JP2019181639A - Robot hand, robot hand control method, article assembling method using robot hand, program, and recording medium - Google Patents

Abstract

To provide a robot hand capable of stably gripping a wide variety of workpieces by using a simple and inexpensive mechanism.SOLUTION: A robot hand comprising a plurality of finger parts brings the finger parts closer to an object in a state in which at least one of the finger parts can be turned, and locks a support mechanism for rotatably supporting the finger parts by a lock mechanism after the finger part brought closer to the object is brought contact with the object.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a robot hand.

  In recent years, robot hands have been used for automatic assembly of products of high-mix low-volume production. In the assembly of such a product of high-mix low-volume production, there are many cases where the work handled is various, such as a high-mix, complex shape, and flexible material. However, when there are a wide variety of workpieces, it is difficult to bring the workpieces into contact with each other at a predetermined contact position of the finger part of the robot hand depending on the shape of each workpiece. For this reason, if the contact position is misaligned and gripped, gripping becomes unstable, causing the workpiece to drop off during transfer of the workpiece, or to cause problems during assembly, leading to reduced productivity. There is a need for improved stability.

  The robot hand described in Patent Document 1 is provided with a finger mechanism including a link mechanism having two or more nodes in the robot hand, and at least one link member having a mechanism that rotates about an axis in the fingertip direction. Realizes stable gripping for a wide variety of workpieces.

JP 2006-43843 A

  However, in the robot hand described in Patent Document 1, a pressure-sensitive sensor is provided at the fingertip to confirm the gripping state of the workpiece, and a camera is used to confirm the posture of the gripped workpiece. Based on the gripping state detected by these pressure-sensitive sensors and cameras, a large-scale processing device is required to perform control for rotating the finger member, and the number of components such as cameras increases, so that the robot hand Increases size and cost.

  An object of the present invention is to provide a robot hand that can stably hold a wide variety of workpieces using a simple and inexpensive mechanism.

In order to solve the above-described problems, the present invention is a robot hand that includes a plurality of finger parts and grips an object with the finger parts, and a driving mechanism that moves the finger parts closer to or away from each other. A support mechanism for rotatably supporting at least one of the fingers, a lock mechanism for preventing rotation of at least one of the fingers, and a control for controlling the drive mechanism, the support mechanism, and the lock mechanism The control device causes the finger to approach the object in a state in which at least one of the fingers can be rotated by the drive mechanism,
A robot hand is used in which the support mechanism is locked by the lock mechanism after the finger portion approached comes into contact with the object.

  According to the present invention, a locking mechanism capable of locking the rotation of the finger portion is used for the finger portion, and the finger portion is made to follow the shape of the workpiece by contacting the workpiece and the finger portion in a state where the rotation can be freely performed. Is locked by a locking mechanism. As a result, the displacement of the contact position between the workpiece and the finger portion can be reduced with a simple and inexpensive mechanism, and a wide variety of workpieces can be stably held.

1 is a schematic diagram of a robot system 100 according to a first embodiment of the present invention. It is a detailed view of the robot hand main body 300 in the first embodiment of the present invention. It is a block diagram of robot hand control device 500 in a 1st embodiment of the present invention. It is a block diagram of finger part control board 520 in a 1st embodiment of the present invention. It is a flowchart of the holding | grip operation | movement in the 1st Embodiment of this invention. It is a flowchart which detects the completion of holding | grip in the 1st Embodiment of this invention. FIG. 7 is a state diagram in each step of the flowcharts in FIGS. 5 and 6. It is the schematic of the finger part 306a in the 2nd Embodiment of this invention. It is a flowchart which changes the contact surface in the 2nd Embodiment of this invention. It is a figure showing the modification of the finger part 306a in the 2nd Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The embodiment described below is merely an example, and for example, a detailed configuration can be appropriately changed by those skilled in the art without departing from the spirit of the present invention. Moreover, the numerical value taken up by this embodiment is a reference numerical value, Comprising: This invention is not limited.

