Development of Shock-Wave-Powered Actuators for High Speed Positioning

A shock wave is a compressive wave which propagates at supersonic speed. A shock wave is generated by the emission of energy for a very short duration by high speed phenomena, such as explosions, discharges, collisions, high speed flights, etc. Shock tube experiments have played an important role in the field of high speed gas dynamics. A shock tube is usually divided by a diaphragm into a driver section and a driven section. Generally, the initial conditions of the driver and driven sections are high and low pressure, respectively. When the diaphragm breaks, a shock wave is generated in the driven section. The density, temperature and pressure of the gas behind the shock wave rise discontinuously. The shock wave arrives at the end wall of the tube, and a reflected shock wave is generated by the reflection from the wall. The quantities behind the reflected shock wave rise further. If the shock wave can be generated continuously without the diaphragm needing to be changed, this phenomenon could possibly be applied to an actuator having a piston that moves at high speed. In this study, equipment powered by a shock wave is produced, and its performance is examined. The results show that piston movement generated by a shock wave is faster than that which is not and that the piston speeds depend on the initial conditions. Also, the characteristic of the actuator powered by the shock wave is revealed.