. For example, it will be arranged in the substantially center of the captured image Im.

Therefore, the control device 10 can increase the ratio of the captured region of the work 40 to the entire captured image Im as compared with the captured image Im in which the work 40 is not arranged substantially in the center, that is, the work 40 is enlarged. It is possible to generate the captured image Im imaged by the above. Therefore, the control device 10 can perform high-precision image analysis with improved pixel resolution for the captured image Im with respect to the captured image Im captured by the work 40 magnified.

For the captured image Im, the required imaging range is determined by the size of the work 40 (the area of the surface on which the work 40 is photographed) and the assumed “positional deviation (grasping deviation)”.

(Occurrence of servo position fluctuation)
As described with reference to FIG. 7, when the captured image Im can be generated at the timing when the amount of “shooting timing shift” is “0”, the “work position” is obtained only by image analysis with respect to the captured image Im. The amount of "deviation" can be calculated accurately.

However, in reality, the "feedback position Pf of the servo control system 20 at the detection time Td (specifically, the" position of the hand 23 at the detection time Td ")" and the detection position Pd do not always match. Not exclusively. That is, the "target position Pt in consideration of the response delay time Ds of the servo control system 20 at the detection time Td" and the "feedback position Pf at the detection time Td" do not always match. Specifically, even if the response delay time Ds of the servo control system 20 is taken into consideration, the target position Pt and the feedback position Pf of the servo control system 20 do not always match at each time.

In the following description, the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" do not match at each time ( (Shifting) is also referred to as "servo position fluctuation".

FIG. 8 is a diagram showing an example of an operation profile when the detection position Pd is set to “100”. Specifically, (A) of FIG. 8 shows the target position of the servo control system 20 in consideration of the “response delay time Ds of the servo control system 20” at each time when the detection position Pd is “100”. "Pt" and "the target speed of the servo control system 20 corresponding to this" are shown. Further, FIG. 8B shows the case where the detection position Pd is “100” with respect to the “target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20” at each time. The amount of deviation of the "feedback position Pf of the servo control system 20" is shown.

When the detection position Pd is set to "100", the "feedback position Pf of the servo control system 20" with respect to the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at each time. The amount of deviation is within the following range. It is within the range of "−0.005 mm (that is, −5 μm)” to “+0.005 mm (that is, +5 μm)”.

As shown in FIG. 8B, the feedback position Pf of the servo control system 20 at each time of the servo control system 20 is the servo control system 20 even if the response delay time Ds of the servo control system 20 is taken into consideration. , Does not completely match the target position Pt at each time. That is, the position of the hand 23 at each time does not completely match the target position Pt of the servo control system 20 even if the response delay time Ds of the servo control system 20 is taken into consideration.

Here, as described above, at the detection time Td, the “target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20” coincides with the detection position Pd. Then, at the detection time Td, "the target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" and "the feedback position Pf of the servo control system 20 (that is, the position of the hand 23)". Do not match. Therefore, at the detection time Td, the position of the hand 23 does not completely coincide with the detection position Pd. Therefore, in the captured image Im, the position of the hand 23 (which is not actually captured) cannot be regarded as matching the reference point Rb, that is, the amount of "shooting timing deviation" cannot be regarded as "0". ..

(Effect of servo position fluctuation on captured image)
FIG. 9 is a diagram for explaining that it is necessary to consider “difference in shooting timing” in order to specify the amount of misalignment (amount of grip misalignment). In each of FIGS. 9A and 9B, the intersecting point of the alternate long and short dash line is "a reference point Rb corresponding to the detection position Pd in the captured image Im (eg, the center point of the captured image Im). ) ”Is shown. The center position of the circle shown by the dotted line indicates "the position of the hand 23 at the detection time Td", that is, "the feedback position Pf of the servo control system 20 at the detection time Td". The asterisk indicates "position Pw of the work 40 (eg, the center position of the work 40)".

In the captured image Im shown in FIG. 9, the solid line arrow indicates "the deviation between the position Pw of the work 40 and the reference point Rb in the captured image Im" (amount), that is, the amount of "positional deviation in the image". Shows. Further, the dotted arrow indicates "the deviation between the position Pw of the work 40 and the" position of the hand 23 at the detection time Td "" (amount), that is, indicates the amount of "position deviation of the work". Further, the alternate long and short dash arrow indicates "the deviation between the" position of the hand 23 at the detection time Td "and the reference point Rb" (amount), that is, the amount of "deviation in shooting timing".

Further, as in FIGS. 5, 6 and 7, in FIG. 9, since the hand 23 is not actually hidden by the work 40 and imaged, the hand 23 is obtained only by image analysis of the captured image Im. It is not possible to know the position of.

In the captured image Im shown in FIG. 9A, the center position of the circle indicated by the dotted line (that is, the position of the hand 23) coincides with the reference point R (that is, the detection position Pd) where the two-dot chain line intersects. There is. That is, (A) of FIG. 9 shows the captured image Im without "shift in shooting timing".

In the captured image Im shown in FIG. 9A, the amount of "positional deviation of the work" corresponds to the amount of "positional deviation in the image". That is, the amount of deviation between the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line corresponds to the amount of deviation between the star mark and the reference point R.

That is, when there is no "difference in shooting timing", the control device 10 can calculate the amount of "positional deviation in the image" in the captured image Im by image analysis with respect to the captured image Im, and the calculated "position in the image". The "shift" amount is equal to the "work position shift" amount.

Here, as described above, the misalignment amount (grasping misalignment amount), which is the amount of "misalignment between the position Pw of the work 40 and the position of the hand 23 (feedback position Pf) at the detection time Td", is the "misalignment amount" in the captured image Im. Corresponds to the amount of "work misalignment".

Therefore, when there is no "misalignment of shooting timing", the control device 10 can calculate the amount of misalignment from the "amount of" misalignment in the image "in the captured image Im" specified by image analysis.

In the captured image Im shown in FIG. 9B, the center position of the circle indicated by the dotted line and the reference point R at which the two-dot chain line intersects are deviated. That is, FIG. 9B shows the captured image Im in which the amount of “shooting timing shift” is not “0” (in other words, “shooting timing shift” has occurred).

In the captured image Im shown in FIG. 9B, the amount of "work position shift" does not match the amount of "position shift in the image". That is, the amount of deviation between the star mark (that is, the position Pw of the work 40) and the center position of the circle indicated by the dotted line does not match the amount of deviation between the star mark and the reference point R.

Therefore, it is not possible to calculate the amount of "work position shift" in the captured image Im only by calculating the amount of "position shift in the image" in the captured image Im. Therefore, it is not possible to specify the "positional deviation amount (grasping deviation amount)" corresponding to the "work position deviation" amount in the captured image Im.

The relationship established in the captured image Im, {the amount of "positional deviation in the image" can be decomposed into the amount of "work position deviation" and the amount of "shooting timing deviation"} is shown in FIG. 9 (B). ) Also shown. Therefore, when a "shooting timing shift" occurs, in order to specify the "work position shift" amount in the captured image Im, the "position shift in the image" amount and the "shooting timing shift" amount are set. Need to calculate. That is, when the position of the hand 23 and the detection position Pd at the detection time Td deviate from each other, in order to specify the "positional deviation amount", the first deviation amount Fd corresponding to the "positional deviation amount in the image" and " It is necessary to calculate the second deviation amount Sd corresponding to the "image timing deviation" amount.

FIG. 10 is a diagram for one-dimensionally explaining the influence of the “shooting timing shift” on the position shift (grasping shift). In each of (A) of FIG. 10 and (B) of FIG. 10, the solid line arrow indicates "the deviation between the position Pw of the work 40 and the detection position Pd at the detection time Td" (amount) (that is, the first deviation amount). Fd) is shown, that is, it corresponds to the amount of "positional deviation in the image" in the captured image Im. Further, the dotted arrow indicates "the deviation between the position Pw of the work 40 and the position (feedback position Pf) of the hand 23 at the detection time Td" (amount) (that is, the amount of displacement), that is, in the captured image Im. Corresponds to the amount of "work misalignment". Further, the alternate long and short dash arrow indicates "the deviation between the position of the hand 23 and the reference point Rb at the detection time Td" (amount) (the second deviation amount Sd described later), that is, the "shooting timing" in the captured image Im. Corresponds to the amount of "deviation".

