An automatic robot polishing control method for compound surface comprising plane and curved surfaces

Abstract

This paper presents a robotic polishing method for compound surfaces comprising plane and curved surfaces to increase quality and reduce costs, time, and effort compared to manual polishing. The proposed polishing approach is based on smooth trajectory planning, a constant force algorithm, and removal profile depth modeling. To generate a smooth polishing path that increases the stability and accuracy of motion during the polishing operation, a cubic non-uniform rational B-spline interpolation curve is implemented using the harmonic model approach and squad method. An online stiffness and reverse damping force (OSRDF) impedance controller supported by a gravity compensation algorithm is used to achieve a constant polishing force. To evaluate the quality of polishing, the removal depth was determined for plane and curved surfaces before and after polishing. Experimental studies were conducted to polish a manufactured box made of a resin material. The UR robot manipulator was used to validate the proposed method. The results highlighted the constancy of the polishing force owing to the OSRDF impedance controller, with only a small fluctuation that is directly proportional to the value of applied force. The most accurate and uniform removal depth was achieved with an applied force of 20 N. The overall results highlight the capability of the proposed method for polishing compound surfaces to achieve a shiny and smooth surface finish after painting it.