Comparative Study of Digital Hydraulics and Digital Electronics

Abstract Digital fluid power has gained substantial attention in the last decade and recently has been the focus of several fluid power conferences. Recognizing that digital hydraulics is an enabling technology for many new high-efficiency and novel hydraulic systems, this paper demonstrates that digital fluid power cannot simply be treated as an extension of the well-accepted digital technology in the electronics domain due to some key differences between the hydraulic and electrical systems. Digital hydraulics incorporates similar ideas as those from digital electronics with a goal of reducing the energy losses caused by the throttling of the fluid in typical hydraulic systems. A good understanding of the differences between hydraulic and electronic systems is needed because fluid and electrical properties are different. The compressibility and inertia effects of hydraulics are compared to the capacitance and inductance of electrical systems. The different actuation efforts of hydraulics and electronics are shown. Also, some of the different ideas for achieving hydraulic transformers are discussed. By understanding and accounting for the differences and similarities during the design process, novel digital hydraulic systems can be more efficient and effective while minimizing noise and vibration due to switching techniques.