Robust operation of tendon-driven robot fingers using force and position-based control laws
First Claim
1. A robotic system comprising:
- a robotic finger driven by a tendon, wherein the robotic finger includes a plurality of joints and a tension sensor positioned in or along the robotic finger;
an actuator connected to the tendon and operable to move the robotic finger, via tensioning of the tendon, with respect to at least one of the joints of the robotic finger; and
a control system providing a two-tier control architecture or hierarchy, including a joint-level controller which forms an upper control loop and an actuator-level controller which forms a lower control loop of the two-tier control architecture or hierarchy, wherein the control system is configured for;
determining whether the tension sensor is functioning properly or otherwise available in the robotic finger to measure a tension value of the tendon;
selectively controlling the robotic finger via a force-based control law or a position-based control law, via the joint-level controller, when the tension sensor is available in the robotic finger; and
selectively controlling the robotic finger via only the position-based control law, solely via the actuator controller, when the tension sensor is not available in the robotic finger to measure the tension value.
5 Assignments
0 Petitions
Accused Products
Abstract
A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.
9 Citations
18 Claims
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1. A robotic system comprising:
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a robotic finger driven by a tendon, wherein the robotic finger includes a plurality of joints and a tension sensor positioned in or along the robotic finger; an actuator connected to the tendon and operable to move the robotic finger, via tensioning of the tendon, with respect to at least one of the joints of the robotic finger; and a control system providing a two-tier control architecture or hierarchy, including a joint-level controller which forms an upper control loop and an actuator-level controller which forms a lower control loop of the two-tier control architecture or hierarchy, wherein the control system is configured for; determining whether the tension sensor is functioning properly or otherwise available in the robotic finger to measure a tension value of the tendon; selectively controlling the robotic finger via a force-based control law or a position-based control law, via the joint-level controller, when the tension sensor is available in the robotic finger; and selectively controlling the robotic finger via only the position-based control law, solely via the actuator controller, when the tension sensor is not available in the robotic finger to measure the tension value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A control system for a robotic finger driven by a tendon and having a plurality of joints, an actuator connected to the tendon that is operable to move the robotic finger via the tendon with respect to at least one of the joints, and a tension sensor positioned in or along the robotic finger, the control system comprising:
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a host machine; and a non-transitory computer-readable medium on which is recorded a control process providing a two-tier control architecture for controlling the finger; wherein the host machine is configured for providing a two-tier control architecture or hierarchy, including an upper control loop and lower control loop of the two-tier control architecture or hierarchy, and is further configured for; executing the control process from the computer-readable medium to thereby determine the availability of a tension sensor in the robotic finger suitable for measuring a tension value, including determining whether the tension sensor is functioning properly or otherwise available to measure a tension value of the tendon, and for selectively controlling the robotic finger; via the upper control loops to selectively apply a force-based control law or a position-based control law when the tension sensor is available to measure the tension value of the tendon; and via only the lower control loop using only the position-based control law when the tension sensor is not available to measure the tension value. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for controlling a tendon-driven robotic finger in a robotic system, wherein the robotic finger is driven by a tendon and has a plurality of joints, and wherein an actuator is connected to the tendon and is operable to move the robotic finger with respect to at least one of the joints via tensioning of the tendon, the method comprising:
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determining the availability of a tension sensor for measuring a tension value of the tendon; and selectively controlling the robotic finger, via a joint-level controller of a control system, using a force-based control law or a position-based control law, when the tension sensor is available to measure the tension value; and selectively controlling the robotic finger, via an actuator-level controller of the control system, using only the position-based control law when the tension sensor is not available to measure the tension value; wherein the joint-level controller and the actuator-level controller form a respective upper level and lower level of a two-tier control architecture or hierarchy. - View Dependent Claims (15, 16, 17, 18)
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Specification