This work describes the modeling and control of a proposed actuation system that is capable of pressurizing a chamber volume via the catalytic decomposition of a liquid monopropellant controlled by a binary on/off propellant valve. Two design configurations of the actuation system are presented and common portions of both are energetically modeled. The parameters of the resulting dynamic model are meaningful physical properties of either the propellant or the system. A model-based switching controller is then applied to the task of pressure tracking. Model validation and controller performance are shown experimentally.

This paper describes the design of a liquid-propellant-powered hot-gas actuator appropriate for human-scale power-autonomous robots. A prototype of the actuation system is described, and closed-loop tracking data is shown that demonstrates good motion control. Experiments to characterize the energetic performance of the actuation system indicate that the proposed system with a diluted propellant offers an energetic figure of merit five times greater than a battery-powered by undiluted propellant would offer an energetic figure of merit an order of magnitude greater than battery-powered DC motor actuated systems.

This paper presents a liquid-fuel powered pneumatic actuator appropriate for human-scale autonomous robotics. The motivation for this work is the development of a lightweight actuation system with system energy and power densities significantly greater than a DC motor and battery combination. For the scale of interest, the design tradeoffs between complexity of an energy conversion system and fuel specific energy density make many conventional approaches inappropriate. Conventional actuation, such as a battery powered DC motor system, does not possess adequate energy storage to perform significant amounts of mechanical work for significant periods of time autonomously. A system design comparison for a six-degree of freedom walking robot is presented which compares the expected performance of a monopropellant powered actuation system to a battery powered DC motor system. Results from this comparison demonstrate the viability of such an approach and indicate significant increases in energy and power densities. A single-degree of freedom manipulator was constructed to demonstrate this approach. Experimental results corroborate the expected energetic advantages.