Active joints for microrobot limbs

In this contribution we propose an electrostatic actuator for active joints. The active joint consists of two plates, one of which is a bilayer and bent by the bimorph effect. The plates are clamped to each other at one edge. A voltage between the plates leads to a very large field at the clamp where the plates are in intimate contact, thereby producing a force large enough to pull the bent bimorph cantilever beam to the other plate. In this design we have an actuator in which large electrical forces acting over a short distance are used to produce large deflections. We see an appealing application of this actuation principle in active joints for robot arms, e.g., by attaching members to the actuator and by combining two or more active joints and members to form micro robot arms, legs and grippers.