Low Noise, High Efficiency Hydraulics for Mobile Robots

Hydraulic actuation systems for mobile robotics are characterized by high bandwidth, high power density, robust operation, flexible power transmission but also by low efficiency, high rejected heat, and high noise levels. The undesirable characteristics of hydraulic power systems are not inherent to fluid power transmission; they are the result of the highly inefficient techniques used to control the power delivered to individual actuators. The spool valve architecture that dominates hydraulic servo systems has roots in gasoline powered heavy equipment where efficiency and noise are not primary concerns; this architecture is not appropriate for modern mobile robotics. Berkeley Bionics has been a leader in innovating novel hydraulic systems for mobile robotics from our roots working with hydraulic servo systems on the DARPA exoskeletons program at the University of California, Berkeley. Our current third generation HULC exoskeleton, under development with Lockheed Martin, uses proprietary hydraulic components and non-standard servo controls. Currently our electro-hydraulic actuation systems have overall efficiencies nearing 50%. The proposed project builds on our industry leading technology to design an electro-hydraulic actuation system that will rival the overall efficiency of an electro-mechanical actuation system, while maintaining an extremely low audible signature and the intrinsic benefits of hydraulic actuation.