Cut, Bond and Play: Volume-Preserved Reprogrammable Soft Pneumatic Actuators

Reprogrammable design enables soft actuators to change their performances after fabrication and obtain new deformation modes and functions. The reprogrammable design of soft pneumatic actuators is relatively difficult due to the intrinsic material being chemically inactive. This work proposes a new design concept for reprogrammable soft pneumatic actuators via volume-preserving cutting and bonding (VPCB) of solid silicone materials. The design concept and fabrication are presented to show the reprogramming process. As a result of VPCB, the incision becomes a key structural feature of this type of actuator, and the influence of its parameters on the deformation and blocking forces have been investigated. Simulation and experimental results show the large strain and nonlinear characteristics of these actuators. Then a ternary quadratic polynomial is chosen as the fitting model to fit the relationship between the deformation and the incision parameters within a prescribed pressure level and parameter range. And a multi-objective optimization based inverse design framework for this type of actuator is constructed. With the reprogrammable design and the inverse design framework, four real-life scenarios are chosen as the target configuration to verify the feasibility of the proposed design concept experimentally. The proposed VPCB design concept presents a new way for the reprogrammable design of soft pneumatic actuators, which does not involve external constraint structures and can always maintain the versatile of these actuators. It will provide inspiration for the development of new soft pneumatic actuators.