Experiments with Force Control of Redundant Robots in Unstructured Environment Using Minimal Null-space Formulation

Abstract

The paper describes the implementation of the force control for redundant robots in an unstructured environment. We assume that the obstacles are not known in advance. Hence, the robot arm has to be compliant with the environment while tracking the desired position and force at the end effector. Using the minimal null space approach the appropriate impedance controller, which decouples the end effector and the null space spaces was derived. The control algorithm enables the selection of dynamic characteristics in both subspaces independently.The proposed method was verified with the simulation and with experiments on a 4 D.O.F planar redundant robot.