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 µm 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 × 2.5cm × 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.