Tunable segmented soft actuators

Many of the existing pneumatic soft actuators have a fixed response after fabrication. This means that once they are fabricated, the actuators always bend, twist or stretch in the same way upon inflation. In most cases, this is desirable because this way actuators can be designed specifically for a particular application. However, what if the application or environment in which the actuator is going to work is not yet known? In this case an actuator for which the response can be easily tuned would be very useful.

(Left) Segments with a slightly different response. (Right) Inflation sequence of a segmented actuator assembled from three segments.

In this project we fabricate extending actuator segments with a slightly different response (pressure-volume relation), that when combined, can result in segmented actuators with highly different (nonlinear) responses. The purpose of the project that is described here is to give a detailed description of the design, fabrication and testing of these soft actuators, and to provide a quick way to get you started with off-the-shelve components. For a deeper discussion on the theory and fundamental principles underlying these segmented actuators, we refer you to a previously published research article (J.T.B. Overvelde, T. Kloek, J.J.A. D’haen, K. Bertoldi, (2015) Amplifying the Response of Soft Actuators by Harnessing Snap-through Instabilities. Proceedings of the National Academic of Sciences of the United States of America).

The following movie uncovers the inspiration of the project, and shows some examples of segmented actuators that can be made using our approach.