As shown in FIG. 10A, when "the position of the hand 23 (feedback position Pf) and the detection position Pd match at the detection time Td", the misalignment amount (grasping misalignment amount) is the first misalignment. Matches the quantity Fd. That is, when there is no "shift in shooting timing", the amount of "shift in position of the work" corresponds to the amount of "shift in position in the image".

Therefore, when there is no "misalignment of shooting timing", the control device 10 corresponds to the amount of misalignment (grasping misalignment) by calculating the amount of "misalignment in the image" in the captured image Im by image analysis. The amount of "work misalignment" can be specified. In other words, when "the position of the hand 23 and the detection position Pd match at the detection time Td", the control device 10 can specify the misalignment amount (grasping misalignment amount) from the first misalignment amount Fd. ..

As shown in FIG. 10B, when "the position of the hand 23 (feedback position Pf) and the detection position Pd do not match at the detection time Td", the misalignment amount (grasping misalignment amount) is the first misalignment. Does not match the quantity Fd. That is, when there is a "shift in shooting timing", the amount of "shift in position of the work" does not match the amount of "shift in position in the image".

Therefore, when there is a "misalignment of shooting timing", the control device 10 corresponds to the amount of misalignment (grasping misalignment) simply by calculating the amount of "misalignment in the image" in the captured image Im by image analysis. The amount of "work misalignment" cannot be specified. In other words, when "the position of the hand 23 and the detection position Pd do not match at the detection time Td", the control device 10 specifies the misalignment amount (grasping misalignment amount) only from the first misalignment amount Fd. I can't.

As shown in FIG. 10B, when there is a "shooting timing shift", it is necessary to calculate the size of the alternate long and short dash arrow in addition to the size of the solid arrow in order to specify the size of the dotted arrow. There is. In other words, when the position of the hand 23 and the detection position Pd deviate from each other at the detection time Td, in order to specify the amount of "work position shift", in addition to the "position shift in the image" amount, the "shooting timing" It is necessary to calculate the amount of "deviation".

Therefore, when there is a "shift in shooting timing", the control device 10 calculates the amount of "shift in shooting timing" in addition to the amount of "shift in position in the image" to obtain the amount of "shift in position of the work". Exactly identify. In other words, the control device 10 precisely specifies the position shift amount (grasping shift amount) by calculating the second shift amount Sd in addition to the first shift amount Fd. Then, the control device 10 realizes accurate position control of the work 40 by correcting the control for the servo control system 20 in consideration of the specified amount of "position deviation of the work".

(Servo position fluctuation when the moving distance is shortened)
Here, when the moving distance of the servo control system 20 (moving distance of the hand 23) is shortened, in other words, when the moving distance (carrying distance) of the work 40 by the servo control system 20 is shortened, the position of the servo control system 20 It is generally known that the fluctuation becomes large.

FIG. 11 is a diagram illustrating a situation in which the moving distance (transporting distance) of the work 40 is shortened. As shown in FIG. 11, as a measure for shortening the tact, the moving distance (transporting distance) of the work 40, that is, the moving distance of the hand 23 can be shortened. That is, the moving distance of the work 40 shown in FIG. 11 (B) is shorter than the moving distance of the work 40 shown in FIG. 11 (A). As a result, when the moving speed of the work 40 is the same, the time required to execute the work illustrated in FIG. 11 (B) is larger than the time required to execute the work illustrated in FIG. 11 (A). It gets shorter.

FIG. 12 is a diagram showing an example of an operation profile when the detection position Pd is set to “40”. Specifically, (A) of FIG. 12 shows the target position of the servo control system 20 in consideration of the “response delay time Ds of the servo control system 20” at each time when the detection position Pd is “40”. "Pt" and "the target speed of the servo control system 20 corresponding to this" are shown. Further, FIG. 12B shows the case where the detection position Pd is “40” with respect to the “target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20” at each time. The amount of deviation of the "feedback position Pf of the servo control system 20" is shown.

When the detection position Pd is set to "40", the "feedback position Pf of the servo control system 20" with respect to the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at each time. The amount of deviation is within the following range. It is within the range of "−0.2 mm (that is, −200 μm)” to “+0.2 mm (that is, +200 μm)”.

Compared to the "deviation amount when the detection position Pd is" 100 "" shown in FIG. 8 (B), the "deviation when the detection position Pd is" 40 "" shown in FIG. 12 (B). "Amount" is large. That is, the “deviation amount when the detection position Pd is“ 100 ”” shown in FIG. 8 (B) was within the range of “0.005 mm” to “+0.005 mm”. On the other hand, the “deviation amount when the detection position Pd is“ 40 ”” shown in FIG. 12 (B) is in the range of “−0.2 mm” to “+0.2 mm”.

As shown in FIG. 12A, when the movement distance of the hand 23 is shortened, the operation profile becomes a triangular wave, and the feedback position Pf is set to "the target of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20". It becomes more difficult to follow the "position Pt".

(Differences in the effect of "shooting timing shift" due to differences in pixel resolution)
FIG. 13 is a diagram illustrating a difference in the influence of “difference in shooting timing” due to a difference in pixel resolution. In each of FIG. 13A and FIG. 13B, the intersecting point of the alternate long and short dash line is "a reference point Rb corresponding to the detection position Pd in the captured image Im (eg, the center point of the captured image Im). ) ”Is shown. The center position of the circle shown by the dotted line indicates "the position of the hand 23 at the detection time Td", that is, "the feedback position Pf of the servo control system 20 at the detection time Td". Further, similarly to FIG. 5 and the like, in FIG. 13, the hand 23 is not actually hidden by the work 40 and imaged.

As shown in FIG. 13, when the image of the work 40 captured in the captured image Im is enlarged, in other words, the captured image Im in which the work 40 is enlarged is generated and the pixel resolution is increased, the “servo position fluctuation” is obtained. The influence of "is increased. The "servo position fluctuation" appears as the amount of "shooting timing shift" in the captured image Im.

Specifically, when the pixel resolution is larger than the "servo position fluctuation" amount (that is, the "shooting timing deviation" amount in the captured image Im), the "work position deviation" amount (work position deviation) of the "servo position fluctuation" amount ( That is, the influence on the misalignment amount (grasping misalignment amount) is small. For example, when the required accuracy is "100 μm", the pixel resolution is "10 μm", and the amount of "servo position fluctuation" is "± 5 μm" which is smaller than the pixel resolution of "10 μm", the amount of "servo position fluctuation" is The effect on the amount of "work misalignment" can be ignored.

On the other hand, when the pixel resolution is equal to or less than the "servo position fluctuation" amount, the effect of the "servo position fluctuation" amount on the "work position deviation" amount (that is, the position deviation amount (grasping deviation amount)) is big. For example, when the required accuracy is "10 μm", the pixel resolution is "1 μm", and the amount of "servo position fluctuation" is "± 5 μm" which is equal to or greater than the pixel resolution of "1 μm", the "servo position fluctuation" amount is "± 5 μm". The effect on the amount of "work misalignment" cannot be ignored.

That is, if the amount of "servo position fluctuation" does not change, the effect of the "servo position fluctuation" amount on the "work position deviation" amount can be ignored if the pixel resolution is larger than the "servo position fluctuation" amount. , When the pixel resolution is less than or equal to the amount of "servo position fluctuation", it cannot be ignored.

When the pixel resolution is less than or equal to the "servo position fluctuation" amount (that is, the "shooting timing shift" amount in the captured image Im), a slight "servo position fluctuation" when moving the hand 23 is the cause. It becomes impossible to precisely specify the amount of "work misalignment". As a result, it becomes impossible to "move the work 40 to a desired position with high accuracy in consideration of the amount of misalignment (grasping misalignment) corresponding to the amount of" misalignment of the work "". That is, as the pixel resolution is increased, the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at each time. The deviation cannot be ignored.

("Work position shift" specified in consideration of "servo position fluctuation")
FIG. 14 explains the deviation between the “feedback position Pf of the servo control system 20” and the “target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20” at the detection time Td. It is a figure. Specifically, FIG. 14 shows (B) of FIG. 8 and an enlarged view of (B) of FIG. 8 near the detection time Td. In the enlarged view, the deviation (amount) between the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at the detection time Td. Is indicated by a single point chain arrow.

