JP2020104178A - Robot device, control method of robot device, manufacturing method for article using robot device, control program and recording medium - Google Patents

Abstract

To provide a robot device that can keep holding a work-piece even if the work-piece is about to fall down from a robot hand instantly by inertia generated by quick motion of a robot arm.SOLUTION: In the robot device, a robot arm is provided with an end effector, and the end effector is provided with an end effector control device and a memorizing part that memorizes a state of the end effector. The end effector control device, when receiving a prescribed signal, controls the end effector on the basis of the state of the end effector at timing at which the prescribed signal is received, memorized in the memorizing part.SELECTED DRAWING: Figure 5

Description

The present invention relates to a robot device.

At present, in many industries, a robot apparatus such as an articulated robot arm is widely used in a factory or the like for labor saving and automation of a production site. Particularly in recent years, automation of production has accelerated due to the declining birthrate and soaring labor costs, and the demand for robot devices at production sites is increasing more and more.

A robot apparatus at a production site is mainly composed of a robot arm and a robot hand, and a product is manufactured by gripping a part by the robot hand and assembling the part gripped by the robot arm into another part.

At this time, the robot device is required to reliably grip the parts so that the parts gripped by the robot hand do not slip off the robot hand and are not damaged.

The robot hand described in Patent Document 1 is provided with a sensor for detecting the slip of an object to be grasped at the tip of the finger of the robot hand, and when the slip of the object to be grasped is detected, the grip force of the finger is increased by a predetermined amount. .. As a result, the gripping target can be reliably gripped with a minimum gripping force so that the gripping target does not slip off.

JP-A-4-189484

However, in the technique described in Patent Document 1, the relative position between the workpiece to be grasped and the robot hand is displaced, and the workpiece gradually slips off due to the workpiece being gripped in an unstable state. This is dealt with by increasing the gripping force.

Therefore, for example, when the robot arm suddenly stops due to various factors and the work suddenly drops due to inertia caused by the sudden stop, the gripping force may not be increased in time and cannot be dealt with.

Further, while the work is being gripped by the robot hand, a sudden motion of the robot arm causes an unexpected inertia to the robot hand, which causes the robot hand to come into strong contact with the work, resulting in damage to the work. there is a possibility.

Similarly, when a tool such as a screw tightening screwdriver or a polishing tool is brought into contact with the work instead of the robot hand and the robot arm suddenly stops, the above-mentioned problems occur.

In view of the above problems, in the present invention, even if the operation of the end effector such as the robot hand becomes unstable due to a sudden stop or abrupt movement of the robot arm, the end effector can be appropriately controlled according to the situation. An object of the present invention is to provide a robot device that can be used.

In view of the above problems, the present invention is a robot apparatus having a robot arm provided with an end effector, wherein the end effector is provided with an end effector control device and a storage unit that stores a state of the end effector. The end effector control device, when receiving the predetermined signal, controls the end effector based on the state of the end effector before receiving the predetermined signal stored in the storage unit. A characteristic robot device was adopted.

According to the present invention, even when the robot arm suddenly stops due to various causes, the end effector can be appropriately controlled according to the situation where the sudden stop occurs.

It is a figure which shows schematic structure of the robot apparatus 100 in 1st Embodiment. It is a figure which shows schematic structure of the robot hand main body 300 in 1st Embodiment. It is a block diagram showing a configuration of a robot apparatus 100 in the first embodiment. FIG. 3 is a control block diagram of the robot arm body 200 according to the first embodiment. 3 is a control flowchart in the first embodiment. It is a figure which shows schematic structure of the robot hand main body 300 in 2nd Embodiment. It is a figure which shows schematic structure of the robot hand main body 300 in 3rd Embodiment.

Embodiments for carrying out the present invention will be described below with reference to the embodiments shown in the accompanying drawings. Note that the embodiments described below are merely examples, and for example, the detailed configuration can be appropriately changed by those skilled in the art without departing from the spirit of the present invention. The numerical values taken in this embodiment are reference numerical values and do not limit the present invention.

(First embodiment)
FIG. 1 is a plan view of a robot apparatus 100 according to the present embodiment as seen from an arbitrary direction of an XYZ coordinate system. In the following drawings, arrows X, Y and Z in the drawings indicate the coordinate system of the entire robot apparatus 100. Generally, in a robot system using a robot apparatus, the XYZ three-dimensional coordinate system may use a local coordinate system for the robot hand, finger, etc. as appropriate in addition to the global coordinate system of the entire installation environment due to control reasons. .. In this embodiment, the coordinate system of the entire robot apparatus 100 is represented by XYZ, and the local coordinate system is represented by xyz.

