JP3202456B2 - Control device for hand mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a hand mechanism for causing a finger of a robot hand mechanism to perform a gripping operation.

[0002]

2. Description of the Related Art Conventionally, in a robot hand mechanism, as shown in FIG. 11, when a gripping operation is completed or failed, a load sensor is attached to a work contact surface of a finger, a strain gauge or a proximity sensor is attached to a finger. Then, the discrimination is made using those outputs.

[0003]

However, in the above-mentioned conventional example, since a load sensor, a strain gauge, a proximity sensor, and the like are attached to the finger, it is costly, takes up space, and requires an amplifier for an output signal. ,
As a result, there has been a problem that the apparatus itself becomes large-scale, complicated, and low in practicability. In addition, there is also a problem that there is no highly reliable strain gauge itself.

[0004] In addition to the above problems, there are also the following problems. That is, in the conventional robot hand mechanism, when controlling the gripping force of the finger, it is necessary to externally set the target gripping force and the direction in which the gripping force is to be generated. More specifically, for example, as shown in FIG. 12, data for discriminating between gripping force control and positioning control, data for a target position and data for a target speed, which are data for positioning control, and data for gripping force control. A total of five data, that is, data of a certain target gripping force and data of a direction in which the gripping force is generated, must be externally input to the control device. Therefore, a space for storing such a large number of data is required in the control device, and there is a problem that the storage area in the control device is not efficiently used. In addition, when inputting data on the direction in which the gripping force is generated, there is another problem that it is confusing to determine which is the + direction and which is the-direction.

Accordingly, the present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to provide a hand mechanism capable of judging success or failure of grasping without attaching a sensor or the like to a finger. It is to provide a control device. A second object of the present invention is to provide a control device for a hand mechanism that can reduce the number of data input from the outside.

[0006]

In order to solve the above problems and achieve the object, a control device for a hand mechanism according to the present invention comprises a driving source for moving a finger and a driving force of the driving source. A control device for a hand mechanism for controlling a robot hand mechanism including a transmitting unit for transmitting to the finger and a position detecting unit for detecting a current position of the finger, wherein the finger grips a workpiece. A first target position setting means for setting a first target position for moving the finger, and moving the finger toward the first target position while maintaining the gripping force of the finger at a predetermined gripping force. Gripping force control means for controlling the driving source, speed detecting means for detecting the moving speed of the finger based on the output of the position detecting means, and the predetermined gripping means by the speed detecting means. After it is detected that the moving speed of the finger maintained at the force becomes zero, the current position of the finger is compared with the first target position to determine whether the finger has gripped the work. And a grip determination means for determining

Further, in the control device for a hand mechanism according to the present invention, the first target position is a position that falls inside the contour of the work in the direction of travel of the finger. Further, the control device for a hand mechanism according to the present invention is characterized by further comprising a gripping force setting means for setting gripping force data for generating the predetermined gripping force on the finger.

In the control device for a hand mechanism according to the present invention, the gripping force control means compares the current position of the finger with the first target position and moves the finger in either direction. It is characterized by comprising direction determining means for determining whether Further, in the control device for a hand mechanism according to the present invention, there is provided positioning control means for controlling the driving means so as to position the finger at a second target position located outside the contour of the work, A position error detection circuit for detecting a position error between the current position of the finger and the second target position based on the output of the detection means; and a current movement speed of the finger based on an output of the speed detection means and a predetermined value. And a speed error detecting circuit for detecting an error from the target moving speed.

Further, in the control device for a hand mechanism according to the present invention, the positioning control means further includes second setting means for setting the second target position and the predetermined target moving speed. And In the control device for a hand mechanism according to the present invention, a state in which the driving source is controlled by the gripping force control means;
The apparatus further comprises switching means for switching between a state in which the drive source is controlled by the positioning control means.

In the control device for a hand mechanism according to the present invention, the position detecting means is an encoder connected to the driving source. Also,
In the control device for a hand mechanism according to the present invention, the drive source is a servomotor. In the control device for a hand mechanism according to the present invention,
When the robot hand is moved by the robot,
The present invention is characterized in that a comparison between a current position of the finger and the first target position is performed at predetermined time intervals.

