Scale effects and thermal considerations for micro-actuators

This paper analyses scale effects for actuator types which are strong candidates for micro-actuation: shape memory alloys (SMAs), electrostatic, electromagnetic and piezoelectric actuators. SMA actuators are studied in detail and compared to the other actuator types on a basis of force, response time, and power density. Much of the analysis is based on thermal aspects and scaling effects on both convective and conductive heat transfer, which is a quite novel approach. Results of this thermal analysis are effects on surface temperature and maximum current density of microactuators