A Synchronous Tracking Algorithm for Positioning Servo System With Double-Loop Control

In some point-to-point control applications, the implementation cost and the complexity of the control strategies are the key factors limiting the advanced improvements in the dynamic performance of motors. This paper develops a compound control strategy based on the micro-brushed DC motor (MBDC) for high-precision applications. The MBDC can be considered as a prospective candidate for fast response and precise motion control applications due to its small size, light weight, high positioning accuracy, simple control, and excellent start-stop performance. The proposed strategy consists of the following components: 1) a double-loop control structure based on position and current loops, which is replaced by a current hysteresis regulation circuit (CHRC), 2) the algorithm combining the characteristics of velocity profile and feedback-feedforward control, which realizes the synchronous trajectory tracking, 3) the optimization of the model-based feedforward controller by incorporating considerations for the effects of zero-order hold and inverter delay. The feasibility of the proposed strategy is verified through MATLAB simulation. The effectiveness of the proposed strategy is further validated through a series of experiments based on an FPGA controller. The experimental results show that the proposed strategy is easy to implement and effectively optimizes the performance on the dynamic response, that the maximum tracking error was reduced from 23.75<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> to 2.7<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> with the addition of the optimized feedforward control.