Thermally-driven soft robots

Numerous types of actuators have been developed and used in soft robotic systems to date. Thermal actuators are one class of actuators that typically generate force due to thermal expansion or change of phase when exposed to a change in temperature. These actuators offer several potential benefits, particularly for small-scale and wearable soft robotic systems. We have recently developed several new soft robot designs that operate using thermally-driven actuators.

Recent relevant papers:

A. Sepehri, S. Kim, D. Agrawal, H. Yared, G. Dong, S. Cai, and T.K. Morimoto. "Bundled Liquid Crystal Elastomer Actuators With Integrated Cooling for Mesoscale Soft Robots." IEEE Robotics and Automation Letters (2025).

S. Krishna, J. Martinez, N. O'Shea, C. Melentyev, S. Kim, G. Dong, S. Cai, T.K. Morimoto, "Towards Soft Steerable Vine Robots Using Actuating Polymers," In IEEE 8th International Conference on Soft Robotics (RoboSoft), 2025, accepted.

Liquid crystal elastomer (LCE) is a promising material to develop thermally-driven soft actuators due to its high force density, large elastic strain limits, and mechanically programmable nature. However, the bandwidth of these actuators is typically well below 1 Hz, therefore limiting their potential use cases. In this work, we developed a new thermally driven soft actuator that consists of several LCE units bundled together with integrated cooling in order to achieve both high forces and bandwidths over 1 Hz. We also developed an electro-thermo-mechanical model and established design guidelines for developing our actuators for future soft robotic applications at the mesoscale.

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