A Layered Manufacturing Approach for Soft and Soft-Rigid Hybrid Robots

We present a manufacturing process for creating centimeter-scale multichambered inflatable robots and structures that can include both soft and rigid components. Our process uses a thermoplastic polyurethane (TPU) adhesive film to bond together layers of textiles, plastics, or other materials. The structures are heated and compressed a few layers at a time with a heat press machine or bonded in an oven all at once. We present two methods for arranging textiles and thermal adhesive film to achieve airtight structures and perform modeling and measurements on the resulting inflatable chambers. We characterize the set of textiles and rigid materials that will work with this process, measuring how strongly the TPU film bonds with them. We also describe how to include corners, where several pieces of material come together at a point, and determine which corner constructions are airtight. We characterize how different seam widths behave, determine the maximum pressure chambers fabricated with this process can support, and determine the cycle life of actuators built with this process. Finally, we present an actuator with an embedded sensor and three examples of robots constructed with textiles and TPU film, including a hybrid soft/rigid robotic arm, a soft robot that can roll along the ground, and a robot that can climb inside tubes or other confined spaces.