(First embodiment)
Hereinafter, the configuration and grip control in the first embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of a robot system of the present embodiment using the robot apparatus of the present invention.

  In FIG. 1, a robot system 100 according to this embodiment includes a robot arm main body 200, a robot hand main body 300, a system control device 400 that controls the entire robot system, and an external input device 800. The workpiece W1 that is the assembly target is placed on the workpiece mounting table S1, and the workpiece W2 that is the assembly target is fixed on the workpiece fixing base S2.

  By manipulating and assembling the workpiece W1 and the workpiece W2 by the robot system 100, an article or a part thereof can be manufactured. For example, in the assembling operation for the workpieces W1 and W2, the workpiece W1 as an assembling target is gripped and moved using the robot arm main body 200 and the robot hand main body 300, and the workpiece W1 is fitted to the workpiece W2. It is done by the operation.

  The robot arm body 200 is an articulated robot arm in this embodiment, and the base of the robot arm body 200 is fixed to the base 900. At the tip of the robot arm body 200, a robot hand body 300 as a gripping device is attached. The robot hand body 300 is used to perform an operation on the workpiece W1. Each joint of the robot arm body 200 is provided with a motor as a drive source for driving each of the joints and an encoder as a position detection unit for detecting the rotation angle of the motor. In addition, the installation position and output system of an encoder are not ask | required.

  The robot hand body 300 is a hand that opens and closes a plurality of fingers by a motor and an opening / closing mechanism to grip or release the workpiece W1, and can grip the workpiece W1 without being displaced relative to the robot arm body 200. Details will be described later.

  In this embodiment, the robot hand 300 moves the finger by motor driving, but may be an air gripper such as pneumatic driving. Furthermore, the robot hand body 300 may be a suction mechanism as long as it can grip the workpiece W1 so as not to be displaced relative to the robot arm body 200.

  The system controller 400 includes a robot arm controller 600 that controls the robot arm body 200 and a robot hand controller 500 that controls the robot hand body 300. In the present embodiment, the robot arm main body 200 and the robot hand main body 300 are controlled using separate control devices, but may be integrated and controlled using a single control device.

  As shown in FIG. 1, the robot hand control device 500 and the robot arm control device 600 are composed of CPUs 501 and 601 each composed of a microprocessor or the like. Furthermore, ROMs 502 and 602, RAMs 502 and 603, and general-purpose signal interfaces 504 and 604 are connected to each CPU by buses. Then, motors (not shown) provided in the robot hand main body 300 and the robot arm main body 200 are controlled via motor drivers 505 and 605, respectively.

  The ROMs 502 and 602 store control programs for controlling the drive units corresponding to the robot hand main body 300 and the robot arm main body 200 according to various operations, data necessary for the control, and the like. The RAM 503 and 603 develop data, setting values, control programs, and the like necessary for controlling these robot systems.

  The general-purpose input / output interfaces I / O 504 and 604 are connected to an external input device 800 such as a teaching pendant. As a result, the user can directly operate the robot system 100.

  The general-purpose input / output interfaces I / O 504 and 604 are connected to the robot hand main body 300 and the robot arm main body 200 so as to be able to transmit and receive. Therefore, the robot hand control device 500 and the robot arm control device 600 can directly communicate with each other. Thus, feedback control can be performed based on the values detected by the encoders and the force sensor 700 of the robot hand body 300 and the robot arm body 200 described above.

  The workpiece W1 has an assembly portion (convex portion) to which the workpiece W2 is assembled. In this embodiment, the convex part assumes a cylindrical pin. Moreover, the workpiece | work W2 has an assembly | attachment part (concave part) for the workpiece | work W1 to assemble | attach. In the present embodiment, the recess is assumed to be a cylindrical hole.

