On the control of the liquid pouring process using cooperative manipulators

Abstract

A robotic system for a liquid pouring application is presented. The robotic system comprises two cooperative manipulators. A simplified model of the robotically controlled pouring process is derived, considering that the liquid's motion is approximated by a pendulum type model. A control scheme is proposed, which achieves positioning of the tank, force control and liquid sloshing suppression. The forces space is decomposed into the moving forces, which are responsible for the motion of the tank and the controllable forces, which may be controlled through the proposed control law. The control scheme comprises a nonlinear inverse dynamic controller, which is designed ignoring liquid sloshing, and a multivariable PID controller, which is used to improve the closed-loop performance with respect to steady state positioning errors and sloshing suppression.