Active Control of Rear Sub-frame Vibration in Rear and All-Wheel Drive Vehicles

Feedback control of the rear sub-frame structure is used to abate its gear mesh induced vibration. The goal of the active control is to absorb vibration at a location close to the perturbation source, i.e., the rear differential. Proof mass actuators (PMAs) are used in this active vibration control application. A tuned absorption-based as well as a linear quadratic active vibration control schemes, each with its own advantages and disadvantages, were developed for this application. Following to the synthesis and numerical simulation of the two active vibration control strategies, they were first evaluated on a test structure in the laboratory. Following the laboratory evaluation, one of the active vibration control strategies was implemented on an all-wheel drive vehicle. Two small PMAs, mounted on the rear sub-frame of the vehicle, were used as the active elements in this vibration control application. An accelerometer placed next to each actuator was used as the feedback sensor. The effectiveness of active vibration control in absorbing the shaker induced vibration of the sub-frame was successfully demonstrated. In addition, rolling dynamometer tests showed effective vibration reduction of rear differential induced vibration of the sub-frame. As expected, lowering the sub frame vibration resulted in lower vibration and noise in the cabin.