As described above, when there is a "misalignment of shooting timing", in order to precisely specify the amount of "misalignment of the work", in addition to the amount of "misalignment in the image" in the captured image Im, It is necessary to calculate the amount of "shooting timing shift" in the captured image Im.

As described above, the amount of "shooting timing shift" is the "position of the hand 23 (that is, the feedback position Pf of the servo control system 20)" and the "reference corresponding to the detection position Pd" in the captured image Im. It is the amount of deviation from the point Rb (eg, the center point of the captured image Im). Further, at the detection time Td, the detection position Pd and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" coincide with each other.

Therefore, the amount of "shift in shooting timing" takes into consideration the "position of the hand 23 (that is, the feedback position Pf of the servo control system 20)" and the "response delay time Ds of the servo control system 20" at the detection time Td. Corresponds to the deviation from the target position Pt of the servo control system 20.

Therefore, the control device 10 (particularly, the second deviation amount calculation unit 1190 in FIG. 1) considers the "position of the hand 23" and the "response delay time Ds" at the detection time Td as the "displacement of shooting timing" amount. , The deviation from the target position Pt of the servo control system 20 ”is calculated. That is, the second deviation amount calculation unit 1190 considers the "feedback position Pf of the servo control system 20" and the "response delay time Ds" at the detection time Td as the amount of "deviation of the shooting timing" of the servo control system 20. The amount of deviation from the target position Pt ”is calculated. The amount of deviation between the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds" at the detection time Td is also referred to as "second deviation amount Sd". To.

Specifically, the second deviation amount calculation unit 1190 calculates the "second deviation amount Sd" indicated by the alternate long and short dash arrow in the enlarged view of FIG.

The contents described with reference to FIGS. 9 to 14 can be summarized as follows. That is, the control device 10 (particularly, the second shift amount calculation unit 1190 in FIG. 1) calculates the second shift amount Sd corresponding to the “shooting timing shift” amount in the captured image Im. Specifically, the second deviation amount calculation unit 1190 sets the second deviation amount Sd to "the target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20 at the detection time Td". And the amount of "deviation from the feedback position Pf of the servo control system 20" is calculated.

Further, the control device 10 (particularly, the first deviation amount calculation unit 1170 in FIG. 1) determines "the amount of deviation between the position Pw of the work 40 and the reference point Rb in the captured image Im" by image analysis with respect to the captured image Im. Calculate a certain amount of "misalignment in the image". Then, the first deviation amount calculation unit 1170 specifies the first deviation amount Fd corresponding to the "positional deviation in the image" amount.

The control device 10 has a “shooting timing shift” amount and an “image” based on the relational expression of {“position shift in the image” = “work position shift” amount + “shooting timing shift” amount}. The amount of "work misalignment" is calculated from the amount of "misalignment within". That is, the control device 10 calculates the position deviation amount (grasping deviation amount) from the second deviation amount Sd and the first deviation amount Fd.

§2. Configuration Example The control device 10 whose outline has been described so far will be described in detail with reference to FIG. 1.

FIG. 1 is a diagram showing a configuration example of the control device 10. As functional blocks, the control device 10 includes, for example, a target trajectory acquisition unit 1110 that acquires a target trajectory Tt, a position command generation unit 1120 that generates a target position Pt for each time from the target trajectory Tt, and a corrected target position aPt. It includes a position command correction unit 1130 for calculation. Further, as functional blocks, the control device 10 includes, for example, a first deviation amount calculation unit 1170 for calculating the first deviation amount Fd, a feedback position calculation unit 1180 for calculating the second deviation amount Sd, and a second deviation amount calculation unit. It is equipped with 1190. Further, the control device 10 includes, for example, a response delay time calculation unit 1150 for calculating the response delay time Ds of the servo control system 20 and a detection time determination unit 1160 for determining the detection instruction time aTd as functional blocks. .. In addition, the control device 10 includes, for example, a command value generation unit 1140 that generates a command value Cm from the corrected target position aPt and a communication unit 1200 that executes communication with the servo control system 20 and the like as functional blocks. ing.

In addition to each of the above-mentioned functional blocks, the control device 10 may have, for example, the following configuration (functional block). That is, the control device 10 considers the actual position (feedback position Pf) of the servo control system 20 for each time and the target position Pt of the servo control system 20 for each time (particularly, the response delay time Ds of the servo control system 20). A servo control unit or the like that matches the target position Pt) may be provided. In order to ensure the conciseness of the description, the configuration of the control device 10 which is not directly related to the present embodiment is omitted from the description and the block diagram. However, according to the actual situation of implementation, the control device 10 may have these omitted configurations.

The above-mentioned functional block included in the control device 10 is, for example, a storage device (storage unit 1300) in which a CPU (central processing unit) or the like is realized by a ROM (read only memory), an NVRAM (non-Volatile random access memory), or the like. It can be realized by reading the program stored in the memory into a RAM (random access memory) (not shown) or the like and executing the program. First, the details of the functional blocks other than the storage unit will be described below.

(About functional blocks other than the storage unit)
The target trajectory acquisition unit 1110 receives target trajectory data (target trajectory Tt) from the outside (for example, a user), and outputs the received target trajectory Tt to the position command generation unit 1120.

The position command generation unit 1120 generates a “target position Pt for each control cycle Cc” from the target trajectory Tt, and outputs the generated “target position Pt for each control cycle Cc” to the position command correction unit 1130.

The position command correction unit 1130 acquires the "target position Pt for each control cycle Cc" from the position command generation unit 1120, acquires the first deviation amount Fd from the first deviation amount calculation unit 1170, and acquires the second deviation amount calculation unit. The second deviation amount Sd is acquired from 1190. Then, the position command correction unit 1130 generates a “corrected target position aPt for each control cycle Cc” in which the “target position Pt for each control cycle Cc” is corrected by the first deviation amount Fd and the second deviation amount Sd. The position command correction unit 1130 outputs the generated “corrected target position aPt for each control cycle Cc” to the command value generation unit 1140. Further, the position command correction unit 1130 outputs the “target position Pt for each control cycle Cc” to the detection time determination unit 1160 and the second deviation amount calculation unit 1190.

The command value generation unit 1140 acquires the “corrected target position aPt for each control cycle Cc” from the position command correction unit 1130, and acquires the “response delay time Ds of the servo control system 20” from the response delay time calculation unit 1150. .. The command value generation unit 1140 considers the “response delay time Ds of the servo control system 20” from the “corrected target position aPt for each control cycle Cc” and “command value for each control cycle Cc for the servo control system 20”. Generate "Cm". The command value generation unit 1140 outputs the generated "command value Cm for each control cycle Cc for the servo control system 20" to the communication unit 1200, particularly to the command unit 1210.

For example, in the "corrected target position aPt for each control cycle Cc" acquired from the position command correction unit 1130, if the corrected target position aPt (n) at the time T (n) is P (n), a command value is generated. The unit 1140 generates the following command value Cm. That is, the command value generation unit 1140 sets the corrected target position aPt (n) to P (n) at the “time retroactive from the time T (n) to the“ response delay time Ds of the servo control system 20 ””. Generate Cm.

Here, when the control device 10 controls a plurality of servo control systems 20, the command value generation unit 1140 executes the following processing in order to synchronize the control results (control amount) of the plurality of servo control systems 20. .. That is, for each of the plurality of servo control systems 20, the time from when each of the plurality of servo drivers 21 receives the command value Cm until the corresponding servomotor 22 responds (response delay time Ds) is a plurality of times. It may be different for each of the servo control systems 20. Therefore, the command value generation unit 1140 generates a command value Cm for each of the plurality of servo control systems 20 in consideration of the response delay time Ds of each of the plurality of servo control systems 20.

Specifically, the command value generation unit 1140 controls the servo from the "corrected target position aPt for each control cycle Cc" in consideration of the "response delay time Ds (A) of the servo control system 20 (A)". A command value Cm (A) for each control cycle Cc for the system 20 (A) is generated. The command value generation unit 1140 considers the “response delay time Ds (B) of the servo control system 20 (B)” from the “corrected target position aPt for each control cycle Cc” to the servo control system 20 (B). The command value Cm (B) for each control cycle Cc is generated. The command value generation unit 1140 considers the “response delay time Ds (C) of the servo control system 20 (C)” from the “corrected target position aPt for each control cycle Cc” to the servo control system 20 (C). The command value Cm (C) for each control cycle Cc is generated. The command value generation unit 1140 considers the “response delay time Ds (D) of the servo control system 20 (D)” from the “corrected target position aPt for each control cycle Cc” to the servo control system 20 (D). The command value Cm (D) for each control cycle Cc is generated.

