Sensing, Actuation, and Control of Soft Fluid-driven Robots by Liquid-elastomer Composite Sensors and Dielectric Elastomer Actuators

Abstract

The compliance and robustness of soft robots make them promising alternatives to traditional rigid robots in many circumstances, such as human-machine interaction, delicate object manipulation, and unstructured environment exploration. Among various classes of soft robots, fluid-driven robots are one of the most widely used types in both research and industrial applications. However, the power systems for fluidic robots generally consist of inflexible and bulky components, which considerably limit the mobility and adaptability of these robots. There is a great need for power systems that match the size, mass, and mechanical properties of the soft fluidic robots. This thesis is an exploration of sensing, actuation, and control of soft fluidic robots using sensors and actuators made of elastomertic materials. We begin with developing biocompatible soft stain and force sensors that could be used on both robots and the human body for safe and reliable motion detection. Using these sensors, we build an electronic skin that are safe and comfortable for both children and adults. To achieve fast and powerful control of fluidic robots, we then shift gears to build a new class of millimeter-scale, electrically-responsive, and ultra-high power density dielectric elastomer actuators (DEAs). Further, we connect these DEAs with elastomeric fluidic channels, resulting in electrically-driven dynamic valves for fast and precise control of fluidic actuators. We realized both open- and closed-loop control of a macro-scale hydraulic actuator using these soft valves. Finally, by actuating two or more DEAs in sequence, we create an electrically-driven peristaltic pump that is able to drive and reliably control hydraulic actuators. Together with the elastomeric sensors and soft valves, it can be used as the power source for soft fluidic robots at multiple scales.