  FIG. 2 is a perspective view of the robot hand body 300 in the present embodiment. The robot hand main body 300 includes a palm portion 301, a mounting portion 302 with the robot arm main body 200, finger portions 306, 307, 308, and a restriction portion 309 that restricts the movement of the finger portions 306, 307, 308.

  Inside the palm 301, there is provided a motor 310 serving as a drive source for driving the finger portions 306, 307, 308 in the direction of arrow A, which is a direction toward or away from the point C. The finger portions 306, 307, and 308 are installed on the guide rail 305, and are connected to the motor 310 by a transmission mechanism including a rack and pinion (not shown).

  Thus, by driving the motor 310, the finger portions 306, 307, and 308 move on the guide rail 305, and the finger portions 306, 307, and 308 open and close, thereby gripping and releasing the workpiece W1.

  The drive mechanism that combines the motor 310 and the transmission mechanism composed of the rack and pinion described above is an example of a drive mechanism that causes the fingers to approach or separate from each other. For example, a motor may be provided for each finger part, and the finger part that transmits and drives the motor by a link mechanism to perform an opening / closing operation may be used. Further, the finger portions 306, 307, and 308 may be opened and closed via a cam mechanism.

  In addition, the fingers 306, 307, and 308 lock the rotation of the motor 304 as a driving source that rotates the fingers 306, 307, and 308 in the direction of arrow B around the rotation axes O1, O2, and O3, respectively. Solenoids 303 are disposed respectively. In this embodiment, the motor 304 is used as a drive source for rotating the finger portions 306, 307, 308. However, at the same time, the motor 304 may be a support mechanism that rotatably supports the finger portions 306, 307, 307 by the rotation shaft of the motor 304. Works.

  Further, a solenoid 303 is used as a locking mechanism. By supplying a current to the solenoid 303, the fingers 306, 307, 308 can be freely rotated, and by stopping the current supply, the fingers 306, 307, 308 can be freely rotated. Can be.

  When the external force is applied to the finger portions 306, 307, and 308 while the motor 304 is not locked by the solenoid 303, the finger portions 306, 307, and 308 can be passively rotated by the drive shaft of the motor 304. It shall be.

  In this embodiment, the locking mechanism is the solenoid 303, but it may be a shoe clutch. If it is not necessary to rotate the finger portions 306, 307, and 308, a support mechanism that simply supports the finger portions 306, 307, and 308 rotatably by a mechanism such as a bearing instead of the motor 304 as the above-described support mechanism. It may be used. In this case, passive rotation of the fingers 306, 307, and 308 by a support mechanism such as a bearing is locked by a lock mechanism such as a shoe clutch.

  Next, a detailed block diagram of the robot hand control device 500 in this embodiment is shown in FIG. The position target value and the speed target value of each finger from the command value generator 506 are output to the motor 310 for approaching or separating each finger through each block. The motor 310 is provided with an encoder 311. By detecting the rotation angle of the rotation shaft of the motor 310, each finger can be placed at a predetermined position.

  The finger units 306, 307, and 308 are provided with finger unit control boards 520 for controlling the rotation. Details will be described later.

  In the figure, the position target value output from the command value generator 506 is input to the position control block 507 by calculating the deviation between the position acquired from the encoder 311 and the position target value from the command value generator. .

  The position control block 507 is a so-called PID controller (Proportional Integral Differential Controller) that determines an output value from a deviation by proportionality, integration, and differentiation. The proportional coefficient, integral coefficient, and differential coefficient used in the position control block 504 use preset coefficient values.

  The output from the position control block 507 is switched to a speed target value to be input to the speed control block 510 via the switching block 508. A switching block 508 is a switch that switches between a speed target value when executing speed control and an output value from the position control block 507.

  A speed control block 510 calculates a deviation between the speed target value, the position acquired from the encoder 311 and the previous position acquired from the encoder 311 from the speed calculated by the differential block 509 for the rotational speed of the rotating shaft of the motor 310. To enter.

