PIEZOELECTRIC ACTUATION TO REDUCE PUMP FLOW RIPPLE

Pump flow ripple is a source of noise and pressure fluctuation that can result in unwanted behavior and failure of a hydraulic system. The intent of this paper is to present and model a novel method to reduce flow ripple using piezoelectric actuators, which are currently limited to applications in micro-scale pumps. The paper presents two methods for reducing pump flow ripple in a hydraulic system. The first method uses a piezoelectric actuated valve which governs the pump displacement. The second method employs a piezoelectric actuated cylinder that acts directly on the outlet fluid to reduce the flow ripple from the pump. Method one was not able to reduce the flow ripple due to the bandwidth limitations of the swash plate actuation cylinder. Method two was able to reduce the flow ripple significantly. Further improvements on method two were achieved by increasing the number and size of the piezoelectric actuated cylinders acting at the pump outlet. After optimization, it was found that method two was found to decrease pump ripple by up to 53.5% from the baseline pump output. Though method one is largely unsuccessful, it is found that method two is successful and becomes more effective as the number and size of the piezoelectric actuated cylinders increase.