Single-crystal Silicon Torsional Actuator Arrays for Micro Manipulation Tasks

Arrays of electrostatic MEMS actuators have been fabricated using a multi-layer SCREAM (Single-Crystal Reactive Etching and Metallization) process. The high aspect ratio single-crystal silicon (SCS) devices consist of released, torsionally suspended grids with tips. Experiments and calculations show that the actuator array is strong enough to move macroscopic parts. An individual actuator can generate a force of approximately 10 N and a displacement of 5 m. We describe manipulation experiments in which small, at objects were lifted and moved. Monolithic arrays have been built reaching a size of up to 10 cm 2 , with up to 15,000 individual single-crystal silicon actuators on one chip. MEMS actuator arrays can be used to generate a programmable force vector eld for the manipulation of small, at objects. We develop a theory of sensorless manipulation for pro-grammable force vector elds. It is shown how simple actuator control strategies can be used to uniquely align a part up to symmetry. These manipulation strategies can be computed eeciently and do not require sensor feedback. This theory is applicable to a wide range of microactuator arrays.