[0011]

As described above, since the control device for the hand mechanism according to the present invention is constituted, when the finger moves while maintaining a constant gripping force, the stop position of the finger and the first target position are determined. In comparison, when the stop position has passed the first target position, it is determined that the grip has failed. When the stop position is before the first target position, the finger abuts on the workpiece. By judging that the gripping has been completed and determining that the gripping has been successful, it is possible to determine the success or failure of the gripping without providing a special sensor or the like to the finger.

Further, by providing direction determining means for comparing the current position of the finger with the target position to determine the direction in which the finger should travel, there is no need to input the traveling direction of the finger from the outside. The amount of input data can be reduced. Also, when the hand mechanism is moved by the robot, the current position of the finger and the first
By repeating the comparison with the target position every predetermined time, it can be monitored that the hand has not missed the work.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail. <System Configuration> FIG. 1 shows a development example of a robot hand to which one embodiment is applied and its control device.

In FIG. 1, reference numeral 11 denotes a robot hand mechanism, reference numeral 12 denotes a finger included in the robot hand mechanism 11, which actually grips a work, and reference numeral 13 denotes a controller for controlling the robot hand mechanism 11. Reference numeral 14 denotes an assembly work robot having a robot hand mechanism, and reference numeral 15 denotes a controller that controls the assembly work robot 14. Reference numeral 16 is connected to a controller 13 for controlling the robot hand mechanism 11, and registers data such as a target position, a target speed, and a gripping operation for operating the robot hand mechanism 11 in a teaching data table of the controller 13 of the robot hand mechanism. And a teaching device capable of operating the robot hand mechanism 11 directly. Reference numerals 17 and 18 denote interfaces of respective controllers.

FIG. 2 is a view showing a robot hand mechanism. In FIG. 2, 101 is a servo motor, 102 is a pulse encoder for position detection connected to the servo motor 101, 103 is a timing pulley attached to a rotary output shaft of the servo motor, 104 is a timing belt,
Reference numeral 105 denotes a timing pulley located on the opposite side of the pulley 103, and reference numeral 106 denotes a ball screw having both left and right threads cut. 107 and 108 are linear guides;
Reference numeral 10 denotes a finger portion which is a movable portion to which a nut (not shown) for the ball screw 106 is attached, and 11
Reference numerals 1 and 112 denote finger stoppers separately attached to the finger portion and the fixed frame 113. Reference numeral 115 denotes an origin sensor for determining the origin position of the finger portion. Reference numeral 114 denotes a mounting flange for mounting the entire robot hand mechanism to the tip of the industrial robot.

The operation of the robot hand mechanism transmits the rotation output of the servo motor 101 to the timing pulley 103, the timing belt 104, and the timing pulley 105, and rotates the ball screw 106. As a result, the finger portions 109 and 110 can move linearly in a direction away from or in the direction of approaching, and the workpiece can be gripped by these two fingers. Also, the servo motor 101
The positions of the finger portions 109 and 110 can be detected by the pulse encoder 102 attached to the oscilloscope. Further, the position origin of the finger portions 109 and 110 can be set with reference to the origin sensor 115. When the finger portions 109 and 110 move away from each other, the stopper 112 of the finger 110 and the stopper 111 of the frame 113 come into contact before the finger 109 comes into contact with the frame 113.

<Overall Operation> Next, the robot hand mechanism 1
1. The overall operation of the controller 13 of the robot hand mechanism, the robot 14 for assembly work, and the controller 15 of the robot for assembly work will be described. First, the assembling robot controller 15 controls the assembling robot 1 in order to hold the target workpiece by the robot hand mechanism 11.
4 is operated. Next, the assembly work controller 15
Is actually input to the finger 1 from the input / output interface 17.
2 outputs an operation signal pattern for gripping a target work.

FIG. 3 shows this operation signal pattern. In the present embodiment, as shown in FIG. 4, eight patterns are prepared. The configuration of each pattern is as shown in FIG.
A "start bit" consisting of four bits and indicating the start of an operation (in FIG. 4, indicated by a symbol with a hatched circle)
And three operation type bits. In this embodiment, the operation is not started when the start bit is “0”, regardless of the type of the operation type bit. When the start bit is “1”, the operation set by the operation type bit, for example, the operation indicated by n = 0, 1, 2,... 7 in FIG.

