Multiple-degrees-of-freedom dielectric elastomer actuators for soft printable hexapod robot

In this paper, we present the development of a printable hexapod walking robot driven by the multiple-degrees-of-freedom (multi-DOF) soft actuators based on dielectric elastomer. The multi-DOF soft actuators are employed to provide versatile movements including two translations and single rotation within a simple structure based on the antagonistic configuration of two elastomer membranes. The soft actuators demonstrate the potential of being used as a multifunctional joint to actuate the robot leg's motion which biologically mimics the animal's walking posture. The actuator performances are enhanced by developing the novel mixed silicone compound, Wacker P7670 and Nusil CF2-2186, and applying the optimized prestrain to the silicone-based actuator membranes. A theoretically and experimentally comprehensive study was carried out to investigate the soft actuators performances in terms of linear displacements, deflection angle, output force, torque, dynamic response, and load carrying capability. We successfully demonstrated the robot's locomotion on the flat rigid surfaces with the forward and backward walking movements at an average speed of 3 cm/s (about 12 body-lengths/min) using the alternating tripod walking gait of insects.