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A number of industrial robots today have relatively good repeatability, yet, lack good accuracy and stability at high speeds. This paper presents an approach to measuring the positional overshoot of a six-axis revolute robot and a motor controller scheme to improve this problem. Positional accuracy data were collected for various speed ranges to characterize the overshoot phenomenon. This problem, to a great extent, was attributed to the controller design in which a simple positional feedback law was used to drive a stepper motor on each joint of the robot. To compensate for this, a second-order model for the motor and an optimal control law, which comprises position and velocity feedback, are proposed to improve the stability of the motor. A single-axis motion control system was developed to simulate the joint motion of the robot, and to evaluate the control scheme. Simulation results show that significant improvement in overshoot is achieved by the new controller.