Field-Programmable Stress-Engineered MEMS Microrobots: Design, Modelling, Fabrication and Control

We present an approach to programming of stress-engineered MEMS microrobot in the field using post-release stress engineering implemented with a set of in-situ configurable shadow masks and a new sub-linear behavior-differentiating (BD) control strategy that can be used to efficiently maneuver the robots to reach a target goal configuration. A MicroStressBot consists of an untethered scratch drive actuator (USDA) which provides forward motion, and a steering-arm actuator that determines whether the robot moves in straight line or turns. The ability to automatically set the masks to a desired configuration allows for efficient in-situ programming of the electrostatic control voltages of field-programmable (FP)-MicroStressBots. Independent control of many MicroStressBots is achieved through behavior-differentiation by programming the arms of the individual microrobots in such a way that the robots move differently (have different behavior) from one another during portions of an applied global control signal. We validate this control strategy with experimental results demonstrating its application to subsets of FP-MicroStressBots. Our control strategies present an important step for the development of scalable multi-microrobot control, enabling independent control of large number of MicroStressBots.