Hand, handling robot, control device, method for controlling hand, and storage medium

1 . A hand, comprising:

a gripper configured to grip an object;

a driver configured to drive the gripper; and

a controller configured to

generate a gripping plan using an image of the object, the gripping plan including a grip position and a grip posture,

after generating the gripping plan that includes the grip position and the grip posture, cause the driver to drive the gripper to the grip position and the grip posture,

after generating the gripping plan that includes the grip position and the grip posture, estimate a stability when gripping the object, the stability being estimated based on contact information of the gripper for the object and characteristic information including at least one of a size or a weight of the object, the contact information being generated at the grip position and in the grip posture,

cause the driver to perform a first motion to increase the stability in a case where the stability is estimated and does not exceed a first threshold, and

during the first motion, determine that a gripping motion is completed in a case where the stability exceeds the first threshold.

2 . The hand according to claim 1 , wherein

in a case where the stability is not estimated, the controller causes the driver to perform a second motion, and

the second motion is preset.

3 . The hand according to claim 2 , wherein

in a case where the stability is estimated during the second motion, the controller causes the driver to end the second motion and perform the first motion.

4 . The hand according to claim 1 , wherein

in the estimation of the stability, the controller is configured to:

estimate a grip state based on the contact information and the grip position; and

calculate the stability based on the grip state.

5 . The hand according to claim 1 , wherein

in a case where the stability is estimated and exceeds the first threshold before performing the first motion, the first motion is not performed.

6 . The hand according to claim 1 , wherein

the gripper includes a suction mechanism configured to suction-grip the object.

7 . The hand according to claim 6 , wherein

the gripper includes a pad contacting the object, and

the controller is configured to acquire the contact information based on a detected value of a pressure inside the pad.

8 . The hand according to claim 6 , wherein

the driver includes a rotation axis changing a posture of the gripper, and

in the first motion, the controller is configured to:

calculate a rotation angle of the rotation axis based on the stability, and

rotate the rotation axis not less than the rotation angle to increase the stability.

9 . The hand according to claim 1 , wherein

the gripper includes a pinching mechanism configured to pinch the object.

10 . The hand according to claim 9 , wherein

the pinching mechanism includes a plurality of supporters,

the pinching mechanism is configured to pinch the object by using the plurality of supporters,

the driver includes a motor for driving the plurality of supporters, and

the controller is configured to acquire the contact information based on a current value of the motor.

11 . The hand according to claim 10 , wherein

a distance between the plurality of supporters is changed by an operation of the motor, and

in the first motion, the controller is configured to:

calculate a rotation angle of the motor based on the stability; and

rotate the motor not less than the rotation angle to increase the stability.

12 . The hand according to claim 1 , wherein

the characteristic information further includes a center of gravity of the object.

13 . The hand according to claim 1 , wherein

the stability is expressed as a ratio of a grip force when the object is gripped to a necessary grip force, and

the necessary grip force is necessary to grip and transfer the object.

14 . A handling robot, comprising:

the hand according to claim 1 ; and

an arm to which the hand is mounted,

the arm being configured to change a position or a posture of the hand.

15 . The robot according to claim 14 , wherein

the position and the posture of the hand are changed by the arm to increase the stability in the first motion.

16 . A handling robot, comprising:

the hand according to claim 1 ; and

an arm to which the hand is mounted,

in a case where the hand contacts the object at the grip position, the hand or the arm being moved to increase a grip force of the object by the hand, and

in a case where the hand does not contact the object at the grip position, the hand being moved according to a motion pattern,

the motion pattern being preset.

17 . The robot according to claim 16 , wherein

in a case where the hand contacts the object in the motion pattern, the motion pattern is stopped, and the hand or the arm is moved to increase the grip force of the object by the hand.

18 . A control device of a hand, the hand including:

a gripper configured to grip an object; and

a driver configured to drive the gripper, the control device comprising: circuitry configured to

generate a gripping plan using an image of the object, the gripping plan including a grip position and a grip posture,

after generating the gripping plan that includes the grip position and the grip posture, cause the driver to drive the gripper to the grip position and the grip posture,

after generating the gripping plan that includes the grip position and the grip posture, estimate a stability when gripping the object, the stability being estimated based on contact information of the hand for the object and characteristic information including at least one of a size or a weight of the object, the contact information being generated at the grip position and the grip posture,

cause the driver to perform a first motion to increase the stability in a case where the stability is estimated and does not exceed a first threshold, and

during the first motion, determine that a gripping motion is completed in a case where the stability exceeds the first threshold.

19 . A method for controlling a hand, the hand including:

a gripper configured to grip an object; and

a driver configured to drive the gripper, the method comprising:

generating a gripping plan using an image of the object, the gripping plan including a grip position and a grip posture;

after generating the gripping plan that includes the grip position and the grip posture, causing the driver to drive the gripper to the grip position and the grip posture;

after generating the gripping plan that includes the grip position and the grip posture, estimating a stability when gripping the object, the stability being estimated based on contact information of the gripper for the object and characteristic information including at least one of a size or a weight of the object, the contact information being generated at the grip position and the grip posture;

causing the driver to perform a first motion to increase the stability in a case where the stability is estimated and the stability does not exceed a first threshold; and

during the first motion, determining that a gripping motion is completed in a case where the stability exceeds the first threshold.

20 . A non-transitory computer-readable storage medium in which a program is stored,

the program causing a computer to execute the method according to claim 19 .

21 . The hand according to claim 1 , wherein

in a case where the stability is not more than the first threshold after completion of the first motion, the controller is configured to repeat a process including estimating the stability and cause the driver to perform the first motion until the stability exceeds the first threshold.

22 . The hand according to claim 2 , wherein

in a case where the stability is not estimated while the driver is performing the second motion, the controller is configured to return processing to estimating the stability based on newly generated contact information.

23 . The control method according to claim 19 , further comprising, in a case where the stability is not more than the first threshold after completion of the first motion, repeating a process including estimating the stability and causing the driver to perform the first motion until the stability exceeds the first threshold.

24 . The control method according to claim 19 , further comprising:

in a case where the stability is not estimated, causing the driver to perform a second motion that is a preset motion pattern; and

in a case where the stability is not estimated while the driver is performing the second motion, returning to estimating the stability based on newly generated contact information.