Application of a PID Controller using MRAC Techniques for Control of the DC Electromotor Drive

In DC motor drives, device aging and environmental factors can degrade the performance of the control system and make it difficult to redesign controller parameters in real time. In this paper, an algorithm that combines PID control scheme and model reference adaptive control (MRAC) to autotune the controller parameters in real time when system performances change is proposed and applied to control of the DC electromotor drive. The algorithm modifies the traditional PID control scheme by replacing the error between the reference and the system output with the direct system output in the derivative part. Compared to the traditional MRAC approach, the algorithm is normalized so that a reference model can be easily generated given bandwidth requirement. To be practical for implementation, the algorithm also simplifies the transfer function of the speed open-loop as an integrator by adding a current inner loop. The results of simulation on a two-loop servo control system show that the adjusted controller parameters meet the system design very well. The algorithm was implemented on a test platform and the performance of the system was evaluated with a dynamic signal analyzer. The effectiveness of the proposed method is shown through the experimental results.