Design and implementation of a redundantly actuated reconfigurable planar parallel manipulator
Date
2003
Authors
Fisher, Ryan
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Abstract
This work presents the design and implementation of the Reconfigurable Planar Parallel Manipulator (RPPM). The RPPM was designed to act as a testbed manipulator for theories on redundant actuation in parallel manipulators. The RPPM is capable of forming three planar mechanism types, a 3-DOF ( degree of freedom) 8-Bar mechanism, a 3-DOF 6-Bar mechanism, and a 2-DOF 5-Bar Mechanism. The reconfigurable device is designed to allow multiple actuation configurations. Implementation of the non-redundantly actuated RPPM is done with PID control. Hybrid position/force control is used to implement redundantly-actuated configurations. The kinematics of the RPPM is formulated with screw coordinates representing the joints, and by using associated-reciprocal screw coordinates to represent the forces that each joint can apply to the platform. When redundantly actuated, there are an infinite number of solutions for the joint torques required to supply an output force of the end effector. A concept of force scaling is introduced to allow force capability optimization.