A mathematical model to design pillar-shaped bioinspired mechanical sensors

Abstract

Soft robots and sensor/actuator systems are often based on bioinspired designs to leverage nature patterns. Specifically, pillar-shaped sensors are useful for human activity monitoring, locomotion of soft robots or treatment of cardiovascular diseases. If electric or magnetic particles are added in the manufacturing process, these structures can be tuned through remote fields to attain a specific mechanical behaviour. This promising technique has direct applications in high-impact fields such as bioengineering, soft robots or sensor designing. Filament-shaped smart sensors can send electrical signals when subjected to an external mechanical stimulus or provide a mechanical response when a remote and controllable field is applied broadening their possibilities of action. As the efficient design of these structures is highly challenging, developing a technical tool with a low computational cost to help throughout layout processes (i.e. inverse engineering) is pivotal. Theoretical modelling of the kinematics and dynamics of a wire-shaped structure under an external action is the first step to provide a methodology to help designing mechanical sensors in an efficient, understandable and low time-consuming way. The event of mechanical deformation after receiving the external stimulus and before sending the corresponding output signal is key in the conceptualisation process of smart sensors. This work intends to give insight into the dynamics of a deformable pillar-shaped sensor component under an external action without addressing or coupling its causes and, hence, provide the general mechanical framework to serve as basis for multiphysics formulations for pillar-shaped sensor design.