JP3092420B2 - Robot interference detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot interference detecting method for detecting the state of interference with surrounding structures and other robots when the robot operates.

[0002]

2. Description of the Related Art In recent years, many scenes in which robots are used as production equipment in factories have been seen.

[0003] The operation of this robot varies depending on the type of robot. As a typical example, the operation to be performed by the robot is previously taught (teaching), and the teaching operation is played back during actual operation. There is a teaching and playback system that is operating.

FIG. 5 is a block diagram for explaining a conventional robot controller using a teaching / playback method. This control device is roughly divided into a controller 10 for issuing data and operation commands necessary for the operation of the robot.
And a servo amplifier unit 20 for controlling a current required for the operation of the robot body in accordance with an operation command from the controller 10.

The controller 10 receives a signal for coordinating with the movement of a workpiece on the line from a central control device (not shown) or the like which controls the entire line on which the robot body 30 is installed. , A control unit 11 for performing control such as issuing an operation command to the robot, and a robot body 30
It has a teach data memory 12 in which teach data and parameters are previously taught, a position control CPU 13 for generating a speed command, and a sensor CPU 14 for generating position data and speed feedback data from a position detection signal from a robot. The servo amplifier unit 20 has a speed CPU 21 for generating a current command for controlling the motor of each axis of the robot from speed command data from the position control CPU 13 of the controller 10 and speed feedback from the sensor CPU 14, and a current control unit 22.

[0006] The operation of each unit includes the position data of the spatial coordinates where the robot is located from a certain point to a certain point as the teach data, and the speed at which the control unit 11 moves from a certain point to a certain point as a parameter. The operation target value is instructed by the position control CPU 13 from the stored position data and parameters in the teach data memory 12. In the position control CPU 13, the received target value and the sensor C
The difference between the current position data of the robot from the PU 14 per unit time is obtained, speed command data is created, and a command is sent to the speed control CPU. In the speed control CPU 21 receiving the speed command data, the speed control data and the sensor CPU 14
The current command data is created by taking the difference from the speed feedback data from the current command, and the current command data is subjected to a current limitation to command the current control unit 22. The current control unit 22 that has received the current command compares the current command data with a current detection signal (current value) from the robot body 30 and uses the difference as a current value as the PWM drive circuit 33 of the robot.
To supply. The sensor CPU 14 generates the current position data of the operating robot and the speed feedback data that is the actual operating speed by differentiating the current position data from the position detection signal from the robot.

In order to detect the value of the current flowing through the motor that operates the robot, a resistor is connected in series to both ends of the power supply of the motor, and the voltage at both ends is detected to detect the voltage value. A current detecting unit 31 for detecting a current value flowing to the motor through isolation is provided. Each axis of the robot is provided with a position such as a resolver (absolute sensor) 32 for detecting a position during operation. Detection means is provided.

In controlling such a conventional teaching / playback robot, the robot is operated not only to perform the work accurately, but also to a structure around the robot, for example, a partition for partitioning a work space. It must be operated so that it does not interfere with the work and panels required for the work, adjacent work equipment and other robots. For this purpose, teaching is performed so that the robot does not interfere with the surrounding structure during the teaching, so there is no significant interference that would stop the operation of the robot itself.
For some reason, there is a case where the robot is operating while making slight contact with the peripheral structure (the operation path of the robot interferes).

[0009] If a part of the robot rubs against the peripheral structure due to such slight contact, the paint on the peripheral structure or the contact portion of the robot is found to be peeled off. It is known which operation in the path has an interference part. Conventionally, the teach data in the operation path at that time is examined, an interference portion is estimated, and the teach data is changed so that no interference occurs, so that no interference occurs.

[0010]

However, in such conventional robot interference detection, it is possible to know which of the robot's operation paths interfered with the surrounding structures, It is not possible to specify the exact position of the interference at the same time, and when changing the teach data, it is performed by a rough change, an extra operation path is set, and efficient robot operation can be performed. As a result, there is a problem that productivity is reduced and interference with other peripheral structures occurs due to a change in the operation path.

Accordingly, an object of the present invention is to provide a robot interference detection method capable of accurately specifying an interference position when the robot interferes with a peripheral structure.

