Printed Flexible Actuators for Soft Robotics

Printed flexible actuators are an important component in soft robotics, enabling unique and delicate movements with simple mechanism. The main challenge is to fabricate flexible actuators that achieve large movements, towards fabrication of a soft walking robot.

Since there is a variety of triggers, such as: light, electric field, magnetic field, heat etc., there are various types of actuators and actuation mechanisms. In this study, two types of actuators were developed and studied: electro-thermal and magnetic.

Electro-thermal actuators are bi-layer devices in which the movement is caused by differences in thermal expansion coefficients of the two layers. For carbon nanotubes (CNT) based actuators, one of the layers is composed of CNTs which functions as an electrical heater and the other is a flexible polymer film.

The study focuses on the effect of the properties of the CNT, such as layer thickness and CNT type, on the movement of the actuator. In addition, new three layered structured actuators that perform large movements are presented, while combining polymers with various mechanical properties, including shape memory polymers that enable very complex movements.

The study also presents fabrication of 3D printed ferrofluid-based actuators, while studying the effect of the ferrofluid flow and the mechanical properties of the polymeric materials on the obtained movement. Actuators mimicking a human hand and a worm are demonstrated.