FIG. 4 exemplifies eight kinds of operation commands to the finger. The three operation type bits determine the value of the operation pattern n. Eight operation patterns from n = 0 to n = 7 are set. For example, n = 0 of the pattern indicates the operation "origin setting" operation with n = 1 and a pattern is that moves at a speed V ₁ to the position X _1.

The operation with n = 2 of the pattern is of a case of gripping the workpiece, from the current position of the finger (standby position) to operate the finger toward the target position X _2, a workpiece It is to grasp.
Then the target position X ₂ as gripping reference position, the gripping complete as compared to the current position to determine failure. Data after n = 3 is the same as n = 1 and 2.

The number of bits may be further increased in order to increase the number of point data. The table in FIG. 4 stores the RA in the controller 13 so that search and read are possible.
M. Robot hand mechanism controller 13
Is a signal corresponding to data such as a target position, a target speed, and a gripping operation which are input in advance from the input / output interface 18 and which are recorded in the teaching data table in the robot hand mechanism controller 13 by the teaching device 16 in advance. The same pattern is selected, the finger 12 starts the operation indicated by the data, and performs the positioning operation and the work gripping operation.

Next, when the finger 12 actually performs the target positioning operation and the work gripping operation, the robot hand mechanism controller 13
The operation completion signal is output to the assembly work robot controller 15 and the completion signal is taken in from the input / output interface 17.
Starts the next operation of the assembly robot 14.

<Teaching Device> FIG. 5 shows an example of an operation panel of the teaching device 16 for the robot hand mechanism. 61 is the current value and the teaching data display unit of the fingers 12, 62 are current values taken from the robot hand mechanism controller 13 is shown during operation completion of the fingers 12, Point1,2 in 63, ... 2 ^n-1 - Reference numeral 1 denotes a point name at which the finger 12 is to operate, and corresponds to the above-mentioned bit pattern n = 1, 2, 3,... 7 (in the case of 4 bits).

Numeral 64 indicates the location of data that can be taught at the time of teaching operation. 65 is a numeric keypad for directly inputting teaching data, 66 is a key for directly selecting a position component, a speed component, and a gripping component when performing teaching work, and 67 is 6
Reference numeral 68 denotes a key used to move the cursor 4 up, down, left, and right, and reference numeral 68 denotes a registration key for determining each data taught.

FIG. 6 shows an example of a screen display of the teaching device.
(A) shows the case of the positioning operation command, and (b) shows the case of the gripping operation command. The current position is displayed on the first line, and the point data is displayed after the second line (Point1, Point1).
Point2, ...). The components of the data are the target position, the target speed, and the grip.

In the case of (a), the target position + 0010.00
Means that the positioning operation is performed at the target speed of 100%. In the case of (b), from the current position to the target position + 001
This means that the gripping motion difference is performed in the direction of 5.00. “NO” and “YES” of the grip item indicate data for determining whether or not to perform the grip operation. In this case, the positioning operation is performed by displaying "NO",
The gripping operation is performed by ES ”. The target position data when the gripping operation is performed includes a role of a reference value for determining a moving direction of the finger for performing the gripping operation, and completion of the gripping operation or failure of the gripping operation. Has two roles as a role of a reference value for judging.

The item of the target speed in the gripping operation has not been set. This is because, in the gripping operation, it is meaningless to specify a speed in order to control the gripping force to a predetermined value. As another method of setting gripping data, gripping force data can be directly set. In this case, “0” is set in the gripping item in the case of positioning control, and other than “0” in the case of gripping force control, gripping force data (for example, 3k) that can generate a target predetermined gripping force on the finger is set.
If a grip force of gf is desired, a method of setting numerical data (absolute value data) corresponding thereto can be considered.

