Active disturbance rejection approach with application to precision motion control

Precision motion control applications require high accuracy, fast dynamics and robustness performances. The success is dependent on not only advanced technology in actuators and measuring instruments that provide physical realization hardwares, but also innovative control approaches that contribute to performances improvement. This paper presents a design and realization framework of active disturbance rejection strategy for precision motion control problems. The approach deals with the external nonlinear friction, working load and other uncertainties of a motion control system, and the internal plant dynamics variations to be generalized disturbances. Such disturbances are estimated by a unique extended state observer in real time and actively compensated for by a proportional derivative controller. Moreover, the feedforward control is usually involved in the framework to improve the dynamic performances of the motion control system. For purpose of physical realization of the control algorithm, applications of general DSP and FPGA technologies are introduced to simplify and improve the realization. Finally, a precision motion control example is given to explain the design procedure and industrial application. The initial success provides a new robust motion control design approach.