Inkjet printing of soft machines

Soft machines and soft robots are an area of intense research because soft systems are safer to interact with, are better at handling fragile objects, can produce complex shapes with fewer transducers, are robust, and are ideal for wearable applications. However soft robots and soft machines are far from replicating the number degrees of freedom and the dexterity found in nature. Most soft machines are fabricated from silicone, use external pneumatic actuation, and lack sensing. To move towards soft machines with more degrees of freedom and higher dexterity new fabrication techniques are required. In this work inkjet printing is used to fabricate soft machines with integrated dielectric elastomer (DE) and hydraulically amplified self-healing electrostatic (HASEL) transducers. Two demonstrators are presented to show how printed silicone, printed electrodes, and printed channels can be combined into a multi-layer multi-transducer soft peristaltic pump. The peristaltic pump shows how inkjet printed channels and transducers can be combined to control the flow of liquids. A method of motion for soft robots is also presented. The slug drive is a soft robotic drive train consisting 28 densely packed HASEL actuators. By producing a wave of contraction the slug drive is able to inch forwards in a way similar to invertebrate animals. The demonstrators show how inkjet printing can be used to rapidly prototype soft machines with neatly and densely integrated soft transducers.