Multi-Material Compliant Mechanisms for Mobile Millirobots

This paper describes a new process for fabricating planar, multi-material, compliant mechanisms, intended for use in small scale robotics. The process involves laser cutting the mechanism geometry from a rigid material, and refilling the joint areas with a second, elastomeric material. This method allows for a large set of potential materials, with a wide range of material properties, to be used in combination to create mechanisms with highly tailored mechanical properties. These multi-material compliant mechanisms have minimum feature sizes of approximately 100 mu m and have demonstrated long lifetimes, easily surviving 100,000 bending cycles. We also present the first use of these compliant mechanisms in a 2.5cm x 2.5cm x 7.5cm, 6g hexapod. This hexapod has been demonstrated moving at speeds up to 6 cm/s, with a predicted maximum speed of up to 17 cm/s.