Development of a long-range untethered frictional microcrawler

This thesis examines the development and performance of a new type of microcrawler. The frictional microcrawler, as it is termed, is distinguished from previous microcrawling robots in that it operates by taking advantage of the friction/stiction present between its segments and the surface upon which it travels. It is driven by conventional thermal actuators that create a sequence of horizontal forces that push the microcrawler forward one segment at a time against friction forces. It can be precisely positioned by accumulating micron sized steps. It is capable of long-range reversible motion and is limited only by the length of the rails along which it travels. The microcrawler requires less than 3 volts to operate and it can travel at velocities exceeding 700 mum/s. It can develop a horizontal force greater than 130 muN and it continues to operate reliably while carrying a load of over 100 times its own weight of 1 muN. Experiments have shown that it can even climb a vertical wall. The effect of input frequency, actuation voltage, and size of contact area on the measured crawling velocity, force and power are presented and discussed.