Modeling and Control of a Planetary Compound System Under External Magnetic Load

Abstract

Abstract Many experimental setups that are used in characterizing gear and rotor dynamics employ noncontact hysteresis brakes to control the load torque as opposed to employing a clutch-type brake mechanism. Although hysteresis brakes are highly reliable maintenance-free torque resisting instruments, the presence of minor cogging torques within the brake is shown to physically mask the gear dynamics by causing a bistable region in the speed response function that is otherwise nonexistent. This paper investigates the dynamic characteristics of this experimental arrangement in detail and lays out a simulation-based tuning method for employing robust-adaptive sliding mode control (RASMC) to improve the speed response function of the gear drive. A global dynamic model is constructed from a set of piecewise-affine models that are experimentally validated over their applicable dynamic ranges. A proportional–integral (PI) controller is further developed and numerically tuned based on the global dynamics and is shown to compare well with the RASMC performance, testifying to the high fidelity of affine experimental models under limited information of the underlying analytical dynamics.