Sliding Mode Control with PID Tuning Technique: An Application to a DC Servo Motor Position Tracking Control

Problem statement: In this study, a combination of a classical Sliding Mode Control (SMC) and a PID tuning technique with low-pass filter is developed for a position tracking control of a DC servo motor. Approach: The DC servo motor will be used to adjust the throttle angle of the gasoline engine in our laboratory. To control the engine speed to be accurate, the servo motor position has to be controlled precisely. Results: Uncertainty and nonlinearity of the servo motor system can be surmounted by the sliding mode control while the system response can be fine adjusted via the PID gain tuning. A low-pass filter has been incorporated also in order to eliminate and limit amplification of noise due to differentiation in the PID algorithm. The stability of the control system is guaranteed by the Lyapunov stability theorem. The experimental results shown that, the proposed technique has good tracking performance compares to a PIDSMC and a conventional PID technique even without actuator model. Conclusion/Recommendations: However, the performance strongly depends on the specified control gain in PID portion and sliding function. Therefore, any self tuning control gain techniques should be developed further.