Position control of a brushless DC servomotor using a sliding mode model following control (SMFC) system

The design and implementation of a DSP-based brushless DC motor servo control driver with a sliding mode model following control (SMFC) strategy are presented to achieve accurate servo tracking in the presence of load variations, parameter variations and nonlinear dynamic interactions. The SMFC algorithm uses the combination of model following control and sliding mode control to improve the dynamics response for command tracking. The control function is derived to guarantees the existence of the sliding mode. Furthermore, a modified proper continuous function is introduced to overcome the chattering problem. Experiments were carried out with sinusoidal command inputs. Experimental results are presented to demonstrate the superior tracking performance of our controller over the IVSC and FIVSC approaches. Moreover, the SMFC strategy is shown to be robust to plant parameter variations and external load disturbances.