  The speed control block 510 executes a PID control process similar to that of the position control block 507 at a cycle of 0.5 milliseconds to control the rotational speed of the rotating shaft of the motor 310. As the proportional coefficient, integral coefficient, and differential coefficient used in the speed control block 510, preset coefficient values are used.

  The output from the speed control block 510 is set to a current target value that becomes an input to the current control block 512 via the switching block 511. The switching block 511 is a switch that switches between a current target value when executing current control and an output value from the speed control block 510.

  The current target value and the current flowing through the motor 310 detected by the current detection unit 514 are analog / digital converted by the AD converter 513, and the deviation between the two is input to the current control block 512.

  The current control block 512 executes PID processing similar to that of the position control block 507 and the speed control block 510 and is executed at a period of 0.1 millisecond, and controls the current flowing through the motor 310.

  As the proportional coefficient, integral coefficient, and differential coefficient used in the current control block 512, preset coefficient values are used. The output value of the current control block 512 is output to the motor 310 by the inverter 515 as PWM (Pulse Width Modulation) to drive the motor.

  In addition, although control of the motor 310 in this embodiment is feedback control using PID control, you may use together the control method using feedforward control and an observer.

  FIG. 4 shows a detailed block diagram of the finger part control board 520 provided in each of the finger parts 306, 307, and 308 in the present embodiment.

  The finger control board 520 includes a power supply circuit 521 that supplies power for driving the calculator 522, the motor 304, and the solenoid 303.

  Furthermore, by communication with the command generator 506, a communication driver 523 that exchanges values from the command generator 506, a motor drive circuit 525 that drives each motor 304 responsible for rotation of each finger, and each solenoid 303 that performs rotation restraint. A solenoid drive circuit 524 for driving the motor.

  Each motor 304 is provided with an encoder 341 that detects the rotation angle of the rotation shaft of each motor 304. Thereby, the rotation angle of each finger part 306,307,308 can be detected, and it can control rotation of each finger part so that it may become a desired holding position by feeding back to the calculator 522. Each finger control board 520 is provided with a current detection unit 526 that detects a current flowing in the drive wiring of the motor 304.

  In the figure, a command generator 506 sends a position command value or a speed command value with a gripping position of each finger part 306, 307, 308 corresponding to a gripping work as an object as a target value via a communication driver 523. Transmit to the calculator 522.

  The arithmetic unit 522 outputs a control value for driving the motor 304 and the solenoid 303 to the motor driving circuit 525 and the solenoid driving circuit 524 based on the command value of each finger received through communication with the command generator 506. To do. At this time, the control value output to the motor drive circuit 525 is the control value detected by the encoder 341 and the current detection unit 526 in consideration of the position of each finger and the current value flowing through the motor 304 to the motor drive circuit 525. Output.

  In this embodiment, the finger part control board 520 is disposed on each finger part 306, 307, 308, respectively, and the command generator 506 and the finger part control disposed on each finger part 306, 307, 308 are provided. The board 520 is connected by a bus.

  The command generator 506 transmits the generated command value information to each finger control board 520 and then transmits the command execution command to each finger control board 520 so that each finger control board 520 is synchronized. Execute control.

  As a response to the transmitted command execution command, the command generator 506 transmits the angle information of the motor rotation shaft from each finger control board 520, current information detected from the motor, status and error, alarm information, etc. to the calculator 522 and the communication Receive via the driver 523. Communication between the command generator 506 and each finger control board 520 is performed at a cycle of 2 milliseconds to execute a gripping operation.

  With the configuration described above with reference to FIGS. 3 and 4, the fingers 306, 307, and 308 can be moved closer to or away from each other, and the fingers can be rotated, or the rotation can be locked using a lock mechanism. . Hereinafter, a gripping operation using the robot hand body 300 in this embodiment will be described in detail.

