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AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsAbhinandan Jain, Guillermo Rodriguez
Estimating the term…
The invention controls an under-actuated robot manipulator by first obtaining predetermined active joint accelerations of the active joints and the passive joint friction forces of the passive joints, then computing articulated body quantities for each of the joints from the current positions of the links, and finally computing from the articulated body quantities and from the active joint accelerations and the passive joint forces, active joint forces of the active joints. Ultimately, the invention transmits servo commands corresponding to the active joint forces thus computed to respective ones of the joint servos. The computation of the active joint forces is accomplished using a recursive dynamics algorithm. In this computation, an inward recursion is first carried out for each link beginning with the outermost link in order to compute the residual link force of each link from the active joint acceleration if the corresponding joint is active or from the known passive joint force if the corresponding joint is passive. Then, an outward recursion is carried out for each link beginning with the innermost link in which the active joint force is computed from the residual force if the corresponding joint is active or the passive joint acceleration is computed from the residual link force if the corresponding joint is passive.
A method of controlling a robot manipulator which is under-actuated having plural links connected at respective joints therebetween whereby each link is associated with a respective joint, some of said joints being active and having their movements controlled by respective joint servos, remaining ones of said joints being passive and not having their movements controlled by respective joint servos whereby said passive joints are generally freely moveable, an innermost one of said links comprising a relatively stationary base and an outermost one of said links comprising a moveable tip link, said method comprising the steps of:
A method of controlling a robot manipulator which is redundant and under-actuated having at least seven degrees of freedom, whereby equations of motion of said robot manipulator have a redundancy, said robot manipulator comprising plural links connected at respective movable joints therebetween whereby each link is associated with a respective joint, some of said joints being active and having their movements controlled by respective joint servos, remaining ones of said joints being passive and not having their movements controlled by respective joint servos whereby said passive joints are generally freely moveable, an innermost one of said links comprising a relatively stationary base and an outermost one of said links comprising a moveable tip link, said method comprising the steps of:
Apparatus for controlling an under-actuated robot manipulator having plural links connected at respective movable joints therebetween whereby each link is associated with a respective joint, some of said joints being active and having their movements controlled by respective joint servos, remaining ones of said joints being passive and not having their movements controlled by respective joint servos whereby said passive joints are generally freely moveable, an innermost one of said links comprising a relatively stationary base and an outermost one of said links comprising a moveable tip link, said apparatus comprising:
Apparatus for controlling a robot manipulator which is redundant and under-actuated having at least seven degrees of freedom, whereby equations of motion of said under-actuated robot manipulator have a redundancy, said robot manipulator comprising plural links connected at respective movable joints therebetween whereby each link is associated with a respective joint, some of said joints being active and having their movements controlled by respective joint servos, remaining ones of said joints being passive and not having their movements controlled by respective joint servos whereby said passive joints are generally freely moveable, an innermost one of said links comprising a relatively stationary base and an outermost one of said links comprising a moveable tip link, said apparatus comprising:
A method of controlling an under-actuated robot manipulator comprising active joints associated with active links and passive joints associated with passive links, including an outermost one of said links and an innermost one of said links, said method comprising the steps of:
Dependencies are inferred from the claim text.