In the above example, each data is handled as point data, but it is also possible to describe this in the form of an operation program. The teaching device may be a personal computer or the like. In that case, the display format is not specified. FIG. 7 is a control block diagram relating to a gripping force control method of the hand mechanical mechanism. FIG. 7 includes two loops: a positioning control loop (shown by a solid frame in the figure) and a gripping force control loop (shown by a broken frame in the figure). The positioning control loop is a loop for positioning the finger at the “preparation position”, and the gripping force control loop is a loop for controlling the gripping force generated by the finger after the finger is placed at the preparation position.

Positioning Control First, a positioning control loop will be described. In the figure, a command position register 1 is a register that stores a target command position. The target command position from the command position register 1 is output to the adder 2. The adder 2 obtains a position deviation between the target command position and the current position of the finger, and outputs the position deviation to the position loop gain multiplier 3. The position loop gain multiplier 3 calculates a target speed by multiplying the position deviation by a predetermined control gain, and outputs the target speed to the adder 4. The adder 4 calculates a speed deviation between the input target moving speed and the current moving speed of the finger, and outputs the result to the speed loop gain multiplier 5. The speed loop gain multiplier 5 multiplies the input speed deviation by a predetermined control gain, and outputs a target command current to the adder 7. The adder 7 calculates a current deviation between the input target command current and the current command current currently output to the servo motor 101, and calculates the current deviation.
Output to The torque amplifier 8 amplifies the input current deviation and outputs the amplified current deviation to the servo motor 101 as a command current. The servomotor 101 is driven by the input command current, generates torque, and opens and closes fingers 109 and 110 of the hand mechanism to perform positioning. The encoder 102 outputs a signal corresponding to the rotation of the servo motor 101 to the current position counter 204 in order to detect the current position of the finger portion, and outputs the signal to the current position counter 20.
4 calculates the current position based on the signal from the encoder 102 and sets the current position as the current position. Also, the current position counter 204
Is output as the current speed through the differentiator 13. These are the conventional positioning control loops.

The gripping force control Next, the operation for fingers actually grip the object work is performed as follows. By the above-described position control, the finger is held at a standby position for gripping the work (this standby position is a position where there is some margin for the size of the target work, that is, the position of the target work and the finger when positioned there). After that, the loop switch 6 is switched from the positioning control loop side (position b in the figure) to the gripping force control loop (position a).

Then, the commanded gripping force 14 is set and output to the gripping force / torque calculation unit 15. At this time, the current position and the command position, which is the target position, are input to the direction determination circuit 20 to determine in which direction the finger should be driven. Then, the direction is output to the gripping force / torque calculation unit 15.

The gripping force / torque calculation unit 15 has a conversion function for converting a commanded gripping force into a torque (current) value. When a commanded gripping force is input, a torque (current) value required for the commanded gripping force is output from the direction determination circuit 20. Is calculated in consideration of the output result of (1) and is output as a command torque (current) value. Generally, a servomotor generates torque in proportion to a command current value,
Naturally, the torque and the force generated by the torque are in a proportional relationship, and the force generated with respect to the command current value is always in a proportional relationship. Therefore, a simple conversion function is prepared in the gripping force / torque calculation unit 15.

When the commanded gripping force is input to the gripping force / torque calculator 15, the torque is converted into a torque (current) value by the conversion function and output to the adder 7 through the loop switch 6 as a command value. Then, a constant current value control is performed by a current control loop (a loop returning from the torque amplifier 8 to the arithmetic unit 7), a constant torque is generated in the servo motor 101, the hand mechanical mechanism is operated, and the finger 10
9 and 110 are brought into contact with the object.

When the finger portion of the hand mechanism starts operating in the direction of gripping the target workpiece in accordance with the command gripping force. This time, the speed monitor 16 monitors the current speed output from the differentiator 13. Then, at the time when the current speed becomes speed = 0 (speed = 0 when the finger is in contact with the work or has moved to the movement limit position or the stopper),
Whether the gripping operation has been completed by the gripping checker 18 (whether the finger has reached the target gripping force with respect to the target workpiece and has gripped it) or has failed, has been input as a gripping reference position (a target position from the outside). ) 19 to make a comparison.

