Date of Award


Degree Type



Electrical and Computer Engineering

First Advisor

Dong, Lili

Subject Headings

Motion control devices, Torsion, Automatic control, Observers (Control theory), Motion control, torsional plant, state observer, PD controller


The hardware implementation of an active disturbance rejection controller (ADRC) is presented in the thesis for a mechanical torsional plant. ADRC is a novel disturbance rejection control technique that is not completely dependent on mathematical models of physical systems. In ADRC framework external disturbances, system uncertainties, and internal dynamics of the system are estimated as a generalized disturbance by an extended state observer and the generalized disturbance is effectively canceled by a PD controller. A torsional plant represents a class of rotational systems. Its control challenges are the vibrations caused by mass imbalance, centrifugal imbalance, and the imbalance caused by the non-coincidence between the principal and geometric axes of rotating disc. In the thesis, the ADRC is applied to the torsional mechanism to control the angular speed and displacement of the rotating disc in the presences of the vibrations. Both simulation and hardware implementation results demonstrate the effectiveness of the ADRC. In addition, the hardware implementation results of the ADRC are compared with that of PD controller in terms of performance, control voltage requirement and tuning effort involved in the design process. The comparison study shows the superiority of the ADRC to PD controller