Harry H. Cheng, Jason J. Lee, and Rajan Penkar
This paper presents kinematic analysis of the prototype UPSarm which is designed for studying the feasibility of loading packages inside a flatbed trailer. The UPSarm is a hybrid serial-and-parallel-driven redundant robot manipulator with ten degrees of freedom. The shoulder subsystem of the UPSarm uses a closed-loop kinematic chain whereas the wrist subsystem employs a parallel-driven mechanism so that the manipulator can carry a heavy load. The telescopic motion provides the UPSarm with a large workspace, which is achieved by operating three redundant prismatic joints of the arm. For design, analysis, and real-time control of hybrid serial-and-parallel-driven robot manipulators, three coordinate spaces: the world Cartesian coordinate space, effective joint space, and actuator space are introduced. The effective joint space of the UPSarm forms a ten degrees-of-freedom serial open kinematic chain. The forward and inverse kinematic analysis determines the relation between the world Cartesian coordinate space and effective joint space of the UPSarm. The relation between the effective joint space and actuator space is given by direct and indirect kinematic formulations. An iterative numerical Newton-Raphson method has been used to solve the wrist direct kinematic solutions. The formulations of kinematic solutions derived in this paper have been programmed in SIL language for design and analysis, and in C language for real-time control of the arm.