JP2018001359A - Control method of hand robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent holding performance while saving power usage.SOLUTION: A control method of a hand robot comprises: a first step for energizing multiple motors 21a of a finger body 21 in a predetermined order, to bend respective joints corresponding to the motors 21a ; a second step, each time when touch sensor means detects a touch, for stopping energizing a motor 21a of a joint corresponding to the touch sensor means that detects the touch to lock the joint corresponding to the touch sensor means that detects the touch through a one-way power transmission mechanism 21c; a third step, on condition that all motors 21a have become non-energized, for energizing a predetermined motor 21a to bend a joint corresponding to the predetermined motor 21a; and a fourth step, on condition that a holding force based on a detected value of the touch sensor means has become a target holding force, for stopping energizing all motors 21a including the predetermined motor 21a, to lock all joints.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for controlling a hand robot in which a joint between adjacent nodes is bent and extended.

  Conventionally, in this kind of invention, there is a hand robot provided with a plurality of fingers, for example, as described in Patent Document 1. This hand robot includes a plurality of nodes (links) constituting each finger, a plurality of gears, a reducer, a motor, and the like, and each finger is bent or stretched by driving the motor.

JP 2007-152528 A

By the way, in the prior art, as illustrated in FIG. 7, a plurality of nodes (links) are connected so as to bend and extend at joints between adjacent nodes, and correspond to each joint. A plurality of motors are provided.
In such a conventional hand robot, it is necessary to appropriately select the plurality of motors so that fingertip force is generated by torque (bending force) of all joints. The maximum fingertip force depends on the torque of the motor that generates the minimum bending force among the plurality of motors.
Usually, the required torque (bending force) of the joint is increased toward the base side of the finger, so that the mechanism is easily increased in size.
In addition, when a gripping object is gripped by a plurality of fingers, it is necessary to continue supplying power to the plurality of motors in order to maintain the gripping state.
Therefore, each joint is provided with a one-way power transmission mechanism that can transmit the driving force from the motor side to the output side and lock when the force is applied from the output side. However, since a special mechanism is required, it is necessary to devise a control in order to obtain a good gripping performance.

In view of such problems, the present invention has the following configuration.
Fingers for flexing and extending a plurality of joints, motors provided for each of the joints, power applied to the input unit from the motor side provided for each motor can be transmitted to the output unit, and the output from the output side When a force is applied to the part, a one-way power transmission mechanism that locks the output part, a bending / extension mechanism that flexes and extends the corresponding joint by the power of the output part, and the finger grips the object to be grasped Of a hand robot provided with an elastic portion provided at a portion where a gripping force is applied and a tactile sensor means provided for each joint to sense a reaction force when the joint is bent. A control method comprising: energizing a plurality of motors of the finger in a predetermined order to bend the joint corresponding to each motor; and whenever there is sensing by the tactile sensor means, A second step of de-energizing the joint motor corresponding to the known tactile sensor means to lock the joint by the one-way power transmission mechanism, and on condition that all the motors are de-energized The predetermined motor is turned on condition that a third step of energizing the predetermined motor to bend the joint corresponding to the motor and that the gripping force based on the detection value of the tactile sensor means becomes the target gripping force. And a fourth step of deenergizing all the motors including the fourth step to lock all the joints.

  Since the present invention is configured as described above, it is possible to obtain good gripping performance with power saving.

It is a structural diagram showing an example of a hand robot. It is the schematic which shows an example of a hand part. It is a principal part structure figure of a finger. It is a flowchart which shows an example of the control method of the hand robot which concerns on this invention. It is a schematic diagram which shows an example of operation | movement of a finger body to (I)-(III) sequentially. It is a schematic diagram which shows the finger body in the other example of a hand robot. It is a schematic diagram which shows the finger body in the conventional robot hand.