As shown in FIG. 1, the robot apparatus 100 includes a multi-joint robot arm main body 200, a robot hand main body 300, and a robot arm control device 400 that controls the operation of the robot arm main body 200.

Further, an external input device 500 is provided as a teaching device that transmits teaching data to the robot arm control device 400. A teaching pendant is given as an example of the external input device 500, and is used by an operator to specify the position of the robot arm body 200 or the robot hand body 300.

In this embodiment, the case where the end effector provided at the tip of the robot arm main body 200 is a robot hand will be described, but the end effector is not limited to this and may be a tool or the like.

The link 201, which is the base end of the robot arm body 200, is provided on the base 210.

The robot hand main body 300 holds an object such as a part or a tool. The robot hand main body 300 of the present embodiment opens and closes the two fingers 301 by a drive mechanism (not shown) to grip or release the object. It suffices if the object can be gripped so as not to be displaced relative to the robot arm body 200.

The robot hand body 300 is connected to the link 206, and when the link 206 rotates, the robot hand body 300 can also rotate.

The robot arm main body 200 has a plurality of joints, for example, 6 joints (6 axes). The robot arm main body 200 has a plurality of (six) servomotors 211 to 216 that rotate and drive the joints J1 to J6 in the directions of the arrows around the respective rotation axes.

In the robot arm main body 200, a plurality of links 201 to 206 are rotatably connected at the joints J1 to J6. Here, the links 201 to 206 are sequentially connected in series from the base end side to the tip end side of the robot arm main body 200.

The robot arm main body 200 can direct the end effector (robot hand main body 300) of the robot arm main body 200 to any posture in any three directions at any three-dimensional position within the movable range.

Here, the hand of the robot arm body 200 is the robot hand body 300 in the present embodiment. When the robot hand main body 300 holds an object, the robot hand main body 300 and the held object (for example, parts or tools) are collectively referred to as the hands of the robot arm main body 200.

That is, regardless of whether the robot hand body 300 is holding an object or not, the robot hand body 300, which is an end effector, is called a fingertip.

The joints J1 to J6 have motors 211 to 216, respectively, and sensor units 221 to 226 connected to the motors 211 to 216, respectively. Each of the sensor units 221 to 226 has a position sensor (angle sensor) that detects the position of the rotating shaft of each motor and a torque sensor that detects the torque generated at each joint J1 to J6.

Further, each of the joints J1 to J6 has a speed reducer (not shown), and is connected to links 201 to 206 driven by each joint directly or via a transmission member such as a belt or a bearing (not shown).

Inside the base 210, a servo control unit 230 as a drive control unit that controls driving of the motors 211 to 216 is arranged.

The servo control unit 230 outputs a current to each of the motors 211 to 216 so that the torque of each of the joints J1 to J6 follows the torque command value based on each of the input torque command values corresponding to each of the joints J1 to J6. , Control the drive of each motor 211-216.

In addition, in the present embodiment, the servo control unit 230 is described as being configured by one control device, but is configured by an assembly of a plurality of control devices respectively corresponding to the motors 211 to 216. Good.

Further, in the present embodiment, the servo control unit 230 is arranged inside the base 210, but it may be arranged inside the robot arm control device 400.

With the above configuration, the robot arm body 200 can move the robot hand body 300 to an arbitrary position to perform a desired work. The desired work is, for example, a work of assembling objects with each other to manufacture an article.

FIG. 2 is a schematic diagram showing the configuration of the robot hand body 300 according to this embodiment. The robot hand body 300 includes a plurality of finger portions for gripping an object. As an example, the case of two fingers 301 will be described here. The two fingers 301 are driven by one motor 311.

A sensor section 321 is connected to the motor 311 and is connected to the finger section 301 via a transmission member such as a belt or a bearing (not shown). Here, the sensor unit 321 is an angle sensor that detects the rotation angle of the motor 311 corresponding to the position of the finger unit 301.

Inside the robot hand body 300, an end effector control device 351 that controls the drive of the motor 311 is arranged.

The end effector control device 351 applies a current to the motor 311 so that the position of the finger 301 and the generated gripping force follow the position command value and the gripping force command value based on the input position command value corresponding to the finger unit 301. It is output and the drive of the motor 311 is controlled.

A storage unit 361 for storing the state of the end effector is provided inside the robot hand body 300. The state of the end effector here refers to the following five states.

First, there is a state in which the robot hand body 300 is moving while the robot hand body 300 is holding the object (moving state with the object).

Secondly, there is a state in which the robot hand body 300 is moving while the robot hand body 300 is not gripping the object (moving state without the object).

