Redundancy Resolution Scheme for Manipulators Subject to Inequality Constraints

The aim of this paper is the development of a redundancy resolution scheme for manipulators able to cope with kinematic constraints. In detail, the structure of the controller is of weighted least norm (WLN) type. The constraints are modeled as unilateral inequalities and can be general scalar functions (linear or nonlinear) of both the joint position and the joint velocity variables. In this work, a general procedure is proposed in order to include constraints of different types, namely functions of joint position or velocity only, functions of both joint position and velocity with a time dependent or time independent threshold. Simulations are performed in Matlab-Simulink environment and two tests are performed: the first employs a single 7-DOF arm, while in the second a dual-arm system composed of two 7-DOF manipulators is used. Results show that the proposed redundancy resolution scheme is capable of satisfying complex inequality constraints where other known methods fail.