Active control of gear pair vibration with an electronically commutated motor as actuator

Transmission systems are often subject to harmonic disturbances originating from transmission errors. These transmission errors cause non-desirable gear pair vibrations at mesh frequency that generate airborne sound. An active control system to suppress gear pair vibrations due to transmission error excitation is presented. The proposed controller is an adaptive feed-forward controller based on the filtered-x LMS algorithm. In contrast to previous approaches the proposed controller acts directly on the desired torque input of the torque controller of an electronically commutated motor. Therefore this approach does not require additional actuators. An electronically commutated PMSM driving a single stage helical gear set is considered. In this case one of the gears is rigidly connected to the rotor of the PMSM. Analyses have been made in simulation with a two-degree-of-freedom model with a time-varying spring stiffness and a viscous damper. Results showed the control structure to be very effective in reducing gear pair vibrations. In simulation the dynamic transmission error was reduced by -74 dB.