Performance improvement of practical control method for positioning systems in the presence of actuator saturation

The positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, the ease of controller design and simplicity of controller structure are very important for practical application. For satisfying these requirements, NCTF (nominal characteristic trajectory following controller) has been proposed as a practical PTP positioning control. However, the effect of actuator saturation cannot be completely compensated due to integrator windup when the object parameters vary. This work presents a method to improve the NCTF controller for overcoming the problem of integrator windup. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is effective to compensate the effect of integrator windup.