The first feature of the present embodiment is that a finger that flexes and extends a plurality of joints, a motor provided for each joint, and power that is provided for each motor and is applied to the input unit from the motor side is output. A unidirectional power transmission mechanism that locks the output section when a force is applied to the output section from the output side, and a bending / extension mechanism that flexes and extends the corresponding joint by the power of the output section And an elastic portion provided at a portion where a gripping force acts when the finger body grips an object to be gripped, and a reaction force provided when the joint is bent is detected for each joint. A hand robot control method comprising tactile sensor means, wherein a first step of bending the joints corresponding to each motor by energizing a plurality of motors of the finger in a predetermined order; and Tactile sensor hand A second step of de-energizing the motor of the joint corresponding to the sensed tactile sensor means to lock the joint by the one-way power transmission mechanism, and On the condition that energization has occurred, a third step of energizing a predetermined motor to bend a joint corresponding to the motor, and that the gripping force based on the detection value of the tactile sensor means has become the target gripping force. The condition includes a fourth step in which all the motors including the predetermined motor are de-energized and all the joints are locked (see steps 3 to 9 in FIG. 4).
Here, the one direction in the “one-way power transmission mechanism” means the direction of power transmission from the input unit to the output unit.
In addition, the “reaction force when the joint is bent” includes a reaction force when the finger is pressed against the object to be grasped by bending of the joint and a reaction force when the joint is bent to the movable limit. Including power.
Further, the number of the “predetermined motors” is not limited, and may be one or a plurality depending on the required gripping force, the shape of the gripping object, and the like.

  As a second feature, the finger body has a movable limit when the joints are bent, and in the second step, the tactile sensor means includes a reaction force due to the movable limit, or the finger body Each time it senses that it receives a reaction force when it is pressed against the grasped object, the joint motor corresponding to the sensed tactile sensor means is de-energized and the joint is locked by the one-way power transmission mechanism. Put it in a state.

  A third feature includes an initial position detecting unit that detects an initial position of the grasped object, and a hand moving mechanism that moves a hand unit provided with a plurality of the fingers, before the first step. In addition, the initial position of the gripping object is recognized by the initial position detecting means, and the hand moving mechanism is operated in accordance with the initial position to move the hand unit to a position where the gripping object can be gripped. (See steps 1 and 2 in FIGS. 1 and 4).

  The fourth feature is that, as a preferable aspect for gripping an object to be gripped that is larger than that of the hand unit, in the first step, a plurality of motors in the finger body are sequentially energized from the root side. Thus, the joint of the finger body is bent in order from the root side of the finger (see FIG. 5).

  As a fifth feature, as a preferable aspect for gripping a target object that is smaller than the hand part in particular, by energizing a plurality of motors in the finger in order from the fingertip side, The joint is bent in order from the fingertip side.

  As a sixth feature, there is provided a movement detecting means for detecting a relative movement of the grasped object with respect to the finger, and whether or not the grasped object is moved by the movement detecting means after the fourth step. If there is a movement, the target gripping force is corrected so as to increase in accordance with the movement, and the process returns to the third step (see step 11 and subsequent steps in FIG. 4).

<Specific Embodiment>
Next, specific embodiments having the above characteristics will be described in detail with reference to the drawings.
FIG. 1 schematically shows an example of a hand robot A according to the present invention.
This hand robot A includes a hand moving mechanism 10 in which a plurality of arms 14 are connected to a support rod 12 fixed on a base 11 via a joint portion 13 so as to be able to bend and extend, and the hand moving mechanism 10 includes: The hand unit 20 connected to the arm 14 on the most advanced side, the control unit 30 for controlling the hand moving mechanism 10 and the hand unit 20, and the gripping object detection means for detecting the initial position and movement of the gripping object X 40.

The plurality of arms 14 are configured to bend and extend between adjacent arms or between the arm 14 and the support rod 12 by a motor and gear mechanism (not shown).
A part or all of these arms 14 may be rotated about the longitudinal direction as necessary in addition to the bending and extending movement. Similarly, the support rod 12 may be rotated about the longitudinal direction as necessary.