By generating command values Cm for each of the plurality of servo control systems 20 in consideration of different response delay times Ds in each of the plurality of servo control systems 20, the command value generation unit 1140 may use the plurality of servo control systems 20. The control results of each of the above can be synchronized.

The response delay time calculation unit 1150 acquires a servo parameter indicating the control characteristics of the servo control system 20 (particularly, the servo driver 21), and calculates "response delay time Ds of the servo control system 20" from the acquired servo parameters. .. The response delay time calculation unit 1150 outputs the calculated "response delay time Ds of the servo control system 20" to the command value generation unit 1140, the detection time determination unit 1160, and the second deviation amount calculation unit 1190.

The response delay time calculation unit 1150 may calculate the response delay time Ds of the servo control system 20 by using the position loop gain of the servo driver 21 as a servo parameter indicating the control characteristics of the servo control system 20. For example, the response delay time calculation unit 1150 may use the response delay time Ds (A) of the servo control system 20 (A) as the reciprocal of the position loop gain, which is one of the servo parameters of the servo driver 21 (A). The response delay time calculation unit 1150 may use the response delay time Ds (B) of the servo control system 20 (B) as the reciprocal of the position loop gain, which is one of the servo parameters of the servo driver 21 (B). The response delay time calculation unit 1150 may use the response delay time Ds (C) of the servo control system 20 (C) as the reciprocal of the position loop gain, which is one of the servo parameters of the servo driver 21 (C). The response delay time calculation unit 1150 may use the response delay time Ds (D) of the servo control system 20 (D) as the reciprocal of the position loop gain, which is one of the servo parameters of the servo driver 21 (D).

The detection time determination unit 1160 acquires the “target position Pt for each control cycle Cc” from the position command correction unit 1130, and acquires the “response delay time Ds of the servo control system 20” from the response delay time calculation unit 1150. Further, the detection time determination unit 1160 acquires "information related to the detection position Pd" from the detection position table 1310 with reference to the storage unit 1300, and obtains "response delay time of the detection system 30" from the detector response delay time table 1320. Get "Dd". The detection time determination unit 1160 has "target position Pt for each control cycle Cc", "response delay time Ds of the servo control system 20", "information related to the detection position Pd", and "response delay time Dd of the detection system 30". ], The detection time Td and the detection instruction time aTd are calculated. Then, the detection time determination unit 1160 outputs the calculated detection instruction time aTd to the communication unit 1200, particularly to the command unit 1210.

Specifically, the detection time determination unit 1160 first detects from "target position Pt for each control cycle Cc", "response delay time Ds of servo control system 20", and "information related to detection position Pd". Calculate the time Td. That is, the detection time determination unit 1160 sets the time calculated as the time when the target position Pt and the detection position Pd coincide with each other in consideration of the “response delay time Ds of the servo control system 20” as the detection time Td.

Next, the detection time determination unit 1160 calculates the detection instruction time aTd from the detection time Td and the “response delay time Dd of the detection system 30”. That is, the detection time determination unit 1160 sets the time at which the detection time Td is corrected by the “response delay time Dd of the detection system 30” as the detection instruction time aTd.

For example, when the "response delay time Ds of the servo control system 20" does not exist and the time when the target position Pt and the detection position Pd match is the time T0, the detection time determination unit 1160 is as follows. , Detection time Td and detection instruction time aTd are calculated. That is, the detection time determination unit 1160 sets the time after the "response delay time Ds of the servo control system 20" from the time T0 when "the target position Pt and the detection position Pd match" as the detection time Td. Further, the detection time determination unit 1160 sets the time retroactive from the detection time Td to the “response delay time Dd of the detection system 30” as the detection instruction time aTd.

The first deviation amount calculation unit 1170 acquires the captured image Im from the communication unit 1200, particularly from the control amount acquisition unit 1220. The first deviation amount calculation unit 1170 executes image analysis on the captured image Im, calculates the amount of "positional deviation in the image" in the captured image Im, and calculates the "positional deviation in the image" amount. Therefore, the first deviation amount Fd is specified. The first deviation amount calculation unit 1170 outputs the specified first deviation amount Fd to the position command correction unit 1130.

Specifically, the first deviation amount calculation unit 1170 executes image analysis on the captured image Im, and sets the position Pw of the work 40 (eg, the center position of the work 40) and the reference point Rb in the captured image Im. The amount of "positional deviation in the image", which is the amount of deviation in the image, is calculated. Then, the first deviation amount calculation unit 1170 detects the position Pw of the work 40 at the detection time Td corresponding to the "position deviation in the image" amount from the calculated "position deviation in the image" amount. The first deviation amount Fd, which is the deviation amount from the position Pd, is specified.

However, the first deviation amount calculation unit 1170 may acquire the image analysis result of the captured image Im instead of the captured image Im from the communication unit 1200 (particularly, the control amount acquisition unit 1220), and in particular, the captured image. The amount of "misalignment in the image" in Im may be acquired. The first shift amount calculation unit 1170 only needs to be able to specify the first shift amount Fd from the "position shift in the image" amount in the captured image Im, and calculates the "position shift in the image" amount from the captured image Im. May be the first deviation amount calculation unit 1170 or the detection system 30.

That is, the control device 10 (particularly, the control amount acquisition unit 1220) receives the amount of "positional deviation in the image" calculated by the detection system 30 (for example, the image pickup control device 32) by image analysis on the image captured image Im. May be good. Then, the first deviation amount calculation unit 1170 may calculate the first deviation amount Fd from the amount of "positional deviation in the image" received by the image pickup control device 32.

The feedback position calculation unit 1180 acquires "feedback position Pf of the servo control system 20 for each control cycle Cc" from the communication unit 1200, particularly from the control amount acquisition unit 1220. The feedback position calculation unit 1180 calculates the "feedback position Pf at the detection time Td" from the "feedback position Pf of the servo control system 20 for each control cycle Cc" by interpolation calculation. The feedback position calculation unit 1180 outputs the calculated “feedback position Pf at the detection time Td” to the second deviation amount calculation unit 1190.

For example, when n is an "integer of 0 or more" and the detection time Td is the time between the "n" th control cycle Cc (n) and the "n + 1" th control cycle Cc (n + 1), the feedback position. The calculation unit 1180 executes the following processing. That is, the feedback position calculation unit 1180 first acquires the “feedback position Pf (n) in the control cycle Cc (n)” and the “feedback position Pf (n + 1) in the control cycle Cc (n + 1)”. Then, the feedback position calculation unit 1180 calculates the “feedback position Pf at the detection time Td” from the feedback position Pf (n) and the feedback position Pf (n + 1) by interpolation calculation. For example, the feedback position calculation unit 1180 "feedback position at the detection time Td" from the intersection of the straight line (or curve) connecting the feedback position Pf (n) and the feedback position Pf (n + 1) and the straight line indicating the detection time Td. Pf ”is calculated.

That is, the feedback position calculation unit 1180 "feedback position Pf at the detection time Td" by interpolation calculation from a plurality of "feedback positions Pf of the servo control system 20 for each control cycle Cc" acquired for each control cycle Cc. May be calculated.

The second deviation amount calculation unit 1190 acquires the "target position Pt for each control cycle Cc" from the position command correction unit 1130, and acquires the "response delay time Ds of the servo control system 20" from the response delay time calculation unit 1150. .. Further, the second deviation amount calculation unit 1190 acquires the “feedback position Pf at the detection time Td” from the feedback position calculation unit 1180.

The second deviation amount calculation unit 1190 is based on the "target position Pt for each control cycle Cc", the "response delay time Ds of the servo control system 20", and the "feedback position Pf at the detection time Td". Calculate Sd. The second deviation amount calculation unit 1190 outputs the calculated second deviation amount Sd to the position command correction unit 1130.

