Task-oriented configuration design for reconfigurable parallel manipulator systems

A reconfigurable parallel manipulator system consists of an inventory of standard interchangeable actuator modules, passive joint modules and customizable links and connectors. Owing to the interchangeability and modularity, a parallel manipulator constructed in this manner can have different structures and degrees of freedom (DOF). This article presents a two-stage design methodology, from structure determination to parameter optimization, for determining task-specific optimal configurations of reconfigurable parallel manipulators. In the structure determination stage, a reconfigurable robot assembly database containing the possible parallel manipulator assemblies is established based on enumeration. A TaskToRobot Map is proposed to map the given task description to a suitable manipulator configuration in the database according to the DOFs of the required task. In the parameter optimization stage, design parameters of the selected manipulator structure, such as link lengths, dimensions of the connectors and actuation schemes are identified. As these parameters contain continuous and discrete variables, synthesis of the manipulator parameters is formulated based on a Simplex optimization method. This design methodology is demonstrated effectively in the selection of a reconfigurable parallel manipulator system for a light machining operation.