High-impulse and reactant-regenerative combustion-based micro actuators

The use of combustibles in micro-actuator technologies enables powerful impulsive actuation capabilities comparable to those of natural organisms. However, the exogenous dependence of fuel limits the development of combustion-based actuators. We present a closed-cycle reactant regeneration strategy wherein the bidirectional interconversion between hydrogen and water achieves real-time fuel replenishment for reactant-regenerative electrolysis and combustion reactions. Based on this, we develop a 1.5-centimeter actuator that generates forces above 20 newtons and operates continuously for >7200 cycles without refueling (a two orders-of-magnitude improvement over existing combustion-based actuators). Experiments confirm its strength and cross-environment versatility for removing obstacles, jetting, and striking via underwater cavitation. These features enable the actuator to be integrated into small robotic platforms, allowing them to reconfigure local surroundings in an active manner.