  The hand moving mechanism 10 is not limited to the illustrated example as long as it is a mechanism that moves the hand unit 20 to a target position. As another example, the number of the joint units 13 and the arms 14 is different from that illustrated. In addition, it is possible to adopt an aspect configured in a human arm shape, an aspect in which a well-known XY table (not shown), a link mechanism, or the like is combined.

  A hand unit 20 is connected to the most distal portions of the plurality of arms 14 in the hand moving mechanism 10. The hand portion 20 is provided so as to be bent and extended or rotated with respect to the arm 14 as required.

The hand unit 20 includes a plurality of fingers 21 that bend and extend a plurality of joints, and a palm 22 that supports the fingers 21.
Here, the joint means a portion where the root of the finger 21 and the palm portion 22 are connected, and a portion where adjacent node portions 1 and 2 are connected in each finger 21.

At least three finger bodies 21 are required for gripping an object, and in the preferred mode of the present embodiment, four finger bodies 21 are provided to improve grip operability.
These fingers 21 are connected to the palm 22 so that the bending direction is directed toward the center of the palm 22.

In order to generate an arbitrary three-dimensional force by these fingers 21, it is preferable to provide at least three active rotation axes a, b, c for one finger as shown in FIG. 2.
The rotation axis a is provided at the most proximal joint of the finger body 21 and inwardly rotates in the direction in which the adjacent finger bodies 21 are brought close to each other, or rotates outward in the opposite direction.
The rotation axis b is provided at the most proximal joint of the finger 21 and bends the finger 21 toward the center of the palm 22 or extends in the opposite direction.
The rotation axis c is provided at a joint between adjacent node portions 1 and 2 of the finger 21, and is opposed to the node portion 1 to bend the node portion 2 toward the center of the palm portion 22 or extend in the opposite direction. To do.

  As illustrated in FIGS. 2 and 3, each finger 21 adjusts and transmits the motor 21 a serving as a drive source and the rotational force of the motor 21 a for each joint in the nodes 1 and 2. A mechanism 21b, a one-way power transmission mechanism 21c that transmits power only in one direction, a bending / extension mechanism 21d that bends and extends a corresponding joint by the power of the one-way power transmission mechanism 21c, and the finger body 21 is an object to be grasped And an elastic portion 21e provided on a portion (a fingertip side in the illustrated example) on which a gripping force acts when gripping X.

Adjacent node portions 1 and 2 may be members having a substantially cylindrical shape with a hollow inside, and are connected so that the other is rotated with respect to one of them.
Although these node parts 1 and 2 may be formed from a rigid material, it is an elastic material (for example, rubber | gum, an elastomer resin, other elastic resin materials from a viewpoint of improving the adhesiveness at the time of holding | grip the holding | grip target object X. Etc.).

  The motor 21a is an electric rotary motor with an output shaft protruding. Specific examples of the motor 21a include a stepping motor that controls the rotation angle and a DC brushless motor.

The speed adjusting mechanism 21b is a mechanism that decelerates the rotation of the output shaft of the motor 21a at an appropriate ratio set in advance and transmits it to the input portion of the one-way power transmission mechanism 21c. For example, the speed adjusting mechanism 21b includes a planetary gear mechanism. The
Other examples of the speed adjusting mechanism 21b include a mechanism in which a plurality of gears are appropriately combined, a linear screw mechanism, a mechanism using a harmonic drive (registered trademark), a mechanism in which these mechanisms are appropriately combined, and the like. It is also possible.

The one-way power transmission mechanism 21c can transmit bidirectional rotational force applied to the input unit from the output shaft of the motor 21a to the output unit, and when the rotational force is applied to the output unit from the output side, the output unit is This is a mechanism for locking, and the corresponding joint (between the node parts 1 and 2 according to FIG. 3) is bent by the rotational force of the output part.
For the one-way power transmission mechanism 21c, for example, the invention disclosed in the republished patent WO2013 / 133162 can be used.
In addition, as another example of the one-way power transmission mechanism 21c, a worm gear mechanism, a sliding screw mechanism, an aspect in which these mechanisms are appropriately combined, or the like can be used.