Thirdly, there is a state in which the robot hand body 300 is holding an object and the robot hand body 300 is not moving (a standby state with an object).

Fourth, there is a state in which the robot hand body 300 is not gripping an object and the robot hand body 300 is not moving (a standby state without an object).

Fifth, there is a state in which the robot hand main body 300 is not moving, but the finger 301 of the robot hand main body 300 grips the target object, and thus is approaching the target object (work acquisition state).

In addition, the end effector control device 351 is provided with a control device switching unit 371. When the control device switching unit 371 receives a predetermined signal from the outside, the robot arm control device 400 controls the control device that outputs and controls the command value of the position and the gripping force of the finger portion 301 provided on the robot hand main body 300. To the end effector control device 351.

By connecting the robot hand main body 300 to the link 206, the robot hand main body 300 is connected to a communication cable (not shown) wired through the inside of the robot arm main body 200, and communication with the robot arm control device 400 is possible. ..

Further, in the present embodiment, the example in which the storage unit 361 is provided separately from the end effector control device 351 has been shown, but the storage unit 361 may be provided inside the end effector control device 351.

FIG. 3 is a block diagram showing the configuration of the robot apparatus 100 according to this embodiment. The robot arm control device 400 is configured by a computer, and the control device 400 is configured by a computer and includes a CPU (Central Processing Unit) 401 as a control unit (processing unit).

The control device 400 also includes a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, and an HDD (Hard Disk Drive) 404 as storage units. The control device 400 also includes a recording disk drive 405 and various interfaces 406 to 409.

A ROM 402, a RAM 403, an HDD 404, a recording disk drive 405, and various interfaces 406 to 409 are connected to the CPU 401 via a bus 410.

A program 430 for causing the CPU 401 to execute arithmetic processing is stored in the ROM 402. The CPU 401 executes each step of the robot control method based on the program 430 recorded (stored) in the ROM 402.

The RAM 403 is a storage device that temporarily stores various data such as the calculation processing result of the CPU 401.

The HDD 404 is a storage device that stores the calculation processing result of the CPU 401, various data acquired from the outside, and the like.

The recording disk drive 405 can read various data, programs, etc. recorded on the recording disk 431.

The external input device 500 is connected to the interface 406. The CPU 401 receives input of teaching data from the external input device 500 via the interface 406 and the bus 410.

The servo control unit 230 is connected to the interface 409. The CPU 401 acquires the detection result from each of the sensor units 221 to 226 via the servo control unit 230, the interface 409 and the bus 410. Further, the CPU 401 outputs the torque command value data of each joint to the servo control unit 230 via the bus 410 and the interface 409 at predetermined time intervals.

Similarly, the end effector control device 351 is also connected to the interface 411 and is provided so as to be communicable with the CPU 401 via the bus 410. The CPU 401 acquires the detection result from the sensor unit 321 via the end effector control device 351, the bus 410, and the interface 411. Further, the CPU 401 outputs the data of the command value of each finger 301 to the end effector control device 351 via the bus 410 and the interface 411 at predetermined time intervals.

A monitor 421 is connected to the interface 407, and various images are displayed on the monitor 421 under the control of the CPU 401. The interface 408 is configured to be connectable to an external storage device 422, which is a storage unit such as a rewritable nonvolatile memory or an external HDD.

In this embodiment, the computer-readable recording medium is the HDD 404 and the program 430 is stored in the HDD 404, but the present invention is not limited to this. The program 430 may be recorded in any recording medium as long as it is a computer-readable recording medium.

For example, as the recording medium for supplying the program 430, the ROM 402, the recording disk 431, the external storage device 422 or the like may be used. As a specific example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory, a ROM, or the like can be used as the recording medium.

FIG. 4 is a control block diagram showing a control system of the robot arm main body 200 of the robot apparatus 1000 according to this embodiment. The CPU 401 (FIG. 3) of the control device 400 functions as the force control unit 504 and the position target value generation unit 505 by executing the program 430 (FIG. 3).

The servo control unit 230 functions as a plurality (six since it has six joints) of switching control units 511 to 516, a plurality of position control units 521 to 526, and a plurality of motor control units 531 to 536.

Each of the sensor units 221 to 226 has position sensors (angle sensors) 551 to 556 and torque sensors 541 to 546 (torque detecting means). The position sensors 551 to 556 detect the angles (positions) of the motors 211 to 216 or the joints J _{1 to} J ₆ , respectively.

