Control device, control method, and control system

1. A control device comprising:

a control unit configured to

compare a first external force detected by a force sensor provided in a first portion of a control target and a second external force estimated on a basis of a torque detected by a torque sensor provided in a movable portion of the control target, the movable portion enabling the force sensor to be movable and being different than the first portion of the control target,

correct a torque command value on a basis of a result of the comparison to control an operation of the control target, and

adjust a gain on a basis of a difference between the first external force and the second external force extracted by the comparison and apply the gain to the torque command value to control switching between a first mode where the control target operates based on the first external force detected by the force sensor and the torque detected by the torque sensor and a second mode where the control target operates based on only the first external force detected by the force sensor,

wherein the control unit is implemented via at least one processor.

2. The control device according to claim 1 , wherein

the control unit is further configured to switch between the first mode and the second mode according to an application state of a third external force applied to the control target on the basis of the difference.

3. The control device according to claim 2 , wherein

the control unit is further configured to set the first mode when the application state is in a state where the third external force being expected is applied to the control target.

4. The control device according to claim 3 , wherein

the control unit is further configured to set the first mode by adjusting the gain so as to approach a first value.

5. The control device according to claim 2 , wherein

the control unit is further configured to set the second mode when the application state is a state where the third external force being unexpected is applied to the control target.

6. The control device according to claim 5 , wherein

the control unit is further configured to set the second mode by adjusting the gain so as to approach a second value.

7. The control device according to claim 1 , wherein

the control unit is further configured to continuously switch between the first mode and the second mode by continuously changing the gain.

8. The control device according to claim 7 , wherein

the control unit is further configured to continuously change the gain when the difference is a value within a predetermined range.

9. The control device according to claim 1 , wherein

the control unit is further configured to discontinuously switch between the first mode and the second mode by discontinuously changing the gain.

10. The control device according to claim 9 , wherein

the control unit is further configured to change the gain in a step shape depending on whether the difference is equal to or larger than a predetermined threshold.

11. The control device according to claim 1 , wherein

the control unit is further configured to correct the torque command value on a basis of a value obtained by multiplying an estimated torque estimated on a basis of the torque and an attitude of the control target by the gain.

12. The control device according to claim 11 , wherein

the control unit is further configured to estimate the estimated torque by subtracting an external torque which is a torque generated due to only an operation of the control target from the torque.

13. The control device according to claim 12 , wherein

the control unit is further configured to calculate the external torque by performing inverse kinetics calculation on a basis of a joint angle of the control target.

14. A control method executed by a processor, comprising:

comparing a first external force detected by a force sensor provided in a first portion of a control target and a second external force estimated on a basis of a torque detected by a torque sensor provided in a movable portion of the control target, the movable portion enabling the force sensor to be movable and being different than the first portion of the control target;

correcting a torque command value on a basis of a comparison result to control an operation of the control target; and

adjusting a gain on a basis of a difference between the first external force and the second external force extracted by the comparison and applying the gain to the torque command value to control switching between a first mode where the control target operates based on the first external force detected by the force sensor and the torque detected by the torque sensor and a second mode where the control target operates based on only the first external force detected by the force sensor.

15. A control system comprising:

an arm device including a movable portion having an actuator, an arm portion in which a plurality of links are connected by the movable portion, a torque sensor provided in the movable portion and configured to detect a torque applied to the movable portion, and a force sensor provided in a tip end of the arm portion and configured to detect a first external force applied to the tip end of the arm portion, the tip end of the arm portion being different than the movable portion; and

a control device including a control unit configured to

compare the first external force and a second external force estimated on a basis of the torque,

correct a torque command value on a basis of a comparison result to control an operation of the arm device, and

adjust a gain on a basis of a difference between the first external force and the second external force extracted by the comparison and apply the gain to the torque command value to control switching between a first mode where the arm device operates based on the first external force detected by the force sensor and the torque detected by the torque sensor and a second mode where the arm device operates based on only the first external force detected by the force sensor,

wherein the control unit is implemented via at least one processor.