The bending / extending mechanism 21d is a mechanism that bends each joint by the rotational force of the output portion of the unidirectional power transmission mechanism 21c. According to the example shown in FIG. 3, the gear 21d1 that rotates by the rotational force of the unidirectional power transmission mechanism 21c. And a male screw-like member 21d2, a nut-like member 21d3 screwed into the male screw-like member 21d2, a link member 21d4 pivotally supported by the nut-like member 21d3, a parallel link mechanism 21d5 rotated by the advancement / retraction of the link member 21d4, etc. Composed.
The bending / stretching mechanism 21d can be a known mechanism other than the illustrated example as long as it is a mechanism that bends and extends each joint.

The elastic portion 21e is disposed near the finger pad portion on the most distal side of the finger body 21, and is fixed to a receiving member 21f pivotally supported on the distal end side of the bending / extending mechanism 21d.
For the elastic body 21e, for example, a material having an appropriate elasticity such as nitrile rubber, silicon resin, urethane resin, or the like and having an appropriate friction coefficient so as not to slide the gripping object X is selected.
The elastic body 21e has a necessary minimum elasticity larger than the amount of change obtained by adding the displacement amount due to the backlash of the entire finger body 21 and the amount of elastic deformation on the drive source side relative to the elastic body 21e in the entire finger body 21. The elastic modulus is appropriately set so as to be deformed.

  Although not shown, a drive mechanism for bending and extending the finger body 21 around the rotation axis a by a mechanism similar to that described above between the most proximal side of the finger body 21 and the palm portion 22, A well-known drive mechanism that rotates the body 21 around the rotation axis b is provided, and a motor that is a drive source of each mechanism is controlled by the control unit 30.

  The control unit 30 is configured by, for example, a control circuit including a power source, a motor driver, and the like, a computer, and the like, and controls operations of the hand moving mechanism 10 and the hand unit 20 based on a program stored in the storage device.

The control unit 30 receives a reaction force when each joint of each finger 21 is bent by cooperating with a current sensor (not shown) that outputs a signal corresponding to the load current for each motor 21a. It functions as a tactile sensor means for sensing.
Further, the control unit 30 functions as initial position detection means for detecting the initial position of the gripping object X based on the data transferred from the gripping object detection means 40, and further, the gripping object X with respect to the finger 21. It also functions as a movement detecting means for detecting the relative movement of.

  The gripping object detection means 40 is a single or a plurality of image sensors (for example, CCD, CMOS, etc.). The gripping object detection means 40 images the gripping object X, the hand unit 20, etc. Transfer to the control unit 30.

  In addition, as other examples of this grasping target object detection means 40, the aspect using non-contact sensors, such as an infrared sensor and an ultrasonic sensor, the aspect arrange | positioned in the palm part 22 of the hand part 20, and other parts, It is also possible to do.

Next, a method for controlling the hand robot A configured as described above will be described in detail with reference to the flowchart shown in FIG.
First, the control unit 30 detects the initial position of the gripping target object X and the initial position of the hand unit 20 by the gripping target object detection means 40 (step 1). Then, the hand moving mechanism 10 is operated in accordance with the detected value, and the hand unit 20 is moved until the relative positional relationship that allows the gripping target object X to be gripped by the hand unit 20 is reached (step 2).
The relative positional relationship is obtained in advance by calculation or experiment, and is stored in the storage device of the control unit 30.

In the next step 3, the joints corresponding to the respective motors 21a are bent by energizing the plurality of motors 21a of the respective finger bodies 21 in a predetermined order.
In addition, although it is preferable to operate a plurality or all of the fingers 21, for example, it is possible to adopt a mode in which only one finger 21 is operated. In this case, The grasped object X is grasped between the other non-operating fingers 21.

  About the said order, according to the aspect illustrated to FIG.5 (I)-(III), by energizing the several motor 21a for every joint in each finger 21 in order from a finger base side, this finger 21 Bend the joints in order from the root of the finger.