In the present embodiment, the position sensors 551 to 556 directly detect the angles θ _{1 to} θ ₆ of the motors 211 to 216. The angle _q 1 to q ₆ joints _J 1 through J ₆ on the basis of the reduction ratio or the like of the reduction gear, not shown, can be determined from the angle theta ₁ through? ₆ which are detected by the position sensor 551 to 556. Accordingly, the position sensor 551 to 556 would indirectly has detected an angle _q 1 to q ₆ of each joint _J 1 through J _6. The torque sensors 541 to 546 detect the torques τ _{1 to} τ ₆ of the joints J _{1 to} J ₆ , respectively.

The external input device 500 outputs the force target value F _d included in the force teaching data 501 and the position target value P _d included in the position teaching data 502 to the CPU 301 according to the operation of the operator. The force target value F _d is a target value of the force generated by the hand of the robot arm body 200, and is set by the operator using the external input device 500.

The position target value P _d is a target value of the position of the hand of the robot arm main body 200, and is set by the operator using the external input device 500. A robot model 503 is stored in the external storage device 422.

The force control unit 504 inputs the robot model 503 including the hand load model, the force target value F _d , the position target value P _d , the current position P, and the force F. Then, the force control unit 504 uses these values to determine the torque command value τ _Fd1 ~τ _Fd6 for each joint _J 1 through J _6.

At this time, the torque command values τ _{Fd1 to} τ _Fd6 are _calculated so that the force deviation between the hand force F and the force target value F _d and the position deviation between the hand position P and the position target value P _d become small. The force control unit 504 outputs the obtained torque command values τ _{Fd1 to} τ _Fd6 to the switching control units 511 to 516, respectively.

The position target value generation unit 505 obtains angle command values (position command values) q _{d1 to} q _d6 of the joints J _{1 to} J ₆ from the target position value P _d of the hand by inverse kinematics calculation, and each angle command value q. the _d1 to q _d6 outputs to the position control unit 521 to 526.

Each position control unit 521 to 526, the torque command so that the angular deviation between the angle _q 1 to q ₆ of each joint _J 1 through J ₆ and angle command value _q d1 _{to q d6} of the joints _J 1 through J ₆ is reduced Values τ _{Pd1 to} τ _Pd6 are _obtained . It should be noted that reducing the angle deviation is equivalent to reducing the angle deviation between the angle of each of the motors 211 to 216 and the angle command value obtained by converting the angle command values q _{d1 to} q _d6 by the reduction ratio of the speed reducer or the like. Is. The position control units 521 to 526 output the torque command values τ _{Pd1 to} τ _Pd6 to the switching control units 511 to 516, respectively.

Each of the switching control units 511 to 516 controls switching between a force control mode for performing torque-based force control and a position control mode for performing position control. Each switch control unit 511 to 516, the force control mode is output to each motor control unit 531 to 536 each torque command value τ _Fd1 ~τ _Fd6 as the torque command value _{τ d1 ~τ d6.} Each switch control unit 511 to 516, the position control mode is output to each motor control unit 531 to 536 each torque command value τ _Pd1 ~τ _Pd6 as the torque command value _{τ d1 ~τ d6.}

Each of the motor control units 531 to 536 sets each of the currents Cur _{1 to} Cur ₆ so as to realize each of the torque command values τ _{d1 to} τ _d6 based on the angles (positions) θ _{1 to} θ ₆ of the motors 211 to 216. The motors 211 to 216 are energized.

With the above configuration, the robot arm main body 200 can be made to execute position control controlled by position information and force control controlled by force information such as torque.

FIG. 5 is a flowchart showing the control method in this embodiment. The CPU 401 of the robot arm control device 400 executes the program 430 to operate the robot arm main body 200.

From FIG. 5, first, the robot apparatus 100 starts operation. Then, in S101, the state of the robot hand body 300 is stored in the storage unit 361 inside the robot hand body 300.

The states of the robot hand main body 300 mentioned here are the above-mentioned five states of the moving state with the work, the moving state without the work, the waiting state with the work, the waiting state without the work, and the work acquiring state. These states are determined based on the detection result from the sensor unit 321 provided in the robot hand body 300, and are stored in the storage unit 361.

Next, in S102, the controller switching unit 371 inside the robot hand main body 300 determines whether or not a predetermined controller switching signal is received from the outside. The control device switching signal is a signal indicating that the robot arm main body 200 has performed a steep motion due to a sudden stop or the like.

This time, the robot arm control device 400 calculates the acceleration applied to the robot hand main body 300 based on the detection results of the sensor units 221 to 226 provided on the robot arm main body 200. When the acceleration applied to the robot hand body 300 exceeds a predetermined value, the robot arm control device 400 determines that the robot arm body 200 has performed a steep motion. Then, a control device switching signal is transmitted from the robot arm control device 400 to the control device switching unit 371.