[0012]

According to the present invention, there is provided a robot for detecting an operation target value from pre-stored teach data and detecting the operation target value and the operation position of each axis of the robot. A position control unit that takes a difference from position data from the provided position detection unit and creates speed command data, an operation speed calculation unit that differentiates the position data and calculates speed feedback data of each axis of the robot, A speed control means for taking a difference between the speed command data and the speed feedback data to create current command data, and a robot for detecting a current flowing to a motor driving each axis of the robot with the current command data. takes the difference between the load current value current detecting means detects a current control means for outputting a current supplied to the respective axis drive motors of the robot A, a interference detection method for a robot which is operated by a robot controller for feedback controlling the operation of the robot, the robot start
Operating from the point to the end point, the speed during the operation
Command data, speed feedback data, load
The current value and the position data are collected to complete the operation.
After that, the collected speed command data and the speed feedback data are compared to check whether there is a speed change not present in the speed command data in the speed feedback data, and a speed change not present in the speed command data. It occurs but time the speed change when occurring in the speed feedback data is generated, and checks current indicating sharp peak in the load current value the collection does not flow, the current indicating the peak When the current indicating the peak occurs, and the collected position data.
Examines whether there is a sudden position change in data, the position change live
And storing a position of the robot at the stored time from the collected position data. This is an interference detection method for a robot.

[0013]

According to the robot interference detecting method of the present invention having the above-described structure, speed command data for controlling the robot,
The speed feedback data, the current value and the position data are compared and inspected, the time at which the abnormality occurs is stored, and the position at the time of the abnormality occurrence is detected from the position data. Also, when an abnormality is partially detected, the position at that time can be accurately obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the present invention is applied will be described below with reference to the accompanying drawings. Parts having the same function are denoted by the same reference numerals, and description thereof is omitted.

FIG. 1 is a block diagram of a robot control device for carrying out the present invention. This robot control device is roughly composed of a controller 10 for controlling the robot body 30, a servo amplifier unit 20 for controlling the current supplied to the robot body 30, and an interference detection computer 1 for detecting interference. And the operation of the robot itself is
The control unit 11 instructs the position control CPU 13 as a position control unit from the position data and parameters in the teach data memory 12, and the position control CPU 13 receives the operation target value. The difference between the target value and the current position data of the robot from the sensor CPU 14 as the operation speed calculation means per unit time is calculated, speed command data is created, and the speed command data is sent to the speed control CPU. The speed control CPU 21 having received the speed command data calculates the difference between the speed command data and the speed feedback data from the sensor CPU 14, creates current command data, limits the current command data to a current, and issues a command to the current control unit 22. I do. The current control unit 22, which is a current control unit that receives the current command, compares the current command data with the current detection signal from the robot body 30, and supplies the difference as a current value to the PWM drive circuit 33 of the robot. The sensor CPU 14 generates the current position data of the operating robot and the speed feedback data that is the actual operating speed by differentiating the current position data from the position detection signal from the robot.

In order to detect the value of the current flowing through the motor during operation, a resistor is connected in series to both ends of the power source of the motor, and the voltage at both ends is detected to detect the voltage value. Is detected by a current detecting unit 31 which is a current detecting unit, and a current detecting unit 31 is provided with a position detecting unit for detecting a position during operation of each axis of the robot. A certain resolver (absolute sensor) 32 is provided.

In this robot controller for carrying out the present invention, the speed command data output by the position control CPU 11 and the sensor CPU 14 output via the communication interface (I / F) 15 in the controller. The speed feedback data, the current position data, and the current detection signal (current value) from the robot are supplied to the computer 1 for interference detection.

The interference detection computer 1 compares the speed command data, the speed feedback data, the current position data, and the current detection signal with each other, and detects an interference position and performs processing for storing and storing each data. ,
A RAM 3 for temporarily storing data and a program for detecting interference, a ROM 4 for storing a basic operation of the computer for interference as a computer, a communication I / F 5 for transmitting and receiving data to and from the outside, and connecting these to each other And an external storage device 7, such as a hard disk or a magnetic tape, which stores necessary data and programs. In addition,
The interference detection computer 1 is provided with an output device (not shown) such as a display or a printer, and outputs a processing status, an interference detection result, and the like to an operator.

The computer 1 for interference detection which has received speed command data, speed feedback data, current position data and current detection signal from the controller 10 transmits each data received via the internal bus 6 to the RAM 3 or the external storage device 7 as necessary. The presence or absence of interference between the robot and the surrounding structures and the interference position when there is interference are detected from these data.

The data and the process for detecting the interference position will be described below.