In step 4, it waits for each motor 21a in the same finger body 21 to be sensed by the tactile sensor means, and if there is sense, the process proceeds to the next step 5.
More specifically, the control unit 30 monitors the load current of the motor 21a for each motor 21a in the same finger 21 with a current sensor, and when the load current has a specific change (for example, the load current is When the predetermined threshold value is exceeded, it is considered that the tactile sensor means has sensed, and the process proceeds to the next step 5. Here, in the state of “when there is a specific change in the load current”, a state in which the joint portion 2 (or 1) of the joint corresponding to the motor 21a is pressed against the outer surface of the grasped object X And a state where the joint is bent to the limit of movement.

  In step 5, every time the tactile sensor means senses in step 4, the motor 21a of the joint corresponding to the sensed tactile sensor means is de-energized and the joint is locked by the one-way power transmission mechanism 21c. Put it in a state.

Steps 3 to 5 will be described in more detail based on the illustrated example. First, the most proximal motor 21a of the finger 21 is driven to rotate the node 1 in the bending direction. When the node 1 abuts on the grasped object X and is detected by the tactile sensor means corresponding to the joint on the root side of the node 1, the motor 21a is deenergized in response to this detection. The joint on the base side of the node portion 1 is brought into a locked state by the one-way power transmission mechanism 21c corresponding to the joint (see FIGS. 5 (I) to (II)).
Next, the node portion 2 is rotated in the bending direction by driving the second motor 21a from the finger base side. When the node 2 comes into contact with the grasped object X and is detected by the tactile sensor means corresponding to the joint between the nodes 1 and 2, the motor 21a is deenergized in response to the detection. The joint between the node parts 1 and 2 is brought into a locked state by the one-way power transmission mechanism 21c corresponding to the joint (see FIGS. 5 (II) to (III)).

After these operations, the control unit 30 determines whether or not all the motors 21a have been de-energized (step 6). If all are de-energized, the process proceeds to the next step 7; Return the process to step 4.
In addition, when all the motors 21a are de-energized, the time when all the joints are locked simultaneously is an extremely short time of less than 1 second.

Next, in step 7, the process proceeds to the next step 8 while energizing a predetermined motor 21 a and bending the joint corresponding to the motor.
Here, the predetermined motor 21a may be a motor at a position determined in advance according to the shape, elasticity, or the like of the grasped object X.
The predetermined motor 21a is not limited to one of the plurality of motors 21a, but may be a part or all of the plurality of motors 21a.

Next, the control unit 30 calculates a gripping force based on the detection value of the tactile sensor means corresponding to the predetermined motor 21a, and waits for the gripping force to become a target gripping force (step 8).
When the gripping force reaches the target gripping force, the control unit 30 deenergizes all the motors 21a including the predetermined motor 21a and locks all the joints (step 9).
In the above step, the gripping operation of the finger 21 until the gripping force becomes the target gripping force is performed quickly and with high accuracy by performing PID control of the motor 21a.

  In the next step 10, it is determined whether or not there is a termination command for terminating the operation of the hand robot A. If there is a termination command, all the processes in the flowchart are terminated. Proceed with the process.

Here, the end command can be, for example, a signal input to the control unit 30 from the outside of the hand robot A, a signal input to the control unit 30 in response to an operation of an end button (not shown), or the like.
As another example of the end command, a signal that is automatically issued on the condition that the elapsed time has reached a predetermined time after the step 9, or a process after step 11 described later is performed a predetermined number of times. It is also possible to use a signal that is automatically issued on the condition.

In the next step 11, the control unit 30 detects the movement (position change) of the gripping object X relative to the hand unit 20 using the gripping object detection means 40.
Here, specifically, the “movement” can be a movement amount (position change amount), a movement speed, or the like of the grasped object X. This “movement” is the position coordinate or posture (angle) of the gripping object X detected by the gripping object detection means 40 after the hand unit 20 grips the gripping object X and locks all the joints in step 9. ) Is calculated by the control unit 30 on the basis of the change.