  5 and 6 are flowcharts relating to a gripping operation using the robot hand body 300 in the present embodiment. FIG. 7 is a state diagram in each step of FIGS. FIG. 7 is a view of the xy plane in the coordinate system of FIG. 2 as viewed from the plus direction of the Z axis.

  As shown in FIG. 5, first, the fingers 310, 307, and 308 are moved in the outer peripheral direction of the robot hand body 300 by driving the motor 310 in the process of S301, until the work W1 can be placed between the fingers. Open (FIG. 7A).

  Subsequently, in the process of S302, the robot hand body 300 is moved to a position where the workpiece W1 can be gripped (FIG. 7B). In this embodiment, the robot hand main body 300 is installed as an end effector of the robot arm main body 200, and moves to the sky of the workpiece W1 by the operation of the robot arm main body 200.

  Next, in the process of S303, by driving the motor 310, each finger part 306, 307, 308 is moved in the inner peripheral direction of the robot hand body 300, and the operation of closing until each finger part comes close to the workpiece W1 is performed. (FIG. 7 (c)).

  Here, the position close to the workpiece W1 is set in advance, and each finger part is moved to the set position by detecting and controlling by the encoder 311 provided in the motor 310. A method is used in which the current detection unit 514 detects the drive current value of the motor 310 and moves each finger to a predetermined position by comparing a preset motor drive current threshold value with a detected value of the motor drive current value. May be.

  Next, in the process of S304, the operation in which the finger parts approach each other around the point C is stopped, and in the process of S305, the lock of the motor 304 of each finger part by the solenoid 303 of the finger parts 306 and 307 is turned off. The rotation is free (FIG. 7D).

  In this embodiment, the finger portions that are free to rotate are two fingers of the finger portions 306 and 307, and one finger (finger portion 308) holds the rotation restrained state by the solenoid 303.

  Subsequently, in step S306, the fingers 306 and 307 that have become freely rotatable and the finger 308 that is rotationally restricted are moved at a constant speed by speed control in the closing direction again to grip the workpiece W1 (FIG. 7E). ).

  At that time, the workpiece W1 follows the contact surface of the rotation-constrained finger 308, and the freely rotatable fingers 306 and 307 rotate according to the copying operation of the workpiece W1 (FIG. 7F). Thereby, the workpiece | work W1 can be made to contact in the predetermined position used as the plane of each finger part.

  Next, it is determined whether the gripping is completed in the process of S307. FIG. 6 is a flowchart showing the process of S307 in more detail.

  From FIG. 6, the moving speed of each finger part 306, 307, 308 is set to Vr until the gripping of the workpiece W1 is completed in the process of S401. The moving speed of each finger part 306, 307, 308 is appropriately set according to the shape and flexibility of the workpiece to be gripped.

  Subsequently, a drive current threshold Ith of the motor 310 that detects completion of gripping of the workpiece W1 is set in the process of S402. In this embodiment, since the torque is generated by the motor 310 when the finger is moved at a constant speed and comes into contact with the workpiece to be gripped, the gripping is completed by detecting that the required driving current increases. did. The drive current threshold Ith of the motor 310 is appropriately set according to the flexibility of the workpiece to be gripped.

  Next, the position Pm of each finger part 306, 307, 308 is calculated from the rotation angle of the motor 310 acquired by the encoder 311 in the process of S403, and in the process of S404, the position Pm of each finger part acquired in the previous control cycle is calculated. The current velocity Vm of each finger is calculated from the position Pold.

  Next, in S405, speed control is executed based on the moving speed Vr of each finger set in the process of S401 and the speed Vm of each finger calculated in the process of S404.

  Next, after storing the position Pm of each finger in the process of S406, the drive current Im of the motor 310 during the speed control in S405 is acquired in the process of S407.

  In step S408, the driving current threshold Ith for detecting completion of gripping set in advance is compared with the driving current value of the motor 310.