The second deviation amount calculation unit 1190 first calculates the "target position Pt at the detection time Td" from the "target position Pt for each control cycle Cc" and the "response delay time Ds of the servo control system 20". Next, the second deviation amount calculation unit 1190 calculates the second deviation amount Sd from the “target position Pt at the detection time Td” and the “feedback position Pf at the detection time Td”.

The communication unit 1200 periodically executes communication with each of the servo control system 20 and the detection system 30 as slaves, and includes a command unit 1210 and a control amount acquisition unit 1220.

The command unit 1210 acquires "command value Cm for each control cycle Cc for the servo control system 20" from the command value generation unit 1140, and acquires the detection instruction time aTd from the detection time determination unit 1160. The command unit 1210 outputs (transmits) control signals Cs (control instructions) including the command value Cm and the detection instruction time aTd to the slave servo control system 20 and the detection system 30 for each control cycle Cc.

The control amount acquisition unit 1220 acquires data indicating control results (eg, control amount and detection result) output by these slaves from the slave servo control system 20 and detection system 30 for each control cycle Cc (eg, control amount and detection result). Receive). That is, the control amount acquisition unit 1220 acquires information indicating "feedback position Pf of the servo control system 20 for each control cycle Cc" from the servo control system 20, and acquires the captured image Im from the detection system 30. The control amount acquisition unit 1220 transmits information indicating “feedback position Pf of the servo control system 20 for each control cycle Cc” to the feedback position calculation unit 1180, and transmits the captured image Im to the first deviation amount calculation unit 1170. Output.

The information indicating "feedback position Pf of the servo control system 20 for each control cycle Cc" is the time when the feedback position Pf is detected in addition to the "feedback position Pf of the servo control system 20 for each control cycle Cc". It may include information indicating a certain measured time Tm. In that case, the feedback position calculation unit 1180 acquires, for example, "feedback position Pf (n) in the control cycle Cc (n)" and "measured time Tm (n) in which the feedback position Pf (n) is detected". .. Further, the feedback position calculation unit 1180 acquires "feedback position Pf (n + 1) in the control cycle Cc (n + 1)" and "measured time Tm (n + 1) when the feedback position Pf (n + 1) is detected". Then, the feedback position calculation unit 1180 obtains the "feedback position Pf at the detection time Td" from the feedback position Pf (n) at the actual measurement time Tm (n) and the feedback position Pf (n + 1) at the actual measurement time Tm (n + 1). calculate.

Further, as described above, the control amount acquisition unit 1220 is calculated from the detection system 30 by the detection system 30 (for example, the image pickup control device 32) instead of the image image Im by image analysis on the image image Im. The amount of "misalignment" may be obtained. In that case, the control amount acquisition unit 1220 outputs the acquired “positional deviation in the image” amount to the first deviation amount calculation unit 1170.

(About the memory)
The storage unit 1300 is a storage device that stores various data used by the control device 10. The storage unit 1300 has (1) a control program executed by the control device 10, (2) an OS program, (3) an application program for executing various functions of the control device 10, and (4) the application. Various data to be read when the program is executed may be stored non-temporarily. The data of (1) to (4) above may be, for example, ROM (read only memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM), HDD (Hard Disc Drive), or the like. Stored in a non-volatile storage device. The control device 10 may include a temporary storage unit (not shown). The temporary storage unit is a so-called working memory that temporarily stores data used for calculation, calculation results, etc. in the process of various processes executed by the control device 10, and is a volatile storage device such as RAM (Random Access Memory). Consists of. Which data is stored in which storage device is appropriately determined from the purpose of use, convenience, cost, physical restrictions, and the like of the control device 10. The storage unit 1300 further stores a detection position table 1310 and a detector response delay time table 1320.

The detection position table 1310 stores "information related to the detection position Pd", specifically, "information for specifying the detection position Pd".

The "response delay time Dd of the detection system 30" is stored in the detector response delay time table 1320.

In addition to the detection position table 1310 and the detector response delay time table 1320, the storage unit 1300 may store servo parameters indicating the control characteristics of the servo control system 20 (particularly, the servo driver 21). In particular, the storage unit 1300 may store servo parameters indicating the control characteristics of each of the plurality of servo control systems 20 (particularly, the servo driver 21).

(Arrangement of control devices)
The contents described so far using FIGS. 1 to 14 can be organized as follows. That is, the control device 10 is a control device that outputs the command value Cm calculated from the target trajectory Tt to the servo control system 20. The control device 10 includes a first deviation amount calculation unit 1170, a second deviation amount calculation unit 1190, and a command value generation unit 1140.

The first deviation amount calculation unit 1170 determines the position Pw of the work 40 whose position is controlled by the servo control system 20 from the detection result (that is, the captured image Im) of the image pickup device 33 (detection device) at the detection time Td. The first deviation amount Fd, which is the deviation amount from the detection position Pd, is calculated. Here, the detection time Td is a detection position where the target position Pt calculated from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20 is the “position where the image pickup apparatus 33 detects the detection target”. It is a time that matches Pd.

The second deviation amount calculation unit 1190 "is a target position calculated in consideration of" the feedback position Pf of the servo control system 20 at the detection time Td "and" the response delay time Ds of the servo control system 20 at the detection time Td ". The second deviation amount Sd, which is the deviation amount from "Pt", is calculated.

The command value generation unit 1140 has corrected the “target position Pt calculated from the target trajectory Tt” by the first deviation amount Fd and the second deviation amount Sd, the corrected target position aPt, and the response delay of the servo control system 20. The command value Cm is generated from the time Ds.

According to the above configuration, the control device 10 has the corrected target position aPt obtained by correcting the “target position Pt calculated from the target trajectory Tt” by the first deviation amount Fd and the second deviation amount Sd, and the servo control system. The command value Cm is generated by the response delay time Ds of 20.

Here, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the feedback position Pf completely matches the detection position Pd at the detection time Td. It will be. Therefore, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the amount of deviation of the position Pw of the work 40 from the feedback position Pf (that is, the position deviation). The amount) can be specified only from the first deviation amount Fd. That is, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the misalignment amount (grasping misalignment amount) is only from the first misalignment amount Fd. Can be identified.

However, in reality, at the detection time Td, the feedback position Pf and the "target position Pt considering the response delay time Ds" may not completely match.

Therefore, the control device 10 considers the second deviation amount Sd in addition to the first deviation amount Fd, so that the "deviation amount of the position Pw of the work 40 from the feedback position Pf" at the detection time Td (that is,). , Amount of misalignment) is specified with high accuracy. Then, the control device 10 performs servo control with the corrected target position aPt obtained by correcting the "target position Pt calculated from the target trajectory Tt" by the specified "amount of deviation of the position Pw of the work 40 from the feedback position Pf". The command value Cm is generated from the response delay time Ds of the system 20.

Therefore, the control device 10 improves the accuracy of the position control of the work 40 by considering the deviation between the feedback position Pf of the servo control system 20 and the position Pw of the work 40 whose position is controlled by the servo control system 20. It has the effect of being able to do it.

Further, the control device 10 determines the first deviation amount Fd from the captured image Im which is the detection result at the detection time Td where "the target position Pt calculated in consideration of the response delay time Ds matches the detection position Pd". calculate. Therefore, the control device 10 does not need to stop the movement of the work 40 by the servo control system 20 in order to calculate the first deviation amount Fd.

Therefore, the control device 10 can perform high-speed position control on the work 40 at high speed, in other words, can realize high-speed and high-precision position control of the work 40.

In the control system 1, the image pickup control device 32 (detection control device) controls the detection operation (specifically, the image pickup operation) by the image pickup device 33, and the image pickup control device 32 together with the communication device 31 (communication control device). Perform communication between.

The control device 10 corrects the detection time Td in the control signal Cs transmitted to the communication device 31 for each control cycle Cc in consideration of the response delay time Dd of the detection system 30 (response delay time Dd of the image pickup device 33). Specify the detection instruction time aTd. By designating the detection instruction time aTd in the control signal Cs, the control device 10 causes the communication device 31 to output the detection instruction to the image pickup control device 32 at the detection instruction time aTd. Upon receiving the detection instruction from the communication device 31, the image pickup control device 32 transmits a detection trigger to the image pickup device 33, and causes the image pickup device 33 to perform a detection operation (specifically, an image pickup operation).

