Real-Time Manipulation of a Hybrid Serial-and-Parallel-Driven Redundant Industrial Manipulator

Abstract

The real-time implementation of path planning, trajectory generation, and servo control for manipulation of the prototype UPSarm are presented in this paper. The prototype UPSarm, which is primarily designed for studying the feasibility of loading packages inside a trailer, is a ten degree-of-freedom hybrid serial-and-parallel-driven redundant robot manipulator. The direct, forward, inverse, and indirect kinematic solutions of the UPSarm using three coordinate spaces: actuator space, effective joint space, and world Cartesian coordinate space are derived for real-time path planning, trajectory generation, and control. The manipulation of the UPSarm is based upon a general-purpose path planner and trajectory generator. Provided with appropriate kinematics modules and sufficient computational power, this path planner and trajectory generator can be used for real-time motion control of any degree-of-freedom hybrid serial-and-parallel-driven electromechanical devices. A VMEbus-based distributed computing system has been implemented for real-time motion control of the UPSarm. A PID-based feedforward servo control scheme is used in our servo controller. The motion examples of the UPSarm programmed in our robot language will show the practical manipulation of hybrid serial-and-parallel-driven redundant kinematic chains.