An Extended Approach to Estimating Closeness to Singularity in Parallel Manipulators based on Actuating Efforts Values

Abstract

In this paper, the problem of calculating maximal actuation effort in a parallel manipulator is discussed. The actuation efforts increase sharply near the singularities and thus affect the size of the effective working area of the manipulator, which is a significant issue in parallel mechanisms. The presented approach based on the inverse Jacobian matrix and its derivative and considers the link masses and inertia forces and allows finding the worst direction of the end effector velocity and acceleration vectors at any workspace point, which maximizes the actuation effort. This approach thus enables to calculate the size of the effective working area of the manipulator and estimate the necessary characteristics of the drives. A planar five-bar parallel mechanism is presented as an example to illustrate the approach.