Stiffness Control of Thermally Driven Actuator Using Phase Transition

This paper proposes a method for controlling the stiffness of a thermally driven actuator by leveraging the phase transition of a low-boiling-point liquid. Using a Peltier device for cooling, the reduction in actuator stiffness can be precisely adjusted. Experiments demonstrated the actuator's effectiveness, particularly in handling fragile objects with precision, ensuring delicate interactions with contact surfaces. Since stiffness is adjusted within a safe temperature range, this approach shows promise for applications involving direct human contact, such as the outer surfaces of social robots (robot skin).