Robotic Metamaterial with Odd Elasticity

Abstract

Going beyond naturally occurring materials, Metamaterials exploit a design at the microscale resulting in macroscopic behaviour, to achieve different or even new properties that can have a wide range of applications. By incorporating sensors, actuators and control, Robotic Metamaterials can achieve even more extremely different behaviour such as odd elasticity. By using local control and non-reciprocal couplings between actuators, an asymmetric elastic response can be achieved. Due to the non-conservative nature of this coupling, the system has a tendency to cycle and give rise to complex behaviours such as locomotion. Through simple and localized control, complex material behaviour is achieved, where the body is performing the computation and no complex control or computations systems are required.

In this work, a new unit cell for a metamaterial that achieves this odd elasticity is designed, manufactured, and finally tested. The unit cell consists of 3 hexagonal mechanisms with compliant joints and a linear actuator inside and is locally controlled. By using a novel Actuator design and engineering principles such as compliant mechanisms, a unit cell design is achieved that has 10 times smaller scale per area and 15 times higher strength-to-weight ratio compared to existing work. Finally, this unit cell was characterized and combined into a larger lattice showcasing the possibilities for future research into the behaviour of odd elastic metamaterials.