According to the above configuration, the control device 10 calculates the detection instruction time aTd, which is the time obtained by correcting the detection time Td by the response delay time Dd of the image pickup device 33. Then, the control device 10 designates the detection instruction time aTd in the control signal Cs output to the communication device 31 for each control cycle Cc.

The communication device 31 that has received the control signal Cs transmits a detection instruction to the image pickup control device 32 at the detection instruction time aTd, and the image pickup control device 32 that has received the detection instruction causes the image pickup device 33 to detect the detection target. .. Therefore, the time when the image pickup apparatus 33 detects the detection target is the time delayed from the detection instruction time aTd by the response delay time Dd of the image pickup apparatus 33, that is, the detection time Td.

Here, when the image pickup device 33 tries to perform an image pickup without considering the response delay time Dd of the image pickup device 33, the time when the image pickup device 33 actually executes the image pickup is the time when the image pickup device 33 executes the image pickup. Is delayed by the response delay time Dd of the image pickup apparatus 33 from the time instructed.

Therefore, the control device 10 calculates the detection instruction time aTd, which is the time obtained by correcting the detection time Td by the response delay time Dd of the image pickup device 33. Then, the control device 10 designates the detection instruction time aTd as the time for instructing the image pickup device 33 to execute the image pickup.

Therefore, the control device 10 designates the detection instruction time aTd in consideration of the response delay time Dd of the image pickup device 33 as the time for instructing the image pickup device 33 to execute the image pickup, so that the image pickup device 33 is instructed to perform the image pickup at the detection time Td. It has the effect of being able to perform imaging.

Further, the control device 10 specifies the detection instruction time aTd in the control signal Cs transmitted for each control cycle Cc. For example, the control device 10 sets the detection instruction time aTd to the control cycle Cc before the detection instruction time aTd. It is specified in the control signal Cs in.

Therefore, by designating the detection instruction time aTd in the control signal Cs, the control device 10 detects even if the detection instruction time aTd is not an integral multiple of the control cycle Cc which is the communication cycle with the communication device 31. It has the effect of being able to detect the detection target at time Td.

The control device 10 executes communication with the servo control system 20 every control cycle Cc. Then, the control device 10 (particularly, the feedback position calculation unit 1180) sets the “feedback position Pf of the servo control system 20 at the detection time Td” from the “feedback position Pf of the servo control system 20 for each control cycle Cc”. , Calculated by interpolation calculation.

According to the above configuration, the control device 10 calculates the "feedback position Pf of the servo control system 20 at the detection time Td" from the "feedback position Pf of the servo control system 20 for each control cycle Cc" by interpolation calculation. calculate.

For example, it is assumed that n is an "integer of 0 or more" and the detection time Td is a time between the "n" th control cycle Cc (n) and the "n + 1" th control cycle Cc (n + 1). In this case, the control device 10 calculates the "feedback position Pf of the servo control system 20 at the detection time Td" as follows. That is, the control device 10 first acquires the "feedback position Pf (n) in the control cycle Cc (n)" and the "feedback position Pf (n + 1) in the control cycle Cc (n + 1)" of the servo control system 20. do. Next, the control device 10 calculates the "feedback position Pf of the servo control system 20 at the detection time Td" from the feedback position Pf (n) and the feedback position Pf (n + 1) by interpolation calculation.

Therefore, even if the detection time Td is not an integral multiple of the control cycle Cc, which is the communication cycle with the servo control system 20, the control device 10 accurately "provides the servo control system 20 at the detection time Td. It has the effect of being able to calculate the "feedback position Pf".

The control device 10 outputs a command value Cm in consideration of the response delay time Ds of each of the plurality of servo control systems 20 to each of the plurality of servo control systems 20 synchronized with each other.

According to the above configuration, the control device 10 outputs a command value Cm in consideration of the response delay time Ds of each of the plurality of servo control systems 20 to each of the plurality of servo control systems 20 synchronized with each other.

Therefore, the control device 10 has the effect that a plurality of servo control systems 20 can be controlled in a state of being synchronized with each other to realize highly accurate position control of the work 40.

The control device 10 uses, for example, an image pickup device 33 as a detection device for detecting the amount of deviation between the position Pw of the work 40 and the detection position Pd, and specifically, the captured image Im generated by the image pickup device 33. The first deviation amount calculation unit 1170 is the deviation amount between the reference point Rb corresponding to the detection position Pd in the image captured image Im captured by the image pickup device 33 and the position Pw of the work 40 in the image captured image Im (that is, “in the image”. The first misalignment amount Fd is calculated from the "positional misalignment" amount).

According to the above configuration, the control device 10 calculates the first deviation amount Fd by the deviation amount between the reference point Rb (for example, the center position of the captured image Im) and the position Pw of the work 40 in the captured image Im. Then, the control device 10 sets the target position Pt on the servo control system 20 by the corrected target position aPt corrected by the first deviation amount Fd and the second deviation amount Sd and the response delay time Ds of the servo control system 20. Generate the command value Cm to be output.

Here, there is known an image analysis technique for specifying a position or the like of an image pickup target in an image captured image Im at high speed and with high accuracy.

Therefore, the control device 10 can realize high-speed and high-precision position control of the work 40 by the first deviation amount Fd calculated from the captured image Im with high speed and high accuracy and the second deviation amount Sd. Play.

Further, according to the above configuration, the control device 10 sets the time at which the target position Pt calculated from the target trajectory Tt in consideration of the response delay time Ds reaches the detection position Pd (that is, the detection time Td). The captured image Im is imaged. Therefore, in the captured image Im, the target position Pt calculated from the target trajectory Tt in consideration of the response delay time Ds and the reference point Rb (for example, the center position of the captured image Im) coincide with each other.

Here, the “target position Pt considering the response delay time Ds” at the detection time Td is calculated from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20. Therefore, at the detection time Td, the feedback position Pf and the "target position Pt considering the response delay time Ds" should be sufficiently close to each other. That is, when the feedback position Pf and the position Pw of the work 40 (for example, the center position of the work 40) are sufficiently close to each other, the position Pw of the work 40 should be sufficiently close to the detection position Pd at the detection time Td. Therefore, for example, when the center position of the captured image Im is set as the reference point Rb, the work 40 is arranged substantially in the center of the captured image Im.

Therefore, the control device 10 can reduce the inspection area for specifying the position Pw of the work 40 (for example, the center position of the work 40) in the captured image Im, and can realize high-speed image analysis processing. can.

Further, since the work 40 is arranged substantially in the center of the captured image Im, the captured region of the work 40 occupies a large proportion of the entire captured image Im as compared with the captured image in which the work 40 is not arranged substantially in the center. That is, the work 40 can be magnified and imaged. Therefore, the control device 10 can perform highly accurate image analysis on the captured image Im captured by the work 40 in an enlarged manner.

Therefore, the control device 10 realizes high-speed and high-precision image analysis for the captured image Im, and by using the result of this image analysis, it is possible to realize high-speed and high-precision position control of the work 40. Play.

Regarding the control device 10, the servo control system 20 includes a servo motor 22 that drives the axis of the manipulator that can change the position Pw of the work 40, and a servo driver 21 that controls the servo motor 22. The target position Pt and the feedback position Pf of the servo control system 20 are the target position Pt and the feedback position Pf of the hand 23, which is the grip portion of the manipulator, respectively.

According to the above configuration, in the control device 10, the detection time Td, that is, the target position Pt of the hand 23 calculated from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20 is the detection position. The first deviation amount Fd is calculated from the captured image Im at the time corresponding to Pd. Further, the control device 10 is composed of the feedback position Pf of the hand 23 at the detection time Td and the “target position Pt of the hand 23 calculated from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20”. , The second deviation amount Sd is calculated. Then, the control device 10 corrects the target position Pt by the first deviation amount Fd calculated from the captured image Im and the second deviation amount Sd for the hand 23 at the detection time Td, and obtains the corrected target position aPt. Generate. The control device 10 generates a command value Cm to be output to the servo control system 20 by the generated corrected target position aPt and the response delay time Ds of the servo control system 20.

Therefore, the control device 10 realizes highly accurate position control of the work 40 by the manipulator in consideration of the first deviation amount Fd at the detection time Td and the second deviation amount Sd for the hand 23 at the detection time Td. It has the effect of being able to do it.