  In the next step 12, it is determined whether or not the movement has occurred. If the movement has occurred, the process proceeds to step 13, and if not, the process according to the flowchart ends.

In step 13, the target gripping force (see step 8) is corrected so as to increase in accordance with the movement, and the process returns to step 6.
In this correction, for example, when the movement of the grasped object X in the direction of gravity is detected, the target holding force is increased according to the movement amount or the movement speed.
Further, for example, when a posture change (rotation) of the grasped object X is detected, the target holding force is increased according to the rotation amount or the angular velocity.
Further, when the moving direction of the grasped object X is a specific direction with a low possibility of dropping, such as a direction toward the palm 22, for example, the correction is not performed.

  Although the flowchart is omitted, depending on the moving direction or moving angle of the gripping object X based on the detection value of the gripping object detection means 40, the finger body 21 is rotated inward or outward on the rotation axis a, Thereafter, the processing may be returned to Step 6 and the gripping of the gripping object X by the hand unit 20 may be performed again.

Therefore, according to the hand robot A having the above-described configuration, the finger 21 is bent in order from the joint on the root side and is gripped so as to wrap the grip target object X. While preventing a strong stimulus from being applied, a soft and reliable gripping operation can be expected.
In addition, even if the grasped object X once grasped moves from the initial grasping position due to its own weight, vibration, contact with another object, or the like, the finger body 21 does not continue its movement. The gripping object X can be gripped more strongly by operating again.
Moreover, since the motor 21a is de-energized after the gripping object X is gripped by the hand unit 20, the power consumption can be reduced.

Further, unlike the prior art, there is no need to increase the motor torque as it goes to the base side of the finger, so that each finger 21 and the entire hand unit 20 can be reduced in size.
For example, like the finger body 21 ′ illustrated in FIG. 6, a motor M4 having the largest torque is provided at the joint closest to the fingertip, and motors M3. M2 and M1 may be provided, and each of these motors may include a one-way power transmission mechanism 21c.
According to this finger 21 ', the motor M3. After bending M2 and M1, the motor M4 having a relatively large control region can be controlled and operated with high precision, and the control after step 7 can be performed finely.

<Other variations>
In addition, according to the said embodiment, although the elastic part 21e was provided in the frontmost side of the finger body 21, this elastic part 21e is the finger body 21 between the palm part 22 and the finger body 21 most advanced part. What is necessary is just to provide in the part which gripping force acts when grasping | ascertaining the object X, as another example, the aspect provided in the joint between the adjacent node parts 1 and 2, between the node part 2 and the palm part 22 The aspect provided in the joint, the aspect provided in the power transmission path other than the tip portion of the finger body 21, the aspect provided with the elastic portions 21e at a plurality of locations, and the like can be employed.
Furthermore, as another example, it is possible to adopt a mode in which only the mechanism of the finger body 21 and the elasticity of the nodes 1 and 2 are used as the elastic part, and the elastic part 21e made of an elastic material is omitted.

Moreover, according to the said embodiment, as a preferable aspect to hold | grip so that the large holding | grip target object X may be wrapped especially compared with the hand part 20, the several motor 21a in the finger body 21 is sequentially ordered from a finger base side. Although energization is performed, the order can be appropriately changed according to the size and shape of the grasped object X.
For example, as a preferred mode for gripping a gripping object X that is smaller than the hand unit 20 in particular, by energizing the plurality of motors 21a in each finger body 21 in order from the fingertip side to the root side, The joint of each finger 21 is bent in order from the fingertip side to the root of the finger.
As another example, it is possible to adopt a mode in which the plurality of motors 21a are energized in a preset order other than the above.