  Here, if the drive current value Im of the motor 310 does not exceed the drive current threshold Ith for detecting gripping completion, S408: NO, returns to immediately before the process of S403, and continues from the process of S403 to the process of S408 again. .

  If the drive current value Im exceeds the drive current threshold value Ith, S408: YES, and the process proceeds to S308 as gripping completion.

  Returning to FIG. 5, if S307 is NO, the process returns to immediately before S306, and the movement of each finger unit 306, 307, 308 is continued.

  S308: If the completion of gripping is detected in YES, the movement of each finger unit 306, 307, 308 is stopped in the process of S308. The movement of each finger is stopped by speed control with the moving speed Vr = 0, or position control with the position of each finger at the completion of gripping as the position target value.

  In the process of S309, the grip of the workpiece W1 is completed by restricting the rotation of the finger portions 306 and 307 by the solenoid 303 (FIG. 7 (g)).

  As described above, according to the present embodiment, when gripping a workpiece, the finger portion in contact with the workpiece is brought into contact with the workpiece in a freely rotating state, and the finger portion in a freely rotating state according to the shape of the workpiece. Rotates, and any workpiece can be brought into contact at a predetermined contact position.

  Further, since the workpiece follows the finger 308 as a reference by bringing at least one finger (in the above, the finger 308) into contact with the finger 308 in a state where the rotation cannot be freely performed, the gripping center position of the workpiece is large. Misalignment can be reduced.

  Furthermore, in this gripping state, a stable gripping state can be maintained by restricting the rotation of the finger part by the lock mechanism, and the displacement of the contact position between the workpiece and the finger part can be reduced with a simple and inexpensive mechanism. Various workpieces can be gripped stably.

(Second Embodiment)
In the first embodiment described above, the rotation of the finger portions 306, 307, and 308 is used to follow the workpiece and the finger portion when contacting the workpiece, and the finger portion 306, 307, 308 is contacted at a predetermined position of the finger portion. Absent. For example, a plurality of different contact surfaces can be provided for each finger, and the contact surfaces can be selected according to the workpiece to be gripped.

  In the following, the hardware and control system components different from those of the first embodiment will be illustrated and described. The same parts and operations as those of the first embodiment can be performed and the detailed description thereof will be omitted.

  In this embodiment, similarly to the first embodiment shown in FIG. 1, the robot system 100 is used and the same robot hand body 300 is used. Differences from the first embodiment are the finger portions 306, 307, and 308.

  FIG. 8 shows a finger part 306a used in this embodiment. It is assumed that the other finger portions in this embodiment have the same configuration as that in FIG.

  A contact surface 701 in FIG. 8 is a first contact surface that grips a workpiece, and a contact surface 702 is a second contact surface different from the contact surface 701. The surface shapes of the first contact surface 701 and the second contact surface 702 are the first workpiece to be gripped using the first contact surface 701, and the second shape to be gripped using the second contact surface 702. The shape is suitable for the workpiece.

  The contact surfaces 701 and 702 can be selected by rotating this finger portion around the rotation axis S in the direction of arrow B by the motor 304. Moreover, it can be made to contact a workpiece | work by arbitrary contact surfaces by carrying out rotation restraint using the solenoid 303. FIG.

  In the present embodiment, three fingers of FIG. 8 are used, but one or two fingers may be used as the fingers of FIG. 8 depending on the shape of the workpiece. The workpiece gripping operation is controlled in the same manner as in the first embodiment.

  FIG. 9 is a flowchart when changing the contact surface of the finger. As a precondition, it is assumed that each finger portion of the robot hand body 300 of this embodiment is rotationally restricted by each solenoid 303.

  From FIG. 9, first, in the process of S501, the solenoid 303 functioning as a clutch that freely or restrains the rotation of each finger is driven to make each finger free to rotate.

