Force and Acceleration Sensor Fusion for Compliant Robot Motion Control

In this work, we present implementation and experiment of the theory of dynamic force sensing for robotic manipulators, which uses a sensor fusion technique in order to extract the contact force exerted by the end-effector of the manipulator from those measured by a wrist force sensor, which are corrupted by the inertial forces on the end-effector. We propose a new control strategy based on multisensor fusion with three different sensors— that is, encoders mounted at each joint of the robot with six degrees of freedom, a wrist force sensor and an accelerometer— whose goal is to obtain a suitable contact force estimator for the three Cartesian axes. This new observer contributes to overcome many of the difficulties of uncertain world models and unknown environments, which limit the domain of application of currents robots used without external sensory feedback. An impedance control scheme was proposed to verify the improvement. The experiments were carried out on an ABB industrial robot with open control system architecture.

I. Introduction

It has been long recognized that multisensor-based control is an important problem in robotics. As a robotic manipulator is expected to accomplish more and more complex tasks, such as assembly and task planning in a manufacturing workcell, the need to take advantage of multiple sensors in controlling a system becomes increasingly important [1].