Method and apparatus for controlling a haptic device

• US 20070296366A1
• Filed: 05/18/2007
• Published: 12/27/2007
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Original Assignee: MAKO Surgical Corporation (Stryker Corporation)
• Inventors: Kang, Hyosig, Moses, Dennis, Quaid, Arthur
• Granted Patent: US 7,683,565 B2
• Time in Patent Office: Days
• US Class Current: 318/568.16
• CPC Class Codes: B25J 13/025 comprising haptic means
• CPC Class Codes: B25J 9/1638 compensation for arm bending/inertia, pay load weight/inertia
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user

Abstract

A method and apparatus for controlling a haptic device. In one embodiment, the haptic device includes an actuator; an actuator sensor, producing an actuator signal indicative of the actuator velocity; a load; a load output sensor producing a load output signal indicative of the load position; and a controller in electrical communication with the load output sensor, actuator sensor and actuator. The controller controls the actuator in response to the actuator signal and the load output signal to provide a haptic response to a user. In one embodiment, the method for controlling an actuator of a haptic device includes the steps of producing an actuator signal indicative of the velocity of an actuator; producing a position signal indicative of the position of a load; and controlling the actuator in response to the actuator signal and the load output position signal to produce a haptic response to a user.

Claims

1. A haptic device comprising:

an actuator;

an actuator sensor in communication with the actuator, the actuator sensor producing an actuator signal indicative of an actuator velocity;

a load;

a load output sensor in communication with the load, the load output sensor producing a load output signal indicative of a load position; and

a controller in electrical communication with the load output sensor, the actuator sensor and the actuator, the controller controlling the actuator in response to the actuator signal and the load output signal to provide a haptic response to a user.

2. The haptic device of claim 1 further comprising a cable drive transmission in communication with the actuator and the load.

3. The haptic device of claim 1 wherein the controller determines a gravity compensation torque and a Cartesian endpoint position in response to the load output signal.

4. The haptic device of claim 1 wherein the controller controls the actuator by computing an endpoint velocity by filtering the actuator signal to form a filtered actuator velocity and multiplying the filtered actuator velocity by a Jacobian.

5. The haptic device of claim 4 wherein the controller computes a damping force by subtracting a reference velocity from the endpoint velocity to form an endpoint velocity difference and multiplying the endpoint velocity difference by a damping gain.

6. The haptic device of claim 5 wherein the controller computes a desired haptic force in response to the damping force.

7. The haptic device of claim 1 wherein the output sensors are selected from the group comprising optical encoders, electric encoders, magnetic encoders, and potentiometers.

8. A method for controlling an actuator of a haptic device comprising the steps of:

producing an actuator signal indicative of a velocity of an actuator;

producing a load position signal indicative of a position of a load; and

controlling the actuator in response to the actuator signal and the load position signal to produce a haptic response to a user.

9. The method of claim 8 further comprising the step of determining a gravity compensation torque and a Cartesian endpoint position in response to the load position signal.

10. The method of claim 8 wherein controlling the actuator comprises the step of computing an endpoint velocity by filtering the actuator signal to form a filtered actuator velocity and multiplying the filtered actuator velocity by a Jacobian.

11. The method of claim 10 further comprising computing a damping force by subtracting a reference velocity from the endpoint velocity to form an endpoint velocity difference and multiplying the endpoint velocity difference by a damping gain.

12. The method of claim 11 further comprising computing a desired haptic force in response to the damping force.

13. A haptic device comprising:

a motor;

a motor sensor in communication with the motor, the motor sensor producing a motor signal indicative of a motor velocity;

a joint;

a joint sensor in communication with the joint, the joint sensor producing a joint position signal indicative of a joint position; and

a controller in electrical communication with the joint sensor, the motor sensor and the motor, the controller controlling the motor in response to the motor signal and the joint position signal to provide a haptic response to a user.

14. A haptic device comprising:

a transmission having an input side and an output side;

an actuator in communication with the input side;

an actuator sensor in communication with the actuator, the actuator sensor producing an actuator signal indicative of an actuator velocity;

a position sensor in communication with the output side, the position sensor producing a position signal indicative of a position of the output side; and

a controller in electrical communication with the position sensor, the actuator sensor and the actuator, the controller controlling the actuator in response to the actuator signal and the position signal to provide a haptic response to a user.