FIGS. 2A to 2D are drawings for explaining each data, and the abscissa represents the time lapse in each of FIGS. 2A to 2D.

First, FIG. 2A shows speed command data, and the vertical axis indicates speed. In order to operate the robot from a certain initial position (start point) to an operation end position (end point), the speed command data is increased gradually (accelerated) first, and then operates at a constant speed when it reaches a certain speed. The speed is instructed over time so that deceleration is performed to stop the operation near the end point.

Next, FIG. 2B shows speed feedback data, in which the vertical axis represents speed. The speed feedback data is the speed of the robot actually operating, and the sensor C
The PU 14 differentiates and generates a position detection signal (current position) from the robot. As shown in the drawing, the PU 14 accelerates at first, operates at a constant speed when a certain speed is reached, and decelerates near the end point. I have.

Next, FIG. 2C shows the current detection signal, and the vertical axis indicates the current value. The current detection signal is a current value that is actually flowing to the motor of the operating robot, and when the speed is accelerating, most of the current is flowing, and when the speed is constant, the speed is maintained. Necessary current flows, and a reverse current flows in a portion where the motor decelerates.

Next, FIG. 2d shows the current position data,
The vertical axis is the distance from the origin. The current position data is a position that changes with the passage of time of the robot that is actually operating. The distance increases from the start point to the end point, and stops at the same point after reaching the end point. Here, the origin is an origin on coordinates arbitrarily set in the space where the robot is installed, and in the case shown in the figure, the starting point coincides with the origin.

Each data described above is stored in the RAM 3 by the CPU 2 of the computer 1 for interference detection, plotted as two-dimensional coordinates (three-dimensional coordinates as necessary) as shown in FIG. To detect the interference position. Each data shown in FIG. 2 is obtained when no interference occurs during the operation of the robot.

FIG. 3 shows data obtained when the robot causes interference, and the interference detection method will be described with reference to FIG. The vertical and horizontal axes are the same as those in FIG.

First, FIG. 3A shows velocity command data, which is instruction data for operating the robot. Therefore, when performing the same operation regardless of the presence or absence of interference, the same as FIG. In order to operate the robot to the end point, it is instructed to accelerate first, operate at a constant speed when the speed reaches a certain speed, and decelerate near the end point.

Next, FIG. 3B shows the speed feedback data, which is the speed of the robot actually operating. The speed is accelerated at first, operates at a constant speed when a certain speed is reached, and decelerates near the end point. If there is no interference or the like, the waveform changes with substantially the same waveform as the speed command data as shown in FIG. 2B. However, as shown in FIG. Fordback is late. That is, the portion indicated by arrow A indicates that the acceleration was hindered and the speed decreased, and there is a possibility that interference occurred at this portion.

FIG. 3C shows a current detection signal. When the speed is accelerating, a large amount of current is flowing.
In the constant speed state, a current necessary to maintain the speed flows, and in a portion where the speed is reduced, a reverse current flows. Then, a peak current larger than a normal current fluctuation flows at a portion indicated by arrow A in a portion flowing for acceleration. The fact that a lot of current is flowing means that the speed should increase (accelerate) in this part if there is no interference, etc.
In FIG. 3B, acceleration is not performed at the arrow A portion. this is,
This indicates that more current was flowing due to a larger load applied to this part than to obtain normal acceleration,
This portion has an interference Load due size kuna <br/> by the resistance, there is a possibility that excessive current flows.

Next, FIG. 3D shows the current position data. Since the increase in the distance from the origin suddenly changes at the portion indicated by the arrow A and then increases again, the interference at the changing position is large. You can see that

FIG. 4 shows the interference position detection described above.
The flow of the interference position detection will be described with reference to the flowchart shown in FIG.

First, the computer 1 for interference detection collects speed command data, speed feedback data, current position data and current detection signal from the controller 10 as time passes, and stores each data in the RAM 2 or the external storage device 7 (S1). ).

After the operation with the robot is completed from the start point to the end point, each data is plotted on two-dimensional coordinates with the horizontal axis being the same time axis (S2). Note that the vertical axis is the vertical axis of each data of FIGS. 2 and 3 described above.

Next, the CPU 2 detects an interference position. First, the interference flag is cleared to 0 as an initial setting (S2). This interference flag indicates the presence or absence of interference. 0 indicates that there is no interference, and the other numbers indicate that there is interference.