If the acceleration applied to the robot hand main body 300 does not exceed a predetermined value, it is determined that the robot arm main body 200 is not performing a steep motion, and the control device switching signal is not transmitted to the control device switching unit 371.

When the control switching signal is not transmitted to the control device switching unit 371, S102: NO, the process returns to immediately before S101 and the state of the robot hand main body 300 is stored in the storage unit 361 again. As a result, the state of the robot hand body 300 before the control device switching signal is transmitted to the control device switching unit 371 can always be stored.

When the acceleration applied to the robot hand body 300 exceeds a predetermined value, it is determined that the robot arm body 200 is performing a steep motion, and the control device switching signal is transmitted to the control device switching unit 371.

In the present embodiment, the acceleration sensor is calculated by the torque sensor, but the acceleration sensor for detecting the acceleration is provided in the robot hand main body 300 and the value of the acceleration is directly detected to transmit the control device switching signal. Good as a trigger.

Further, not only the torque sensor but also a force sensor, a position sensor or the like may be used to appropriately use a detection unit capable of detecting a physical quantity for calculating the acceleration to calculate the acceleration.

When the control device switching signal is transmitted to the control device switching unit 371, S102: YES, and the process proceeds to S103.

In S103, the control device for controlling the robot hand body 300 is changed from the robot arm control device 400 to the end effector control device 351. Hereinafter, the control flow from S104 is performed by the end effector control device 351.

In S104, it is determined by referring to the storage unit 361 whether the state of the robot hand body 300 before the control device switching signal is transmitted to the control device switching unit 371 is the “moving state with object”. If it is not in the "moving state with target object", S104 is NO and the process proceeds to S105. If it is in "moving state with target object", the process proceeds from S104: YES to S109.

In S109, the gripping force of the finger portion 301 is increased by a predetermined amount (+ΔT[N]) so that the object gripped by the robot hand body 300 does not drop due to the abrupt movement of the robot arm body 200. Accordingly, even if the robot hand body 300 is accelerated and inertia is applied to the gripped target object, the gripped target object can be prevented from falling.

At this time, the operator may be allowed to appropriately set the amount of change ΔT in gripping force. By doing so, if the amount of change is such that the work is not damaged due to an increase in gripping force, the risk of object damage can be further reduced.

In S105, it is determined by referring to the storage unit 361 whether the state of the robot hand main body 300 before the control device switching signal is transmitted to the control device switching unit 371 is the “object-less moving state”. If it is not the "moving state without the object", S105: NO and the process proceeds to S106. If it is the "moving state without the object", S105: YES and the process proceeds to S110.

Here, in the “moving state without an object”, since the robot hand main body 300 does not hold the object, there is no risk of dropping the work. Therefore, since the end effector control device 351 does not perform the control operation of protecting the object, the gripping force performed in S109 is not increased.

In S110, the position of the finger 301 is moved to the position of the finger 301 before the control device switching signal stored in the storage unit 361 is transmitted to the control device switching unit 371. As a result, the state of the robot hand main body 300 before the control device switching signal is transmitted to the control device switching unit 371 is maintained.

In S106, it is determined whether the state of the robot hand main body 300 before the control device switching signal is transmitted to the control device switching unit 371 is the “object waiting state” by referring to the storage unit 361. If the "object waiting state is not present", the process proceeds from S106: NO to S107, and if the "object present standby state" is performed, proceeds from S106: YES to S109.

In the "standby state with an object", acceleration means that the robot arm control device 400 has an abnormality, the robot arm body 200 suddenly stops, and the position of the robot hand body 300 cannot be maintained. , It seems that the position changed suddenly.

Therefore, in S109, the gripping force of the finger portion 301 is increased by a predetermined amount (+ΔT[N]) so that the object gripped by the robot hand body 300 does not drop due to the sudden stop of the robot arm body 200. Accordingly, even if the robot hand body 300 is accelerated and inertia is applied to the gripped target object, the gripped target object can be prevented from falling.

In S107, it is determined whether or not the state of the robot hand main body 300 before the control device switching signal is transmitted to the control device switching unit 371 is the “object-less standby state” by referring to the storage unit 361. If it is not in the "object-less standby state", the process proceeds from S107: NO to S108, and if it is in the "object-less standby state", proceeds from S107: YES to S110.

Here, in the “object-less standby state”, since the robot hand main body 300 does not grip the object, there is no risk of dropping the work. Therefore, since the end effector control device 351 does not perform the control operation of protecting the object, the gripping force performed in S109 is not increased.

