This is the first paper to discuss the design and implementation of mu
ltiple fuzzy logic controllers in servo drives. Both ac and de drives
are considered since both types are used in high performance applicati
ons and their basic control structures are similar. The progressive de
velopment of single and multiple fuzzy logic controllers and detailed
simulation and experimental results are presented for servo drives inc
orporating interacting fuzzy controllers. For the dc drive considered,
the controllers are a speed controller, an armature current controlle
r and a flux (field current) controller. In the case of the fully digi
tal ac drive, a fuzzy speed controller is implemented in real time usi
ng 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 advanta
ges of a fuzzy approach to the design of variable speed drive systems
are also discussed together with practical considerations for implemen
tation.