Performance Evaluation of Redundant Parallel Manipulators Assimilating Motion/Force Transmissibility

Abstract

Performance evaluation is one of the most important issues in the field of parallel kinematic manipulators (PKMs). As a very important class of PKMs, the redundant PKMs have been studied intensively. However, the performance evaluation of this type of PKMs is still unresolved and a challenging endeavor. In this paper, indices that assimilate motion/force transmissibility are proposed to evaluate the performance of redundant PKMs. To illustrate the application of these indices, three PKMs with different kinds of redundancies are taken as examples, and performance atlases are plotted based on the definitions of the indices. Transmissibility comparisons between redundant PKMs and the corresponding non-redundant ones are carried out. To determine the inverse solutions of the PKMs with kinematic redundancy, an optimization strategy is presented, and the rationality of this method is demonstrated. The indices introduced here can be applied to the performance evaluation of redundant parallel manipulators.

Power manipulability analysis of redundantly actuated parallel kinematic manipulators with different types of actuators

“…In this context, actuation redundancy has been used to avoid singularities and to enlarge the reachable workspace of parallel manipulators [19]. Furthermore, end-effector forces can be homogenized over the workspace due to improved force transmission capabilities, enabling the application of energy-efficient actuators with less inertia [20]. In addition, control methods have been developed in terms of backlash avoidance [21] and to improve the manipulator's operational stiffness [22].…”

Design methodology for translational parallel manipulators exhibiting actuation redundancy

“…Comprehensive overviews of the (current) state of the art and application examples of redundant configurations can also be found in the literature. 4,7,10,[12][13][14] This study analyzes the development of a translational PM with additional actuated chains, according to redundancy in parallelism. With actuation redundancy, singularities can be avoided, possibly leading to a higher volume of the reachable workspace.…”

A Comparison Study on Motion/Force Transmissibility of Two Typical 3-DOF Parallel Manipulators: The Sprint Z3 and A3 Tool Heads

“…A wealth of research has been published on six-degree-of-freedom (DOF) Stewart-like parallel manipulators, and researchers have come to realize their limitations due to complex direct kinematics, unsatisfactory workspace, and poor orientation capability [3]. However, it is possible for so-called defective parallel manipulators with fewer than six DOFs to overcome these disadvantages while retaining the advantages of parallel manipulators [4]. A significant amount of research has recently been devoted to lowmobility parallel manipulators.…”