ARRIpede: A stick-slip micro crawler/conveyor robot constructed via 2 ½D MEMS assembly

Abstract

Recent advances in 2frac12D and 3D hybrid microassembly using MEMS snap fasteners and die-level bonding for interconnects, makes possible the miniaturization of exciting new small robots configured for various functions, such as flying, crawling, or jumping. ARRIpede is one example of a ldquodie-sizerdquo crawling microrobot constructed by assembly and die stacking. It consists of a MEMS die ldquobodyrdquo, in-plane electrothermal actuators, vertically assembled legs, and an electronic ldquobackpackrdquo to generate the necessary gait sequence. The robot has been designed using a stick-slip simulation model for a target volume of 1.5 cm times 1.5 cm times 0.5 cm, a 3.8 g mass, and velocities up to 3 mm/s. Even though work remains to be completed in packaging the robot, we demonstrated that the robot design is sound by experimentally evaluating the leg actuation force, the payload carrying capacity, the power consumption, and the manipulation ability of an inverted ARRIpede prototype. A configuration that carries a payload approximately equal to its own weight shows excellent steering ability. A reasonable match between simulations and experiments is noted, for example, when the legs are actuated at 45 Hz and 10 V, the crawling velocity of the microrobot was experimentally measured to be 0.84 mm/s or 18.7 mum per step, while the simulated leg displacement was 18.5 mum per step. The prototyped ldquoconveyorrdquo mode had a maximum measured linear velocity in excess of 1.5 mm/s, while consuming approximately 500 mW of power. We expect that for achieving lower speeds, such as 0.15 mm/s, the power consumption can be reduced to a few mW, enabling untethered operation.