In this embodiment, the gripping force instruction is used. However, since the current constant value control is used, a method of directly inputting a command current value for a target gripping force from the beginning into the current control loop, or There is a method of giving an instruction in the form of torque. FIG. 8 shows a hardware configuration diagram of the control device. 201 is a central processing unit (CPU) for realizing control
Numeral 202 denotes a non-volatile memory (RO) which is bus-connected to the CPU 201 and includes a series of control processing algorithm programs and a man-machine interface program.
M), and 203 is a memory (RAM) backed up by a power supply capable of storing teaching data. Also, 204
Is a pulse encoder 1 connected to the servo motor 101
02 is a current value counter which is capable of counting the current position of the servomotor. Reference numeral 208 denotes a D / A converter connected to the servo motor through a torque amplifier 209, which can output an analog current value to the torque amplifier 209 according to an instruction from the CPU 201.
Reference numeral 206 denotes information on the origin sensor 115 and the external I / O 11
Information such as an operation signal pattern of the hand mechanical mechanism and an operation end signal of the hand mechanical mechanism input through
This is an I / O interface for taking in the U201. A communication interface 211 connects the external teaching device 212 and the CPU. 202, 203,
204, 206, 208, 211 are all connected to the CPU 201 by a bus 213.

FIG. 9 is a flowchart for explaining the operation of the finger. When a movement point for a finger is specified (S-1), it is determined whether the point is an origin search operation or not (S-2).
If a home search operation is requested, home search is started (S-3).
When the processing is completed, the completion of origin search is output and the processing ends (S-4).
If a request other than the home search operation is required, it is determined whether the operation is a gripping operation or a positioning operation (S-
5).

If it is determined that the operation is the positioning operation, the control loop is switched to the position control loop if the previous operation is the gripping operation. Then, the target position and the target speed are set, a normal positioning operation is started, and when the operation is completed, the completion of movement is outputted and the operation is ended (S-5 to 9). If it is determined that the gripping operation is performed, the current position of the finger is compared with a target position (hereinafter, described as Pob) of the point data (S-1).
0).

If the current position is smaller, the target gripping force is given a positive or negative direction so that the fingers can be operated in the closing direction assuming that the workpiece is gripped from the outside. In this embodiment, the value is positive (S-11). next,
The control loop is switched from the position control loop to the gripping force control loop (S-12). Then, the finger starts operating in the closing direction.

The current state is maintained until the moving amount at the time Δt becomes “0” (S-13). When the movement amount at the time Δt becomes “0”, the current position and Pob are compared (S-14). Here, if the current position is smaller than or the same as Pob, the completion is regarded as grasping completion and a completion output is performed (S-15). If the current position is larger than Pob, it is determined that the workpiece has not been gripped and a gripping error is output (S-16).

After the gripping completion output or the gripping error output, the finger operation ends. After the completion of the output and the completion of the output, the comparison between the current position and the Pob is performed at regular intervals until a command to operate the next finger is issued. It is also possible to monitor the removal of the work such as movement).
Alternatively, a similar result can be obtained by executing the same operation command again during conveyance.

In S-10, the current position is Pob
If the target gripping force is larger than the target gripping force, the target gripping force has a positive or negative direction so that the finger can be operated in a direction to open the finger as a workpiece to be gripped from the inside (for example, a hollow cylindrical workpiece). In this embodiment, the value is negative (S-18). Next, the control loop is switched from the position control loop to the gripping force control loop (S-19). Then, the finger starts operating in the opening direction.

The current state is maintained until the movement amount at the time Δt becomes “0” (S-20). When the movement amount at the time Δt becomes “0”, the current position is compared with Pob (S-21). Here, if the current position is larger than or equal to Pob, it is regarded as grasping completion, and a completion output is output (S-15). If the current position is smaller than Pob, it is determined that the workpiece cannot be gripped and a gripping error is output (S-16).

After the gripping completion output or the gripping error output, the finger operation ends. After the completion of the output and the completion of the output, the comparison between the current position and the Pob is performed at regular intervals until a command to operate the next finger is issued. It is also possible to monitor the removal of the work such as movement).
Alternatively, a similar result can be obtained by executing the same operation command again during conveyance.

