SBIR Phase I: Feed Forward Hydraulic Ripple Cancellation

The broader impact/commercial potential of this project is expected to be realized in two principal areas. There have been extensive efforts to mask hydraulic noise, but the proposed effort is directed at eliminating the hydraulic ripple before it is created at the source. Traditional passive methods of masking noise are insufficient because they work effectively only in a limited operating range. This is inadequate because hydraulic systems typically must operate over a wide range of speed and loads. First this project is expected to make hydraulic active suspension systems quieter, more responsive and robust and, therefore, more readily and widely adopted by industry. The resulting likely increased use of active suspension systems will, therefore, have the added societal benefit of improved vehicle safety and comfort. This project is also expected to have a much wider impact on the hydraulic noise that has been a chronic pain point for the hydraulics industry for decades. It will allow for the manufacture of quieter and more durable hydraulic pumps for many applications beyond active suspension. This Small Business Innovation Research (SBIR) Phase I project is an investigation of the feasibility of using an active buffer to eliminate flow ripple from a hydraulic pump, such as a gerotor pump. In a representative hydraulic system, the gerotor pump is at the heart of an advanced electro-hydraulic, active suspension actuator. Due to their geometry, positive displacement pumps provide small fluctuations in their fluid flow rate at a constant pump RPM. These small changes in flow rate create pressure fluctuations that can create significant mechanical movement that results in objectionable or unhealthy noise. The proposed effort is directed specifically at mitigating acoustic and structural vibration noise caused by such a pump. The proposed effort will utilize a combination of advanced experimental and computer simulation techniques to demonstrate the viability of the approach in the representative hydraulic system (an active suspension actuator). Hydraulic system noise is a widespread pain point in numerous applications involving hydraulic pumps. A key difficulty with hydraulic pumps is that they are often required to perform over a wide range of speeds and pressures. Conventional noise control devices typically can only be optimized for a relatively narrow portion of this range.