In S110, the position of the finger 301 is moved to the position of the finger 301 before the control device switching signal stored in the storage unit 361 is transmitted to the control device switching unit 371. As a result, the state of the robot hand main body 300 before the control device switching signal is transmitted to the control device switching unit 371 is maintained.

Proceeding to S108 means that only the remaining “object approaching state” remains among the five states, and therefore the state of the robot hand body 300 before the control device switching signal is transmitted to the control device switching unit 371. Is in the “approaching state of the object”.

Then, in S108, the position of the finger portion 301 of the robot hand body 300 is moved so as to open it to a position where it does not contact the object. Specifically, the position of the finger 301 is moved to the most open position.

Here, in the “approaching state of the object”, the finger 301 is made to approach the object at a constant speed until it comes into contact with the object while controlling the gripping force of the finger 301 to grip the object. The speed is controlled.

Therefore, by moving the finger portion 301 to the most open position, the finger portion 301 can be separated from the target object, and the steep motion of the robot arm main body 200 may cause the finger portion 301 to contact and damage the target object. Can be reduced.

Hereinafter, the effect of each state of the robot hand main body 300 will be described with a specific example.

First, when the robot hand main body 300 is in the “moving state with target object” or “standby state with target object”, the finger portion 301 of the robot hand main body 300 is controlled so as to generate a certain gripping force in a certain direction of the target object. Has been done. Therefore, the risk of the object falling can be reduced.

Next, when the robot hand body 300 is in the “moving state without object” or “standby state without object”, the robot 301 before the control device switching signal is transmitted to the control device switching unit 371 by the finger 301 of the robot hand body 300. The state of the hand body 300 is maintained. By doing so, the standby state can be maintained.

As described above, according to the present embodiment, the control of the robot hand body 300 is switched to the end effector control device 351 when the robot arm body 200 undergoes a steep motion.

As a result, the control device located near the robot hand body 300 can be used to perform control to prevent the object from falling, so that the responsiveness of the control can be improved and the object can be dropped instantly. Even if it happens, the fall prevention control can be made in time.

In addition, the state of the robot hand body 300 is stored, and the content of the fall prevention control is changed according to various states of the robot hand body 300.

As a result, flexible fall prevention control can be performed, and there is also a risk of damage to the object due to factors other than the drop, such as damage to the object due to increased gripping force, damage due to strong contact between the finger and the object. It can be reduced.

It should be noted that although the present embodiment has been mainly described by taking five states as an example, the present invention is not limited to this. For example, when the end effector is not a robot hand but a tool such as a polishing tool or a driver, the method for determining the state may be changed and the control content may be changed depending on the tool.

(Second embodiment)
In the first embodiment, the signal for switching the control device is triggered by the acceleration applied to the robot hand main body 300. However, for example, when some abnormality occurs in the robot arm control device 400 that controls the robot arm body 200, the robot arm body 200 may be emergency stopped.

At this time, the robot arm body 200 suddenly stops, so that unexpected acceleration is applied to the robot hand body 300.

However, in the first embodiment, the robot arm controller 400 calculates the acceleration applied to the robot hand body 300 based on the detection results of the sensor units 221 to 226.

Therefore, when the robot arm control device 400 has an abnormality, the acceleration cannot be calculated and the object fall prevention control cannot be executed.

In the present embodiment, a control method that can reduce the risk of falling of an object even when the robot arm control device 400 has an abnormality as described above will be described.

In the following, hardware and control system components different from those of the first embodiment will be illustrated and described as necessary. Further, regarding the same parts as those of the first embodiment, the same configurations and operations as those described above are possible, and detailed description thereof will be omitted.

FIG. 6 is a schematic diagram of the robot hand body 300 according to this embodiment. In the present embodiment, the robot hand main body 300 is provided with an abnormality detection unit 381 that detects that an abnormality has occurred in the robot arm control device 400.

The abnormality detecting unit 381 detects that the communication signal from the robot arm control device 400 is cut off, as a method of detecting an abnormality.

When no abnormality has occurred, the robot arm control device 400 outputs control values for controlling the finger portion 301 to the robot hand body 300 at predetermined time intervals ΔT ₁ .

For this ΔT _1, ΔT _2> ΔT ₁ become such [Delta] T ₂ are set in advance, when the control value even after time [Delta] T ₂ is not output from the robot arm controller 400, The abnormality detection unit 381 determines that an abnormality has occurred in the robot arm control device 400.

Then, the abnormality detection unit 381 transmits the control device switching signal to the control device switching unit 371 in S102 of FIG.

After that, the same control as the flow of FIG. 5 is performed by the end effector control device 351.