  Subsequently, in the process of S502, each finger unit is rotated to an appropriate position so that each finger unit can be rotated and the workpiece can be gripped by the second contact surface 702. In the present embodiment, each finger unit is rotationally moved by a motor. However, in the case of using only an actuator without providing a motor, each finger unit may be manually rotated by an operator. As for the rotation angle of each finger part, a gauge or the like may be provided on each finger part in advance so that each finger part has an appropriate rotation position. An encoder may be provided as in the first embodiment.

  Subsequently, in the process of S503, the rotation of each finger is restricted and fixed by the solenoid 303 functioning as a clutch. Thereby, it can change to the 2nd contact surface 702 corresponding to a 2nd workpiece | work, and can be gripped.

  As mentioned above, according to this embodiment, a contact surface can be changed with various workpieces. Therefore, when changing the assembly product or changing the workpiece during automatic assembly, it is possible to grip a variety of workpieces without changing the entire robot hand, and avoiding fluctuations in the teaching position due to the replacement of the entire robot hand. In addition, productivity can be improved.

(Modification)
A modification of this embodiment is shown in FIG. FIG. 10 is a view of the xy plane of the coordinate system of FIG. 8 as seen from the plus direction of the Z axis.

  FIG. 10 (a) is a contact surface in which the contact surface 701a is a flat surface, and 702a is a modification in which an acute concave portion is formed.

  FIG. 10B is a contact surface in which the contact surface 701b is planar, and 702b is a modification in which curved convex portions are formed.

  FIG. 10C is a contact surface in which the contact surface 701c is planar, and 702c forms a curved concave portion.

  FIG. 10D shows a modification in which three contact surfaces 701d, 702d, and 703d having different shapes are provided, and FIG. 10E shows contact surfaces 701e, 702e, and 703e having different shapes. This is a modification in which four surfaces 704e are provided.

  In addition, this modification is not limited to these, You may provide the contact surface of various shapes according to the number of the workpiece | work used as the holding object.

(Other embodiments)
Moreover, although the case where the robot arm main body 200 is a joint robot arm is described in the above embodiment, the number of joints is not limited to this. Although the vertical multi-axis configuration is shown as the type of the robot arm main body 200, a configuration equivalent to the above can also be implemented in the joint of the robot arm main body 200 of a different type such as a parallel link type.

  Also, the number of finger units installed is not limited to the number shown in the above embodiment, and may be two, for example, or four or more.

  In the above-described embodiment, the detection of completion of gripping is detected by the current value of the motor. However, the present invention is not limited to this. In this case, the value of the reaction force generated at the finger when the workpiece is gripped is detected by the force sensor, and the gripping is completed when the value of the reaction force exceeds a preset threshold value.

  The processing procedures of the first embodiment and the second embodiment described above are specifically executed by the robot hand control device 500. Therefore, it can be configured to be achieved by supplying a recording medium recording a software program capable of executing the above-described functions to the robot hand control device 500, and reading and executing the program stored in the recording medium by the CPU 501. . In this case, the program itself read from the recording medium realizes the functions of the above-described embodiments, and the program itself and the recording medium on which the program is recorded constitute the present invention.

  In each embodiment, the case where the computer-readable recording medium is ROM or RAM and the program is stored in ROM or RAM has been described. However, the present invention is not limited to such a form. The program for carrying out the present invention may be recorded on 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 a recording medium for supplying the program.

DESCRIPTION OF SYMBOLS 100 Robot system 200 Robot arm main body 300 Robot hand main body 301 Palm part 302 Mounting part 303 Solenoid 304, 310 Motor 305 Guide rail 306, 307, 308 Finger part 309 Restriction part 311, 341 Encoder 400 System control apparatus 500 Robot hand control apparatus 600 Robot arm controller 506 Command value generator 507 Position control block 508,511 switching block 509 Differentiation block 510 Speed control block 512 Current control block 514,526 Current detection unit 520 Finger control board 521 Power supply circuit 522 Calculator 523 Communication driver 524 Solenoid drive circuit 525 Motor drive circuit 701 First contact surface 702 Second contact surface