For the control device 10, the manipulator executes a picking operation and a place operation of the work 40, and the first deviation amount Fd is from the detection position Pd of the position Pw of the work 40 held by the manipulator (particularly, the hand 23). The amount of deviation.

According to the above configuration, the control device 10 is based on the first deviation amount Fd and the second deviation amount Sd, which are "the deviation amount of the position Pw of the work 40 gripped by the manipulator from the detection position Pd". , The target position Pt is corrected, and the corrected target position aPt is generated. Then, the control device 10 generates a command value Cm to be output to the servo control system 20 by the corrected target position aPt and the response delay time Ds of the servo control system 20.

Here, even when the feedback position Pf and the “target position Pt calculated in consideration of the response delay time Ds” completely match, depending on the state of the work 40 gripped by the manipulator, the detection time Td The position Pw of the work 40 deviates from the detection position Pd. For example, when the manipulator grips the work 40 at a position on the right side of the center position of the work 40, the center position of the work 40 at the detection time Td shifts to the left side with respect to the detection position Pd. Similarly, when the manipulator grips the work 40 at a position on the left side of the center position of the work 40, the center position of the work 40 at the detection time Td shifts to the right side with respect to the detection position Pd.

Further, it is considered that the "deviation between the position Pw of the work 40 and the position of the hand 23" generated during the picking operation is often maintained until the place operation.

Therefore, the control device 10 identifies the "deviation between the position Pw of the work 40 and the position of the hand 23" that occurs during the picking operation, and identifies the "deviation between the position Pw of the work 40 and the position of the hand 23". The place position of the work 40 is controlled in consideration of.

Therefore, the control device 10 has the effect of being able to realize highly accurate position control of the work 40 in consideration of the state of the work 40 held by the manipulator.

For the control device 10, the hand 23 of the manipulator executes the picking operation by vacuum suction or magnetic suction.

According to the above configuration, the control device 10 is targeted by the first deviation amount Fd for the work 40 gripped by the hand 23 using vacuum suction or magnetic suction and the second deviation amount Sd for the hand 23. The position Pt is corrected, and the corrected target position aPt is generated. Then, the control device 10 generates a command value Cm to be output to the servo control system 20 by the corrected target position aPt and the response delay time Ds of the servo control system 20.

Here, compared to the case where the work 40 is gripped by a two-finger or five-finger type gripper (hand), when the work 40 is gripped by vacuum suction or magnetic suction, the work 40 is displaced from the center position. It is considered that there is a greater possibility that the work 40 will be gripped at the vertical position.

Therefore, in order to control the position of the work 40 gripped by the manipulator with high accuracy, it is necessary to consider "the deviation between the position Pw of the work 40 and the position of the hand 23" by using vacuum suction or magnetic suction. It becomes larger when gripping the work 40.

Therefore, the control device 10 has the effect that the servo control system 20 including the manipulator that executes the picking operation by vacuum suction or magnetic suction can be controlled to realize high-speed and high-precision position control of the work 40.

§3. Operation example (Overview of processing)
FIG. 15 is a flow chart illustrating an overall outline of the processing executed by the control device 10. FIG. 15 particularly eliminates the misalignment of the work 40 caused by the “misalignment between the position Pw of the work 40 moved by the servo control system 20 and the position of the servo control system 20” executed by the control device 10. Explains the outline of the process.

As shown in FIG. 15, in the control device 10, the detection time determination unit 1160 executes the detection instruction time determination process (S110). Then, the communication unit 1200 (particularly, the command unit 1210) transmits the detection instruction time aTd determined by the detection instruction time determination process (S120).

The communication unit 1200 (particularly, the control amount acquisition unit 1220) obtains the detection result of the detection system 30 (for example, the captured image Im) and the control result of the servo control system 20 (for example, the feedback position Pf for each control cycle Cc). Receive (S130). Then, the control amount acquisition unit 1220 notifies the first deviation amount calculation unit 1170 of the detected detection result of the received detection system 30, and also notifies the feedback position calculation unit 1180 of the received control result of the servo control system 20.

The first deviation amount calculation unit 1170 executes the first deviation amount calculation process using the detection result of the detection system 30 (S140). Further, the feedback position calculation unit 1180 and the second deviation amount calculation unit 1190 execute the second deviation amount calculation process using the control result of the servo control system 20 (S150).

The position command correction unit 1130 generates a corrected target position aPt in which the target position Pt is corrected by the first deviation amount Fd calculated in S140 and the second deviation amount Sd calculated in S150 (S160). Then, the command value generation unit 1140 generates a command value Cm from the corrected target position aPt in consideration of the response delay time Ds of the servo control system 20 (S170).

(About detection instruction time determination processing)
FIG. 16 is a flow chart illustrating an example of the detection instruction time determination process (S110) of FIG. As shown in FIG. 16, the detection time determination unit 1160 first calculates the target position Pt (t) for each time from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20 (S210). .. The detection time determination unit 1160 specifies a time at which the “target position Pt (t) in consideration of the response delay time Ds of the servo control system 20” and the detection position Pd coincide with each other as the detection time Td (S220). The detection time determination unit 1160 determines the detection instruction time aTd with respect to the detection time Td in consideration of the response delay time Dd of the detection system 30 (S230).

(About the first deviation amount calculation process and the second deviation amount calculation process)
FIG. 17 is a flow chart illustrating an example of each of the first deviation amount calculation process (S140) and the second deviation amount calculation process (S150) of FIG. Specifically, FIG. 17A is a flow chart for explaining an example of the first deviation amount calculation process, and FIG. 17B is a flow chart for explaining an example of the second deviation amount calculation process. Is.

As shown in FIG. 17A, the first deviation amount calculation unit 1170 first performs image analysis on the captured image Im at the detection time Td, and the position Pw of the work 40 in the captured image Im ( For example, the center position of the work 40) is specified (S310).

The first deviation amount calculation unit 1170 may use the specified "position Pw of the work 40 in the captured image Im" and the reference point Rb corresponding to the detected position Pd in the captured image Im (eg, the center of the captured image Im). The amount of deviation from "points)" (that is, the amount of "positional deviation in the image") is calculated (S320).

The first deviation amount calculation unit 1170 calculates the first deviation amount Fd, which is the “deviation amount between the detection position Pd and the position Pw of the work 40”, from the deviation amount calculated in S320 (S330).

As shown in FIG. 17B, the feedback position calculation unit 1180 first changes from the “feedback position Pf of the servo control system 20” for each control cycle Cc to the “feedback position of the servo control system 20 at the detection time Td”. Pf ”is calculated (S410). The feedback position calculation unit 1180 notifies the second deviation amount calculation unit 1190 of the calculated “feedback position Pf of the servo control system 20 at the detection time Td”.

The second deviation amount calculation unit 1190 calculates "the target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at the detection time Td (S420).

The second deviation amount calculation unit 1190 calculates the deviation amount between the feedback position Pf calculated in S410 and the target position Pt calculated in S420 as the second deviation amount Sd (S420). That is, the second deviation amount calculation unit 1190 is the "feedback position Pf of the servo control system 20" and the "target position Pt of the servo control system 20 in consideration of the response delay time Ds of the servo control system 20" at the detection time Td. The amount of deviation between and is calculated as the second amount of deviation Sd.

The processes executed by the control device 10 described with reference to FIGS. 15 to 17 can be organized as follows. That is, the control method executed by the control device 10 is a control method of the control device that outputs the command value Cm calculated from the target trajectory Tt to the servo control system 20. The control method includes a first deviation amount calculation step (S140 in FIG. 15), a second deviation amount calculation step (S150 in FIG. 15), and a command value generation step (S170 in FIG. 15).

As illustrated in FIG. 17A, the first deviation amount calculation step is from the detection position Pd of the position Pw of the work 40 whose position is controlled by the servo control system 20 from the captured image Im at the detection time Td. The first deviation amount Fd, which is the deviation amount of, is calculated. As described above, at the detection time Td, the “target position Pt calculated from the target trajectory Tt in consideration of the response delay time Ds of the servo control system 20” and the detection position Pd coincide with each other.

