University of Fribourg, Switzerland
Adolphe Merkle Institute


Invited Talk

Bio-inspired Soft Robots

Soft, earthworm-like robots that are mechanically compliant can, at least in principle, navigate through uneven terrains and constricted spaces that are inaccessible to traditional legged and wheeled robots. However, most worm-like robots reported to date contain some rigid components, such as electromotors or pressure-driven actuation systems, which limit their compliance. We present a mechanically compliant worm-like robot with a fully modular body that is based on soft polymers. The robot is propelled by strategically assembled, electrothermally activated polymer bilayer actuators. To maximize the performance of these elements, we developed semicrystalline polyurethane that display exceptionally large nonlinear thermal expansion coefficients. The individual work segments were designed on the basis of a modified Timoshenko model. Finite element analysis simulations were used to describe their performance. The robot’s movements are controlled by electrical activation of the segments with basic waveform patterns. It can move through repeatable peristaltic locomotion on exceptionally slippery or sticky surfaces and it can be oriented in any direction. The soft body enables the robot to wriggle through openings and tunnels that are much smaller than its cross-section.