PD control is widely used in the control of industrial production process, and it is also one of the control strategies with the simplest structure. It focuses on the steady-state performance of the control system, but there is not enough attention paid on the dynamic performance (including the overshoot and the convergence speed, etc.) of the system. Therefore, if the response speed is improved in the traditional PD control, the overshoot would increase and the oscillation response would be intensified. If a small overshoot is wanted, the response speed might be slow down. It seemes that the response speed and overshoot to be parameters of contradictory performance and it is difficult to improve response speed and reduce overshoot by using traditional PD control alone. The prescribed performance control means that the tracking error should converge to a predefined small residual set, with convergence rate no less than a prespecified value. The combined PD control with the prescribed performance control to design the manipulator motion controller using simple PD control structure and the prescribed performance function based on error transform of logarithmic form. The steady-state error can be preset in the design process of the controller, while the control error of traditional ID controller can only be gradually reduced after multiple parameters setting and debugging. Therefore, the design process of the control algorithm proposed was simple and convenient, with more accurate control precision and faster response speed. At the same time, the control algorithm can control the overshoot within a reasonable range. By the analysis of modeling and simulation of spatial three joints manipulator, the results showed that the prescribed performance PD control has the advantage of 40% faster response and 10% less overshoot comparing with the traditional PD control. By the prototype experimental analysis of the 4D of Dobot manipulator, the results showed that the prescribed performance PD control has the advantage of 20% faster response and 5% less overshoot comparing with the traditional PD control, which makes it obvious for the improvement of the dynamic response performance of the control system.
