Analysis Method of Combustion-powered Actuators for Hopping Robots

The combustion-powered actuator shows a great performance on driving hopping robots. However, the analysis for driving hopping is limit due to its complex driving process interacting with dynamic and thermodynamic. In order that its analysis method could be obtained, two methods are conducted, and the merits of them are compared. First, the equations of combustion-powered actuators are obtained according to the combustion engine model. Second, the effects of the thermodynamic factors, including combustion duration, combustion quality index and combustion efficiency, are studied. The results show that the distance between the cylinder and piston changes little as these factors changes, when the pressure inside of the chamber is up to the maximum pressure. According to the conclusion, the combustion process during the driving process can be approximately considered as a constant volume combustion. Third, based on the constant volume combustion hypothesis, the pressure is expressed as the function of the stroke and diameter in a closed formation. To verify this hypothesis, the simulations with the two models are conducted, which shows that the results are consistency with each other. According to the constant volume hypothesis, the pressure can be expressed in the closed solution, which is convenient for designing the parameters of the actuator.