Masters Thesis

Trajectory Planning Using Higher Order Motion Specifications

This thesis builds on a recently developed Failure Recovery Synthesis (FRS) technique for robotic manipulators, which is mounted on a movable platform to achieve an originally specified task after an arm joint failure. The FRS locks in place the failed arm joint and determines a new position for the base of the arm and a new grasping location for the end-effector. This work aims towards improving the trajectory planning technique of the FRS in order to generate optimal reaching motions in case of an arm joint failure. Aiming towards improving the robotic trajectory planning technique in the FRS, the work adopts previous results from experimental observations on human elbow constrained reaching movements. The assumption that the end-effector of an elbow locked anthropomorphic robotic manipulator is in contact with a specific surface during the entire movement allows us to describe the contact conditions by using higher order kinematic constraints such as velocities, accelerations, and jerks. By adopting contact specifications at initial and final task locations, kinematic synthesis and path planning techniques enable us to generate an entire end-effector trajectory connecting the two locations. The proposed method was validated by comparing its outcome to an actual human elbow-constrained reaching motion profile. The results show a smooth trajectory that closely follows the human hand path.


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