Robot arm apparatus and calibration method

1. A medical arm system, comprising:

an arm unit that comprises a plurality of links, wherein the plurality of links is joined by a plurality of joint units;

an imaging unit configured to capture an image of a surgical field, wherein the imaging unit is attachable to the arm unit; and

a processor circuitry configured to:

acquire internal model information;

update an internal model based on the internal model information; and

drive the medical arm system based on the internal model, wherein

the internal model information comprises first geometric information of the arm unit, second geometric information of a jig attachable to the arm unit, and focus position information of the imaging unit, and

the internal model information is acquired in a state in which the imaging unit is pointed at a specific point on the jig as a reference point in a real space.

2. The medical arm system according to claim 1 , wherein the internal model information includes misalignment information that indicates an amount of misalignment between a field of view of the imaging unit and the reference point in the real space.

3. The medical arm system according to claim 1 , wherein the processor circuitry is further configured to:

acquire a plurality of internal model information in a plurality of states in which the arm unit and the imaging unit are in a plurality of positions and a plurality of orientations; and

update the internal model based on the plurality of internal model information.

4. The medical arm system according to claim 3 , wherein

the processor circuitry is further configured to:

acquire the plurality of internal model information with respect to a plurality of reference points; and

update the internal model based on the plurality of internal model information corresponding to the plurality of reference points.

5. The medical arm system according to claim 3 , wherein the processor circuitry is further configured to:

create a plurality of internal model formulas based on the plurality of internal model information, wherein

each internal model formula of the plurality of internal model formulas represents the internal model, and

each internal model formula of the plurality of internal model formulas includes a discrepancy between a first coordinate system in the internal model and a second coordinate system in the real space; and

update the internal model based on the plurality of internal model formulas.

6. The medical arm system according to claim 1 , wherein the reference point is set as a point in the real space with known coordinates.

7. The medical arm system according to claim 1 , wherein the processor circuitry is further configured to

control a drive operation of a joint unit of the plurality of joint units based on:

a state of the joint unit, and

a first control value for cooperative control of the arm unit, wherein the first control value is based on a state of the arm unit acquired based on a plurality of states of the joint unit.

8. The medical arm system according to claim 7 , wherein the processor circuitry is configured to control the drive operation of the joint unit based on a second control value for whole body cooperative control of the arm unit based on generalized inverse dynamics that utilizes the state of the arm unit acquired based on:

a plurality of detected states of the joint unit, and

a purpose of motion and a constraint condition of the arm unit.

9. The medical system according to claim 8 , wherein

the second control value is computed based on a virtual force that achieves the purpose of motion in an operation space, and

the operation space describes a relationship between a force on the arm unit and an acceleration in the arm unit, and an actual force by which the virtual force drives the joint unit based on the constraint condition.

10. The medical arm system according to claim 7 , wherein

the processor circuitry is further configured to control the drive operation of the joint unit based on a command value, and

a computation of the command value is based on a correction operation on an influence of a disturbance on the first control value.

11. The medical arm system according to claim 10 , wherein the command value is based on a disturbance estimation value that indicates the influence of a disturbance on driving of the joint unit estimated based on a detected state of the joint unit.

12. The medical arm system according to claim 8 , wherein the processor circuitry is configured to:

control the drive operation of the joint unit based on the constraint condition that indicates a certain point in the real space is positioned on an optical axis of the imaging unit, and

control the drive operation of the arm unit based on a pivot operation in which the certain point serves as an apex of the pivot operation in the state in which the imaging unit is pointed at the certain point.

13. The medical arm system according to claim 8 , wherein the processor circuitry is further configured to:

control the drive operation of the joint unit based on the constraint condition that indicates a first point that is locked to a second point, wherein

the first point is on an optical axis of the imaging unit, and

the second point is a certain point in the real space; and

control the drive operation of the arm unit based on a pivot operation centered on the second point in the state in which the imaging unit is pointed at the certain point.

14. The medical arm system according to claim 1 , wherein each joint unit of the plurality of joint units includes a joint state detecting unit that is configured to detect a state of a joint unit of the plurality of joint units, and the joint state detecting unit includes at least one of:

a torque detecting unit configured to detect a generated torque in the joint unit and an external torque applied from an outside to the joint unit, and

a rotational angle detecting unit configured to detect a rotational angle of the joint unit.

15. The medical arm system according to claim 7 , wherein the first control value is a torque in the joint unit.

16. The medical arm system according to claim 1 , wherein the imaging unit is a microscope.

17. A calibration method, comprising:

in a medical arm system comprising an arm unit and an imaging unit attachable to the arm unit, the arm unit comprising a plurality of links joined by at least one joint unit, and the imaging unit configured to capture an image of a surgical field:

acquiring internal model information; and

updating an internal model based on the internal model information, wherein

the internal model is used to drive the medical arm system,

the internal model information is acquired in a state in which the imaging unit pointed at a specific point on a jig attachable to the arm unit as a reference point in a real space, and

the internal model information comprises first geometric information of the arm unit, second geometric information of the jig attachable to the arm unit, and focus position information of the imaging unit.

18. A non-transitory computer-readable medium having stored thereon, computer-executable instructions, which when executed by a computer, cause the computer to execute operations, the operations comprising:

in a medical arm system comprising an arm unit and an imaging unit attachable to the arm unit, the arm unit comprising a plurality of links joined by at least one joint unit, and the imaging unit configured to capture an image of a surgical field:

acquiring internal model information; and

updating an internal model based on the internal model information, wherein

the internal model is used to drive the medical arm system,

the internal model information is acquired in a state in which the imaging unit is pointed at a specific point on a jig attachable to the arm unit as a reference point in a real space, and

the internal model information comprises first geometric information of the arm unit, second geometric information of the jig attachable to the arm unit, and focus position information of the imaging unit.