In the above embodiment, the tactile sensor means detects the reaction force during bending from the load current of the motor 21a. However, as another example of the tactile sensor, the tactile sensor means does not detect the load current of the motor 21a. Instead, it is also possible to measure the load torque of the motor 21a with a separate torque sensor and sense the reaction force during bending.
Furthermore, as another example of the tactile sensor means, a mode using a pressure sensor, a strain gauge, an angle sensor, a tactile sensor, a force sensor, or the like can be employed. For example, each node 1 (or 2) It is possible to adopt a mode in which a known tactile sensor for sensing that the object to be grasped X is pressed is provided on the surface of the finger pad side.

Moreover, according to the said embodiment, although it was set as the structure which detects the movement of the holding | grip target object X with respect to the hand part 20 using the holding | grip target object detection means 40, as another example, the palm part 22 in the hand part 20 or finger | toe It is also possible to detect the abdominal contact pressure with a tactile sensor and recognize the movement of the grasped object X according to the contact pressure distribution.
Further, as another example, a force or moment in a power transmission path such as a connecting portion of the hand unit 20 and the arm 14 or a finger 21 is detected from a torque sensor, a load current value, or the like. It is also possible to recognize the movement of the object X.

  Further, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1, 2: Node part 10: Hand moving mechanism 20: Hand part 21: Finger body 21a: Motor 21b: Speed control mechanism 21c: Unidirectional power transmission mechanism 21d: Bending / extending mechanism 22: Palm part 30: Control part 40: Grasping object Object detection means a, b, c: rotation axis A: hand robot

Claims (6)

Fingers for flexing and extending a plurality of joints, motors provided for each of the joints, power applied to the input unit from the motor side provided for each motor can be transmitted to the output unit, and the output from the output side When a force is applied to the part, a one-way power transmission mechanism that locks the output part, a bending / extension mechanism that flexes and extends the corresponding joint by the power of the output part, and the finger grips the object to be grasped Of a hand robot provided with an elastic portion provided at a portion where a gripping force is applied and a tactile sensor means provided for each joint to sense a reaction force when the joint is bent. A control method,
A first step of bending the joints corresponding to each motor by energizing a plurality of motors of the finger in a predetermined order;
A second step of de-energizing a motor of a joint corresponding to the sensed tactile sensor means every time the tactile sensor means senses, and bringing the joint into a locked state by the one-way power transmission mechanism;
A third step of energizing a predetermined motor to bend a joint corresponding to the motor on condition that all motors are de-energized;
A fourth step in which all the motors including the predetermined motor are de-energized and all the joints are locked on condition that the gripping force based on the detection value of the tactile sensor means becomes a target gripping force; A method for controlling a hand robot, comprising: The finger body has a movable limit when the joints are bent,
In the second step, whenever the tactile sensor means senses a reaction force due to the movable limit or a reaction force when the finger is pressed against the grasped object, the sensed tactile sense 2. The hand robot control method according to claim 1, wherein the joint motor corresponding to the sensor means is de-energized and the joint is locked by the one-way power transmission mechanism. An initial position detecting means for detecting an initial position of a grasped object; and a hand moving mechanism for moving a hand portion provided with a plurality of the fingers.
Prior to the first step, the initial position detecting means recognizes the initial position of the object to be gripped, operates the hand moving mechanism in accordance with the initial position, and moves the hand unit to hold the object to be gripped. The hand robot control method according to claim 1, wherein the hand robot is moved to a grippable position.   In the first step, by energizing a plurality of motors in the finger body in order from the finger base side, the joint of the finger body is bent in order from the finger root side. 4. The method for controlling a hand robot according to any one of 3 above.   4. The method according to claim 1, wherein in the first step, a plurality of motors in the finger body are sequentially energized from the fingertip side to bend the joint of the finger body in order from the fingertip side. A method for controlling a hand robot according to claim 1.   There is provided a movement detecting means for detecting a relative movement of the grasped object with respect to the finger, and after the fourth step, it is determined whether or not the grasped object is moved by the movement detecting means, and there is a movement. 6. The hand robot control method according to claim 1, wherein the target gripping force is corrected so as to increase in accordance with the movement, and the process returns to the third step.

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