Next, the speed command data is compared with the speed feedback data to check whether or not there is a large difference between the speed command data and the speed feedback data (S4). (S5), the interference flag is set to 1 and the time on the time axis at which there is a large difference is stored (S6).

Next, the current detection signal is inspected to determine whether the current value changes rapidly and there is a peak current (S7),
If a rapid change is detected (S8),
The interference flag is set to 2 and the time on the time axis at which the change occurs is stored (S9).

Next, the current position data is inspected, and it is checked whether or not the current position is suddenly changed in a portion where the current position is moving (S10). (S11), the interference flag is set to 3, and the time on the time axis at which the change occurs is stored (S1).
2).

Next, it is checked whether or not the interference flag is 0 (S
13) If the interference flag is 0, output that there is no interference is output (S16), and the process ends. If the interference flag is not 0, the position at the time stored for each interference flag is determined. The current position data is set on the time axis, and the distance (vertical axis) from the origin at that time is detected as the position where the interference occurred (S
14) Output the position where the interference occurred (S15) and end.

In the above-described detection of the interference position, each data is sequentially compared or inspected to detect the interference position (S4 to S12), but the comparison or inspection may be performed in parallel. Also, S4 to S6, S7 to S9, S10
The comparison and inspection steps of the data of steps S12 to S12 may be performed in an order other than that shown in the drawing.

As described above, since interference is detected by comparing and checking each of the speed command data, speed feedback data, current detection signal and current position data, for example, the interference is not so large. However, even if it does not appear as a change in all data, any of the data will show a change indicating that there was interference, so even if it is a small interference, do not overlook its position Can be detected.

The robot control device used in the present embodiment is roughly divided into three units, namely, a controller 10, a servo amplifier unit 20, and a computer 1 for detecting interference, provided that the operation of each unit can be ensured. In particular, it is not necessary to form the system in such a roughly divided form, and the system may be integrally configured as a whole, or even if a computer for interference detection is arranged in the controller 10. Good. Although the supply of each data to the computer for interference detection is once performed via the communication I / F in the controller 10, each data may be directly collected by the computer 1 for interference detection. The value and the current position data may be directly received from the robot body.

[0043]

As described above, the robot interference detection method of the present invention operates the robot from the start point to the end point.
Collect the robot control data at the time of
By comparison inspection of these data, the robot and because the presence and interference positions of interference and its peripheral structure can be accurately <br/> acquisition, it is possible to perform interference prevention immediately Become. Further, as a measure for preventing interference, interference can be prevented without causing the robot to perform unnecessary operations when changing the operation path of the robot.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a robot control device according to an embodiment of the present invention.

FIG. 2 is a drawing for explaining robot control data.

FIG. 3 is a drawing for explaining robot control data when there is interference with the robot.

FIG. 4 is a flowchart for explaining an operation of interference detection using the robot control of the embodiment.

FIG. 5 is a block diagram for explaining a conventional robot control device.

[Explanation of symbols]

1. Computer for interference detection 2. CP
U, 3 ... RAM, 4 ... R
OM, 10 ... controller, 20
... Servo amplifier unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G05B 19/19 B25J 13/08

Claims (1)

(57) [Claims] An operation target value is instructed from teach data stored in advance, and a difference between the operation target value and position data from position detection means provided in a robot for detecting an operation position of each axis of the robot is obtained. Position control means for creating speed command data; operating speed calculating means for differentiating the position data to calculate speed feedback data for each axis of the robot; and taking a difference between the speed command data and the speed feedback data to obtain a current. Speed control means for creating command data, and taking the difference between the current command data and the load current value detected by the current detection means provided in the robot for detecting the current flowing in the motor driving each axis of the robot, Current control means for outputting a current to be supplied to the motors for driving the respective axes of the robot; An interference detection method for a robot operated by a bot controller, wherein the robot is operated from a start point to an end point, and
The speed command data at the speed feedback
Collect data, the load current value, and the position data
Then, after the operation is completed, the collected speed command data and the speed feedback data are compared, and it is checked whether there is a speed change not present in the speed command data in the speed feedback data. speed change that does not exist in the data to check whether no time the speed change when that occurs occurs, a current indicating sharp peak in the load current value the collected flows in the speed feedback data, the A peak current occurs
Time current indicating the peak when it has occurred, and checks whether there is a sudden change in position on the collected position data, the time when the position change when the position change has occurred is generated Storing at least one of the times, and obtaining the position of the robot at the stored time from the collected position data.