Electrohydraulic actuator based on multiple pouch modules for bending and twisting

There is a significant demand for the development of actuators capable of multimodal actuation for conducting the required tasks in an unstructured environment. In conventional mechanical systems, several components, such as motors, hinges, cranks, and complex controls, are utilized to realize various multimodal deformations. In this paper, we propose a multimodal actuator based on a soft structure without conventional components. The proposed actuator utilizes electrostatic and hydraulic forces to create diverse operating directions and modes. The actuator design presents a novel design that integrates the bending and twisting actuators based on a hydraulically amplified electrostatic mechanism. The combination of the input voltages of the electrode segments of the four-segment structure helps achieve bending and twisting motions. The multiple pouch modules interact with each other to generate the bidirectional multimodal motion. The results demonstrate the ability of the actuator to manage the direction and mode of operation using a special structure. This actuator achieves a tip displacement of up to 4.28 mm and a twisting angle of 9.8^°. These soft electrohydraulic actuators will provide new design ideas for mobile robots, manipulators, and biomimetic applications.