The concept of the position used in the present embodiment is that the closing direction of the finger is positive and the opening direction is negative. In S-5, it can be easily determined whether the operation is the gripping operation or the positioning operation based on whether a value is set to the target gripping force of the point data of the designated point or not. For example, in the case of positioning, "0"("NO","0", etc. on the screen of the teaching device), and in the case of the gripping force operation, "1", "2" (data of the teaching device) other than "0". "+", "-" Or "CLOS"
E ”,“ OPEN ”or“ YES ”), in this case, the target gripping force is the same without being different for each point data,
The parameters are set in advance (in the form of a target gripping force, a target torque, a target current, or the like).

If it is desired to change for each point data, the target gripping force is directly set for each point data (in the form of a target gripping force, a target torque or a target current). The above description is an example, in short,
Whether the positioning operation or the gripping operation is performed may be determined from the target gripping force data of the point data.

By S-10 to S11 or S18, the current position (finger standby position before gripping the work) and Po
By comparing with b, the direction in which the finger must move to grasp the work is determined. Referring to FIG. 10, the state shown in FIG. 10A shows a state in which the finger for gripping the work is positioned at the standby position (the position indicated by 2a). If this position is 10
mm (the position indicated by 1a is the origin position of the finger).

Next, assuming that data of 17 mm (position 4a) is set in Pob as point data for gripping the work, the finger must move to a position in the + direction from the current position. . Therefore, when switching from the positioning control loop to the gripping force control loop, the target gripping force, the target torque, or the target current has positive and negative directions so that the fingers can move in the + direction. Here, by setting the value to be positive, the motor can move the finger in the + direction.

Conversely, when gripping a hollow cylindrical work as shown in (b), the finger is positioned at the position indicated by 2b as a standby position. Next, assuming that data of 5 mm (position 4b) is set in Pob as point data for gripping the work, the finger must move to a position in the minus direction from the current position. Therefore, when switching from the positioning control loop to the gripping force control loop, the target gripping force, the target torque, or the target current has positive and negative directions so that the finger can move in the negative direction. Here, it is assumed that the motor can move the finger in the negative direction by setting to negative.

When the target gripping force including the direction in which the finger is to operate is set, the control is switched to a control loop, and the gripping operation is started. In S-13 and S20, since the counter is still operating even after the control loop is switched, "0" is monitored while monitoring the amount of change during the time .DELTA.t.
It holds the current situation until it becomes. If the change amount of the counter becomes “0” without the finger moving during the time Δt,
Compare the current position with Pob (4a, 4b) (S-14)
Or 21). If the finger was moving in the + direction,
If the current position (3a) is smaller than Pob, it is assumed that the finger gripping operation has been completed. The current position is Po
If it is larger than b, it is determined that the finger has not reached the movement limit position or the stopper because the finger cannot grip the work, and it is determined that the gripping operation has failed.

When the finger is moving in the minus direction,
If the current position (3b) is larger than Pob, it is determined that the finger gripping operation has been completed. The current position is Po
If it is smaller than b, it is determined that the finger has not reached the movement limit position or the stopper because the finger cannot grip the work, and it is determined that the gripping operation has failed. When setting the gripping operation, the setting value of Pob is, in the case of FIG. 10A, a position inside (larger) than the position of the finger when the workpiece is gripped, and a movement limit position and a position of the stopper. Outside (small) position. In the case of FIG. 10B, the position is set outside (small) of the finger when the work is gripped, and inside (large) of the movement limit position and the position of the stopper. Here, the position is described as being large or small, but this varies depending on the predetermined polarity of the motor or the transmission system of the mechanism.

That is, the set value of Pob in the case of the gripping operation is determined at the same time when the direction in which the finger is to be moved is determined.
It has the meaning of two reference values for determining the completion of the gripping operation or the failure of the gripping operation. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

The present invention can be applied to a modification or modification of the above embodiment without departing from the gist of the invention.

[0053]

As described above, according to the control device for a hand mechanism of the present invention, when the finger moves while maintaining a constant gripping force, the stop position of the finger is compared with the first target position. If the stop position has passed the first target position, it is determined that the grip has failed, and the stop position is determined to be the first target position.
If the finger is located just before the target position, it is determined that the finger has come into contact with the workpiece and stopped, and it is determined that the grip has been successfully performed. Thus, the success or failure of the grip is determined without providing a special sensor or the like on the finger. be able to.

