Development of a locomotion robot using deformable dielectric elastomer actuator without pre-stretch

This study proposes the development of a locomotion robot using a deformable dielectric elastomer for actuation without pre-stretch. Electroactive polymers ( EAPs) that are driven by electrical stimulation have recently garnered attention. Among EAPs, dielectric elastomer actuators (DEAs) are focused herein. DEAs have a structure wherein a dielectric is sandwiched between elastic electrodes. The performance of the DEA depends on the relative permittivity, Young's modulus, and the applicable voltage of the dielectric material. DEAs are usually used with pre-stretching, because of the material properties of the dielectric, which requires a large stress in the initial stage of extension, and the increase in the displacement of DEAs with the application of pre-stretch. However, because rigid frames are generally used for prestretching, there are few DEA applications that utilize their flexibility. Therefore, we focused on slide-ring materials (SRMs) as new dielectric materials. SRMs are polymer materials in which the cross-linking points move freely, and having excellent properties as dielectrics for DEA applications. Thus, pre-stretching is not required, and applications utilizing the flexibility of DEAs is possible. In previous research, a bending unit that did not require pre-stretching was manufactured by attaching non-stretchable tape to one side of the DEA using an SRM as the dielectric material. In addition, a locomotion robot with a bending unit was developed, and it was confirmed that the robot achieved locomotion because of a phase difference between the units. However, the basic characteristics of the bending unit and locomotion robot were not discussed. Therefore, in this research, we measured the frequency characteristics of the bending unit alone and demonstrated the locomotion of the robot.