Force Control of SCARA Robot Driven by Stepping Motor

Abstract

In this paper, it is shown that force control of the SCARA robot driven by stepping motors is possible by controlling the torsion angles of joints and the stiffness characteristics of the stepping motor. By means of this control method, the system of force control can be simplified, because the stepping motor does not require feedback control of the position. And it is also shown that the force always acts to the desired direction when time constant of each joint is adjusted rightly. Therefore, force control which does not depend on the orientation of the robot is possible. Moreover, in consideration of the dynamic characteristics of the stepping motor to control without the step-out phenomenon, the condition of the trajectory planning and that of feedback gain are described. As the experimental results, it is shown that the proposed methods are applicable for the force control.