Robust control of a variable reluctance motor

A direct drive variable reluctance motor for robotic applications is considered. A cascade control structure is adopted, with an inner torque loop and an outer velocity loop. The inner loop consists of a static torque precompensator transforming the torque control problem into a current or flux control one. Optimization techniques that minimize power dissipation under the voltage limit imposed by the power amplifier are used to define an optimal ripple-free flux profile. Sliding mode implementation of the inner controller is considered, while the outer loop is designed using binary control techniques to achieve insensitivity to load and inertia variations. The drive is simulated for a single-link robotic arm, showing good performances in terms of residual torque ripple and velocity-tracking capability