As described above, even if some abnormality occurs in the robot arm control device 400, the robot arm main body 200 is brought to an emergency stop, and unexpected acceleration is applied to the robot hand main body 300, the object fall prevention control can be performed.

As another abnormality detection method, a case of detecting that the power supply voltage from the robot arm control device 400 is cut off will be described.

May be set the threshold voltage as a [Delta] V _th, the power supply voltage V _n is supplied from the robot arm control apparatus 400, when a V n _<[Delta] V _th, the abnormality detection unit 381 control unit a control device switching signal It is transmitted to the switching unit 371.

Thereby, similarly to the above, the abnormality of the robot arm control device 400 can be detected, and even if the robot arm control device 400 has some abnormality and unexpected acceleration is applied to the robot hand main body 300, the object fall prevention control is performed. It can be performed.

In the case of the present embodiment, the control of the end effector after the robot arm control device 400 recovers from the abnormality may be set separately.

(Third Embodiment)
In the first and second embodiments described above, the communication between the end effector control device 351 and the robot arm control device 400 is performed by wire communication.

However, the electrical connection between the robot hand main body 300 and the robot arm main body 200 is made wireless, a communication cable is wired to the robot arm main body 200, and the control of the finger portion 301 is controlled by semi-wired or semi-wireless. It is effective even when using the communication of.

The half-wired or half-wired communication method described above uses a known technique described in Japanese Unexamined Patent Application Publication No. 2012-101315 or the like, and a detailed description thereof will be omitted.

The above-described semi-wired or semi-wired communication method has a problem that communication in the wireless part is unstable.

Therefore, if the communication of the wireless part is interrupted, the control of the finger portion 301 cannot be performed, and there is a risk that the held object is dropped.

In the present embodiment, as described above, there is a wireless part in the communication between the finger unit 301 and the robot arm control device 400, and even if the communication is interrupted, a control method that can reduce the risk of falling of an object will be described. To do.

In the following, hardware and control system components different from those in the first and second embodiments will be illustrated and described as necessary. Further, regarding the same parts as those of the first embodiment, the same configurations and operations as those described above are possible, and detailed description thereof will be omitted.

FIG. 7 is a schematic diagram of the link 206 between the robot hand body 300 and the robot arm body 200 in this embodiment. In this embodiment, a wireless communication unit 391 for wirelessly communicating the communication cable 240 arranged from the robot arm control device 400 and the end effector control device 351 is provided inside the robot hand main body 300.

Similarly, the wireless communication unit 391 is provided inside the link 206 and is connected to the communication cable 240. Thereby, the communication between the end effector control device 351 and the robot arm control device 400 can be performed in a semi-wired or semi-wired manner.

In the present embodiment, the power supply voltage input to the end effector 351 is assumed to be supplied by wire by a power supply cable (not shown).

Further, the wireless communication unit 391 also has a function of detecting that wireless communication is interrupted. This will be described in detail below.

When the wireless communication is not interrupted, the robot arm control device 400 outputs a control value for controlling the finger portion 301 to the robot hand body 300 at predetermined time intervals ΔT ₃ .

For this ΔT _3, ΔT _4> ΔT ₃ become such [Delta] T ₄ are set in advance, when the control value with time of [Delta] T ₄ is not output from the robot arm controller 400, The wireless communication unit 391 determines that the communication is interrupted.

Then, the wireless communication unit 391 transmits a control device switching signal to the control device switching unit 371 in S102 of FIG.

After that, the same control as the flow of FIG. 5 is performed by the end effector control device 351.

As described above, there is a wireless part in the communication between the finger unit 301 and the robot arm control device 400, and even if the communication is interrupted, the risk of dropping the object can be reduced.

In the case of the present embodiment, the control of the end effector after the wireless communication is restored may be set separately.

The processing procedures of the various embodiments described above are specifically described as being executed by the end effector control device 451. However, the control program of software capable of executing the above-described functions and the recording medium recording the program may be mounted in another device and implemented.

Therefore, the software control program capable of executing the above-described functions and the recording medium recording the program constitute the present invention.

In the above embodiment, the computer-readable recording medium is the ROM or the RAM, and the control program is stored in the ROM or the RAM. However, the present invention is not limited to such a form. Absent.

The control program for carrying out the present invention may be recorded in any recording medium as long as it is a computer-readable recording medium. For example, an HDD, an external storage device, a recording disk, or the like may be used as the recording medium for supplying the control program.

(Other embodiments)
In the above-described various embodiments, the case where the robot apparatus 100 uses the multi-joint robot arm having a plurality of joints has been described, but the number of joints is not limited to this. Although the vertical multi-axis configuration is shown as the type of the robot apparatus, the same configuration as the above can be implemented in joints of different types such as a parallel link type.

