Adaptive IMC for variable parameter systems with large dead-times

Lianhua Hu^{1, 2}, Xinping Li², Wei Tang¹

¹School of Shaanxi University of Science & Technology, Xi’an City, Shaanxi Province, China, 710021

²Shaanxi Key Laboratory on Paper Technology and Specialty Papers, Xi’an City, Shaanxi Province, China 710021

Dead-time variation can cause object mismatches in traditional internal model control (IMC) systems and may result in a significant overshoot. The adjustment time may increase due to this variation and sometimes even causes oscillation instability. An adaptive IMC method is proposed in this paper to solve the problem of variable parameters in the control process. The adaptive law is designed to optimize local parameters relative to the output error of both the plant and model, ensuring that the model approximates the real plant. The control structure adopts IMC and simulation results show that this type of control structure exhibits some promising characteristics, such as high accuracy, robustness and disturbance rejection. This model is therefore suitable for systems with large dead-time varying parameters.