Further, by providing direction determining means for comparing the current position of the finger with the target position and determining the direction in which the finger should travel, there is no need to input the traveling direction of the finger from the outside, so that the control device is not required. The amount of input data can be reduced. Also, when the hand mechanism is moved by the robot, the current position of the finger and the first
By repeating the comparison with the target position every predetermined time, it can be monitored that the hand has not missed the work.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a development example of a robot hand and a control device thereof according to an embodiment.

FIG. 2 is a view showing a robot hand mechanism.

FIG. 3 is a diagram showing an operation signal pattern for gripping a work.

FIG. 4 is a diagram illustrating an example of an operation command for a finger.

FIG. 5 is a diagram illustrating an example of an operation panel of the teaching device for a robot hand mechanism.

FIG. 6 is a diagram showing an example of a screen display of the teaching device.

FIG. 7 is a control block diagram relating to a gripping force control method of the hand mechanical mechanism.

FIG. 8 is a hardware configuration diagram of a control device.

FIG. 9 is a flowchart illustrating the operation of a finger.

FIG. 10 is a diagram showing a relationship between a shape of a work and a standby position of a finger.

FIG. 11 is a diagram showing a conventional example.

FIG. 12 is a diagram showing a conventional example.

[Description of Signs] 11 Robot hand mechanism 12 Finger 13 Controller 14 Robot for assembly work 15 Controller 16 Teaching device 17, 18 Interface

────────────────────────────────────────────────── (5) References JP-A-4-164589 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B25J 3/00-3/10 B25J 9 / 10-9/22 B25J 13/00-13/08 B25J 19/02-19/06 B25J 15/00

Claims (10)

(57) [Claims] A driving source for moving the finger;
A control device for a hand mechanism for controlling a robot hand mechanism including a transmitting unit for transmitting a driving force of the driving source to the finger, and a position detecting unit for detecting a current position of the finger. A first target position setting means for setting a first target position for the finger to grip a workpiece; and a first target position setting means for maintaining the gripping force of the finger at a predetermined gripping force. Gripping force control means for controlling the drive source to move the finger toward; speed detection means for detecting a moving speed of the finger based on an output of the position detection means; After it is detected that the moving speed of the finger maintained at a predetermined gripping force becomes zero, the present position of the finger is compared with the first target position, and the A control device for a hand mechanism, comprising: gripping determining means for determining whether or not the gripper grips the work. 2. The control device for a hand mechanism according to claim 1, wherein the first target position is a position that falls inside a contour of the work in a traveling direction of the finger. 3. The control device for a hand mechanism according to claim 1, further comprising grip force setting means for setting grip force data for generating the predetermined grip force on the finger. 4. The apparatus according to claim 1, wherein the gripping force control unit includes a direction determining unit that compares a current position of the finger with the first target position and determines in which direction the finger is to be moved. The control device for a hand mechanism according to claim 1, wherein: 5. The method according to claim 5, wherein the second position is located outside the contour of the workpiece.
Positioning control means for controlling the driving means so as to position the finger at the target position, wherein a position error between a current position of the finger and the second target position is determined based on an output of the position detection means. Positioning control means further includes a position error detection circuit for detecting, and a speed error detection circuit for detecting an error between a current moving speed of the finger and a predetermined target moving speed based on an output of the speed detecting means. The control device for a hand mechanism according to claim 1, wherein: 6. The hand mechanism according to claim 5, wherein said positioning control means further comprises second setting means for setting said second target position and said predetermined target moving speed. Control device. 7. A switching device for switching between a state in which the driving source is controlled by the gripping force control unit and a state in which the driving source is controlled by the positioning control unit. The control device for a hand mechanism according to claim 5, wherein 8. The control device for a hand mechanism according to claim 1, wherein said position detecting means is an encoder connected to said drive source. 9. The control device according to claim 1, wherein the driving source is a servomotor. 10. The hand according to claim 1, wherein when the robot hand is moved by the robot, a comparison between a current position of the finger and the first target position is performed at predetermined time intervals. Mechanism control device.