Claims (13)

A robot hand that includes a plurality of fingers and grips an object with the fingers,
A drive mechanism for moving the fingers close to or away from each other;
A support mechanism for rotatably supporting at least one of the fingers;
A locking mechanism that disables rotation of at least one of the fingers;
A control device for controlling the drive mechanism, the support mechanism, and the lock mechanism;
The controller is
With the drive mechanism, in a state where at least one of the fingers can rotate, the fingers are brought close to the object,
A robot hand, wherein the support mechanism is locked by the lock mechanism after the finger portion approached comes into contact with the object. The robot hand according to claim 1, wherein
The controller is
With the locking mechanism, at least one finger part of the finger parts cannot be rotated, and the other finger parts can be rotated, and the finger parts are brought close to the object,
A robot hand that controls to lock the support mechanism by the lock mechanism after all the finger parts contact the object. In the robot hand according to claim 1 or 2,
The support mechanism includes a drive source for rotating the finger part,
The controller is
A current detection unit for detecting a value of a current flowing through the drive source;
A robot hand that locks the support mechanism by the lock mechanism when a predetermined value is detected by the current detection unit. In the robot hand according to claim 1 or 2,
A force detecting means for detecting a reaction force generated in the finger portion when the finger portion and the object are in contact with each other;
The controller is
A robot hand that locks the support mechanism by the lock mechanism when a predetermined value is detected by the force detection means. In the robot hand according to any one of claims 1 to 4,
The finger portion has a plurality of types of contact surfaces,
The robot hand characterized in that the contact surface to be brought into contact with the object can be selected by the drive source.   A robot apparatus comprising the robot arm according to any one of claims 1 to 5 in a robot arm. A method for controlling a robot hand comprising a plurality of fingers and gripping an object by the fingers,
The robot hand is
A drive mechanism for moving the fingers close to or away from each other;
A support mechanism for rotatably supporting at least one of the fingers;
A lock mechanism that locks the support mechanism and renders at least one of the fingers unable to rotate,
An approaching step of causing the finger to approach the object in a state where at least one of the fingers can be rotated by the drive mechanism;
A contact step of bringing the finger part approached into contact with the object;
And a locking step of locking the supporting mechanism of the finger portion by the locking mechanism. The control method according to claim 7,
In the approaching step, at least one finger part among the finger parts cannot be rotated by the lock mechanism, and the other finger parts can be rotated, and the finger parts are brought close to the object,
The control method is characterized in that the locking step locks the support mechanism of the finger portion that is brought close to the object in a state where it can rotate after all the finger parts contact the object. The control method according to claim 8, wherein
The support mechanism includes a drive source for rotating the finger part,
The robot hand includes a current detection unit that detects a value of a current flowing through the drive source,
The control method characterized in that the locking step locks the support mechanism by the lock mechanism when a predetermined value is detected by the current detection unit. The control method according to claim 8, wherein
The robot hand has force detection means for detecting a reaction force generated in the finger part when the finger part and the object come into contact with each other.
The control method characterized in that the locking step locks the support mechanism by the lock mechanism when a predetermined value is detected by the force detection means. A method of assembling an article using a robot hand that includes a plurality of fingers and grips an object with the fingers,
The robot hand is
A drive mechanism for moving the fingers close to or away from each other;
A support mechanism for rotatably supporting at least one of the fingers;
A lock mechanism that locks the support mechanism and renders at least one of the fingers unable to rotate,
An approaching step of causing the finger to approach the object in a state where at least one of the fingers can be rotated by the drive mechanism;
A contact step of bringing the finger part approached into contact with the object;
A locking step of locking the support mechanism of the finger by the lock mechanism;
An assembling method for assembling the grasped object to another object.   A control program capable of executing the control method or the article assembly method according to any one of claims 7 to 11.   A recording medium capable of reading the control program according to claim 12 by a computer.

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