Analysis of the decoupling control loop for a plant with input dynamics in the ADRC structure

This study addresses the decoupling issue within the Active Disturbance Rejection Control (ADRC) framework, taking into account the existence of additional dynamics in the plant input path. These additional dynamics are not directly incorporated into the observer equations. The paper proposes a compensation strategy that employs a filter to shape the observer’s input signal. The transfer function forms for the structure under analysis, as well as the matching conditions in the input path, have been established. The findings indicate that while the use of an input filter can enhance the stability of the decoupling loop, it may also reduce the disturbance attenuation. The conclusions drawn from analytical studies and numerical simulations are validated by experimental results.