Design and DSP implementation of fuzzy controllers for servo drives

This is the first paper to discuss the design and implementation of multiple fuzzy logic controllers in servo drives. Both ac and de drives are considered since both types are used in high performance applications and their basic control structures are similar. The progressive development of single and multiple fuzzy logic controllers and detailed simulation and experimental results are presented for servo drives incorporating interacting fuzzy controllers. For the dc drive considered, the controllers are a speed controller, an armature current controller and a flux (field current) controller. In the case of the fully digital ac drive, a fuzzy speed controller is implemented in real time using the TI TMS320C30 DSP and is shown to provide stable, robust control. The design procedures and the drive responses are compared to those for conventional non-adaptive and self-tuning controllers. The advantages of a fuzzy approach to the design of variable speed drive systems are also discussed together with practical considerations for implementation.