In addition, although the configuration example of the robot apparatus 100 is shown by the example diagram of each embodiment, the configuration is not limited to this and a person skilled in the art can arbitrarily change the design. In addition, each motor provided in the robot apparatus 100 is not limited to the above-described configuration, and the drive source that drives each joint may be, for example, a device such as an artificial muscle.

Further, the various embodiments described above are applied to a machine capable of automatically performing an operation of expansion/contraction, bending/extension, vertical movement, horizontal movement or turning, or a combined operation thereof based on information in a storage device provided in the control device. It is possible.

100 robot device 200 robot arm main body 210 base 201, 202, 203, 204, 205, 206 link 211, 212, 213, 214, 215, 216, 311 motor 221, 222, 223, 224, 225, 226, 321 sensor Part 240 Communication cable 300 Robot hand main body 301 Finger part 351 End effector control device 361 Storage part 371 Control device switching part 381 Abnormality detection part 391 Wireless communication part

Claims (15)

A robot apparatus having an end effector on a robot arm,
The end effector includes
An end effector control device,
A storage unit that stores the state of the end effector is provided,
The end effector control device,
A robot apparatus, which, when receiving a predetermined signal, controls the end effector based on a state of the end effector stored in the storage unit before the reception of the predetermined signal. The robot apparatus according to claim 1,
The end effector control device,
A robot apparatus, which, upon receiving the predetermined signal, controls the end effector so as to maintain the state of the end effector stored in the storage unit before the reception of the predetermined signal. The robot apparatus according to claim 1 or 2,
A robot arm control device for controlling the robot arm,
The end effector includes an abnormality detection unit that detects that an abnormality has occurred in the robot arm control device,
The robot device, wherein the predetermined signal is a signal that is transmitted from the abnormality detection unit and indicates that an abnormality has occurred in the robot arm control device. The robot apparatus according to claim 1 or 2,
The end effector includes a detection unit that detects acceleration generated in the end effector,
The robot apparatus, wherein the predetermined signal is a signal transmitted from the detection means and indicating that a predetermined acceleration value has been detected. The robot apparatus according to claim 1 or 2,
A robot arm control device for controlling the robot arm,
The end effector includes a wireless communication unit that wirelessly communicates with the robot arm control device,
The robot device, wherein the predetermined signal is a signal transmitted from the wireless communication unit and indicating that an abnormality has occurred in communication with the robot arm control device. The robot apparatus according to any one of claims 3 to 5,
The robot arm control device also controls the end effector,
The end effector control device has a switching unit,
The switching device, when receiving the predetermined signal, switches from the robot arm control device to the end effector control device and controls the end effector by the end effector control device. The robot apparatus according to claim 1,
The end effector is a robot hand, the robot hand includes at least two fingers, and the fingers can grip an object.
The end effector control device,
A robot apparatus characterized in that, when the predetermined signal is received while the finger section is approaching the object, the finger section is controlled so as to be separated from the object. The robot apparatus according to claim 7,
The end effector control device,
A robot apparatus, wherein when the predetermined signal is received while gripping the target object, the finger unit is controlled so as to increase the grip force. The robot apparatus according to claim 8,
A robot apparatus, wherein a value for increasing the gripping force can be set by an operator. An end effector,
A control device,
A storage unit that stores the state of the end effector is provided,
The control device is
An end effector, which receives the predetermined signal and controls the end effector based on a state of the end effector stored in the storage unit before the reception of the predetermined signal. The end effector according to claim 10,
The control device is
An end effector that controls the end effector so as to maintain the state of the end effector before receiving the predetermined signal from the storage unit when the predetermined signal is received. A method for controlling a robot apparatus, wherein an end effector is provided on a robot arm,
The end effector includes
An end effector control device,
A storage unit that stores the state of the end effector is provided,
The end effector control device,
A control method, comprising: receiving a predetermined signal, controlling the end effector based on a state of the end effector stored in the storage unit before the input of the predetermined signal. A method for manufacturing an article using a robot apparatus having an end effector on a robot arm, comprising:
The end effector includes
An end effector control device,
A storage unit that stores the state of the end effector is provided,
The end effector control device,
When a predetermined signal is received, the end effector is controlled based on the state of the end effector before the reception of the predetermined signal stored in the storage unit, and an article is manufactured. Production method. A control program capable of executing the control method according to claim 12 or the method for manufacturing an article according to claim 13. A computer-readable recording medium in which the control program according to claim 14 is recorded.

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