A micro mobile mechanism using thermal expansion and its theoretical analysis. A comparison with impact drive mechanism using piezoelectric elements

Thermal expansion of solid materials can be used as an actuating mechanism for micro machines. It produces as much displacement as piezoelectric elements, but has the problem of response speed for ordinary scale machines. Actuators using thermal expansion have the possibility of fast response if their sizes are small because of their high heat emission ratio. In addition there are the following advantages: simple actuator structure and easy fabrication process; various materials which can be adopted for the actuator; the ability to operate in high temperature and in vacuum; remote control by supplying heat with laser beam or RF electromagnetic wave. This paper introduces a micro motion mechanism driven by thermal expansion and then introduces a theoretical analysis on a motion mechanism using thermal expansion. In addition, a comparison with a piezoelectric element illustrates the characteristics of the actuator. A basic experiment using electric current heating type actuator shows the possibility of the thermal expansion actuator.