Polymer Actuators for Micro Robotic Applications

In this thesis a multilayer actuator structure is developed for the I-SWARM project. In order to build an energy efficient and low voltage actuator system for the 3x3x3 mm robot, the resonance drive mode in combination with a ten layer multilayer structure build upon the most suitable substrate material was used. Two different sizes of the locomotion module were built. The first one is five times larger than the small version. It has five active layers and is simpler to work with and to test. The small module has three 2x0.4 mm cantilevers on a 3x3mm body and ten active layers. The multilayer process involve easily defined flexible printed circuit (FPC) board as substrate material, spin coating piezoelectric poly(vinylidenefluoridetetrafluoroethylene) P(VDF-TrFE) as active stack material, and evaporated aluminum electrodes on each active polymer layer. By using different shadow masks for each electrode layer, special inter contact areas can be contacted from above after the polymer has been removed by an Inductively Coupled Plasma (ICP) etch. The contours of the locomotion module was etched in a Reactive Ion Etch (RIE) equipment. Both the cupper layer in the FPC and the electrode layers of the active stack, were used as etch mask. The deflections of the cantilevers were measured at low voltages to ensure as realistic drive voltage as possible for the I-SWARM robot. The large structure showed a 250 μm deflection at 4 V and 170 Hz resulting in a Q-value of 19. The deflection of the small structure was 8 μm at 3.3 V and 5000 Hz and the measured Q-value was 31.