Joint-space impedance control for tendon-driven manipulators
First Claim
1. A method for providing torque control of a tendon-driven manipulator, said method comprising:
- calculating by a processer, actuator reference positions or motor commands by projecting a torque error into a tendon position space using a single linear operation;
calculating the torque error using sensed tendon tensions, a reference torque and internal tension; and
limiting minimum and maximum tendon tensions by projecting the torque error into the tendon tension space and then projecting the torque error into a joint space.
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Abstract
A system and method for controlling tendon-driven manipulators that provide a closed-loop control of joint torques or joint impedances without inducing dynamic coupling between joints. The method includes calculating tendon reference positions or motor commands by projecting a torque error into tendon position space using a single linear operation. The method calculates this torque error using sensed tendon tensions and a reference torque and internal tension. The method can be used to control joint impedance by calculating the reference torque based on a joint position error. The method limits minimum and maximum tendon tensions by projecting the torque error into the tendon tension space and then projecting ii back into joint space.
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Citations
20 Claims
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1. A method for providing torque control of a tendon-driven manipulator, said method comprising:
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calculating by a processer, actuator reference positions or motor commands by projecting a torque error into a tendon position space using a single linear operation; calculating the torque error using sensed tendon tensions, a reference torque and internal tension; and limiting minimum and maximum tendon tensions by projecting the torque error into the tendon tension space and then projecting the torque error into a joint space. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for providing torque control of a tendon-driven manipulator, said method comprising:
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calculating by a processor, actuator reference positions or motor commands by projecting a torque error into a tendon position space using a single linear operation; calculating the torque error using sensed tendon tensions, a reference torque and internal tension; limiting minimum and maximum tendon tensions by projecting the torque error into the tendon tension space and then projecting the torque error into a joint space including converting a tendon limiting value from the joint space to the tendon space, limiting the tendon tensions, and converting the tendon tension back from the tendon space to the joint space; providing a proportional-integral controller to control torque and internal tension or joint space impedance; calculating a command actuator position by adding a velocity feedback term and a torque error term to a current actuator position; and calculating a torque error reference using the torque error term by multiplying a joint error by a stiffness constant to realize a positive stiffness. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification