Abstract
The timing belts are widely used for torque transmission in many inductrial applications including the industrial robots. In such system, the vibration is often generated because of the elasticity of the belts. This vibration makes it difficultt to achieve quick responses and smooth motion control. In this paper, the position control system of a horisontal robot arm with flexible timing belts is proposed. The mechanical system of the robot is modeled as a two-mass system, which consists of the motor side mass, the arm side mass and the spring element due to elasticity of the belts. The position control without vibration is based on the state feedback of the motor position, the motor speed and the torsional torque caused by the flexible belts, where the motor speed and the torsional torque are estimated by the least-order observer because the detectable information is only the motor position from the rotory-encorder. The arm side inertia varies according to the arm position, as a result the mechanical system is nonlinear. Therefore, the feedback gains are adjusted according to the arm position in the proposed system. The effectiveness of the proposed system is verified by the experimental results.
