Optimal Zero Placement for PI and PD Control of DC Motors in Medical Applications

Abstract

In medical devices, DC motors are crucial components due to their high efficiency and high starting torque, which effectively address sudden load increases. This study focuses on improving the inherent performance of the system. The proposed approach utilizes PI control for motor speed and PD control for motor angle to optimize system performance. Gain selection is central to this process, ensuring the system maintains robustness while improving response time and minimizing overshoot. The primary task of this research is to select appropriate zero points and gains to achieve optimal performance. Using the root locus method and Matlab, gains for rapid response were identified for a 100mHz DC motor under PI and PD control. Zero points of -11 and -12 were found for high stability requirements and general demands, respectively, offering reduced overshoot and shorter response times. The resulting circuit was constructed based on these values, yielding ideal waveforms and verifying the feasibility of the proposed results. On this basis, further refinement in zero-point selection and optimization of the underlying control system can be pursued.