As illustrated in FIG. 17B, the second deviation amount calculation step is "calculated in consideration of the feedback position Pf of the servo control system 20 and the response delay time Ds of the servo control system 20 at the detection time Td. The second deviation amount Sd, which is the deviation amount from the “target position Pt” that has been set, is calculated.

In the command value generation step, the corrected target position aPt obtained by correcting the “target position Pt calculated from the target trajectory Tt” by the first deviation amount Fd and the second deviation amount Sd, and the response delay time Ds of the servo control system 20. From, the command value Cm is generated.

According to the above configuration, in the control method, the corrected target position aPt in which the target position Pt is corrected by the first deviation amount Fd and the second deviation amount Sd and the response delay time Ds of the servo control system 20 are used. The command value Cm to be output to the servo control system 20 is generated.

Here, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the feedback position Pf completely matches the detection position Pd at the detection time Td. It will be. Therefore, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the amount of deviation of the position Pw of the work 40 from the feedback position Pf (that is, the position deviation). The amount) can be specified only from the first deviation amount Fd. That is, when the feedback position Pf and the "target position Pt considering the response delay time Ds" completely match at the detection time Td, the misalignment amount (grasping misalignment amount) is only from the first misalignment amount Fd. Can be identified.

However, in reality, at the detection time Td, the feedback position Pf and the "target position Pt considering the response delay time Ds" may not completely match.

Therefore, in the control method, the "deviation amount of the position Pw of the work 40 from the feedback position Pf" at the detection time Td is determined by considering the second deviation amount Sd in addition to the first deviation amount Fd. Identify with high accuracy. Then, the control method includes a corrected target position aPt obtained by correcting "a target position Pt calculated from the target trajectory Tt" by the specified "amount of deviation of the position Pw of the work 40 from the feedback position Pf", and servo control. The command value Cm is generated from the response delay time Ds of the system 20.

Therefore, the control method improves the accuracy of the position control of the work 40 by considering the deviation between the feedback position Pf of the servo control system 20 and the position Pw of the work 40 whose position is controlled by the servo control system 20. It has the effect of being able to do it.

Further, in the control method, the first deviation amount Fd is calculated from the captured image Im at the detection time Td in which the target position Pt calculated in consideration of the response delay time Ds matches the detection position Pd. Therefore, in the control method, it is not necessary to stop the movement of the work 40 by the servo control system 20 in order to calculate the first deviation amount Fd.

Therefore, the control method has the effect of being able to execute high-precision position control on the work 40 at high speed, in other words, being able to realize high-speed and high-precision position control of the work 40.

§4. Modification Example Although an example in which the control device 10 controls a plurality of servo control systems 20 has been described so far, the number of servo control systems 20 controlled by the control device 10 may be one. Further, although an example has been described in which the detection device for detecting "the amount of deviation between the position Pw of the work 40 and the detection position Pd" is the image pickup device 33, it is essential that the detection device is the image pickup device 33. is not it. The control device 10 can calculate "the amount of deviation between the position Pw of the work 40 and the detection position Pd" from the detection device capable of detecting "the amount of deviation between the position Pw of the work 40 and the detection position Pd". It suffices if the result can be obtained. Further, although an example in which the hand 23 grips the work 40 and moves the work 40 has been described so far, it is not essential that the hand 23 grips the work 40. In the control system 1, the work 40 may move as the hand 23 moves, and the control device 10 may control the position Pw of the work 40 by controlling the position of the hand 23.

[Example of implementation by software]
The control block of the control device 10 (particularly, the target trajectory acquisition unit 1110, the position command generation unit 1120, the position command correction unit 1130, the command value generation unit 1140, the response delay time calculation unit 1150, the detection time determination unit 1160, the first deviation amount). The calculation unit 1170, the feedback position calculation unit 1180, the second deviation amount calculation unit 1190, and the communication unit 1200) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like. , May be realized by software.

In the latter case, the control device 10 includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes the program, thereby achieving the object of the present invention. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium", for example, a ROM (Read Only Memory) or the like, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

10 Control device 20 Servo control system 23 Hand 30 Detection system 31 Communication device (communication control device)
32 Imaging control device (detection control device)
33 Imaging device (detection device)
40 Work 1170 First deviation amount calculation unit 1190 Second deviation amount calculation unit 1140 Command value generation unit aPt Corrected target position aTd Detection instruction time Cc Control cycle Cm Command value Cs Control signal Dd Detection system response delay time Ds Servo control system Response delay time Fd First deviation amount Im Captured image Pd Detection position Pf Feedback position Pt Target position Rb Reference point Sd Second deviation amount S140 First deviation amount calculation step S150 Second deviation amount calculation step S170 Command value generation step Td detection Time Tt Target trajectory

Claims (9)

It is a control device that outputs the command value calculated from the target trajectory to the servo control system.
The detection device at the detection time, which is the time when the target position calculated from the target trajectory in consideration of the response delay time of the servo control system coincides with the detection position, which is the position where the detection device detects the detection target. From the detection result, the first deviation amount calculation unit that calculates the first deviation amount, which is the deviation amount from the detection position, of the position of the work whose position is controlled by the servo control system,
The second deviation amount for calculating the second deviation amount, which is the deviation amount between the feedback position at the detection time and the target position calculated in consideration of the response delay time at the detection time of the servo control system. Calculation unit and
A command value generation unit that generates the command value from the corrected target position obtained by correcting the target position calculated from the target trajectory by the first deviation amount and the second deviation amount and the response delay time. Prepare ,
A control signal that transmits the detection instruction time corrected for the detection time in consideration of the response delay time of the detection device to the communication control device that communicates with the detection control device that controls the detection operation by the detection device for each control cycle. Specified in
By causing the communication control device to output a detection instruction to the detection control device at the detection instruction time, the detection device is made to detect the detection target at the detection time.
Communication with the servo control system is executed every control cycle,
The feedback position of the servo control system at the detection time is a control device calculated by interpolation calculation from the feedback position of the servo control system for each control cycle . The control device according to claim 1, wherein a command value considering the response delay time of each of the plurality of servo control systems is output to each of the plurality of servo control systems synchronized with each other. The detection device is an image pickup device.
The first deviation amount calculation unit calculates the first deviation amount based on the deviation amount between the reference point corresponding to the detection position in the image captured by the imaging device and the position of the work in the captured image. The control device according to claim 1 or 2 . The servo control system includes a servomotor that drives a shaft of a manipulator that can change the position of the work, and a servodriver that controls the servomotor.
The control device according to any one of claims 1 to 3 , wherein the target position and the feedback position are the target position and the feedback position of the hand which is the grip portion of the manipulator, respectively. The manipulator executes the picking operation and the place operation of the work, and performs the picking operation and the place operation.
The control device according to claim 4 , wherein the first deviation amount is an deviation amount of the position of the work held by the manipulator from the detection position. The control device according to claim 5 , wherein the hand of the manipulator executes the picking operation by vacuum suction or magnetic suction. It is a control method of a control device that outputs a command value calculated from a target trajectory to a servo control system.
The detection device at the detection time, which is the time when the target position calculated from the target trajectory in consideration of the response delay time of the servo control system coincides with the detection position, which is the position where the detection device detects the detection target. From the detection result, the first deviation amount calculation step for calculating the first deviation amount, which is the deviation amount from the detection position, of the position of the work whose position is controlled by the servo control system,
The second deviation amount for calculating the second deviation amount, which is the deviation amount between the feedback position at the detection time and the target position calculated in consideration of the response delay time at the detection time of the servo control system. Calculation steps and
A command value generation step for generating the command value from the corrected target position obtained by correcting the target position calculated from the target trajectory by the first deviation amount and the second deviation amount and the response delay time. Including,
A control signal that transmits the detection instruction time corrected for the detection time in consideration of the response delay time of the detection device to the communication control device that communicates with the detection control device that controls the detection operation by the detection device for each control cycle. Specified in
By causing the communication control device to output a detection instruction to the detection control device at the detection instruction time, the detection device is made to detect the detection target at the detection time.
Communication with the servo control system is executed every control cycle,
The feedback position of the servo control system at the detection time is a control method calculated by interpolation calculation from the feedback position of the servo control system for each control cycle . An information processing program for operating a computer as the control device according to any one of claims 1 to 6 , wherein the information processing program for operating the computer as each part thereof. A computer-readable recording medium on which the information processing program according to claim 8 is recorded.

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