New soft robots really suck: Vacuum-powered systems empower diverse capabilities

We introduce a vacuum-powered soft pneumatic actuator (V-SPA) which leverages a single, shared vacuum power supply and enables complex soft robotic systems with multiple-DoF and diverse functions. In addition to actuation, other utilities enabled by vacuum pressure include gripping and stiffening through granular media jamming, as well as direct suction adhesion to smooth surfaces, for manipulation or vertical fixation. We investigate the performance of the new actuator through direct characterization of a 3-DoF, plug-and-play V-SPA Module built from multiple V-SPAs, and demonstrate the integration of different vacuum-enabled capabilities with a continuum-style robot platform outfitted with modular peripheral mechanisms. We show these different vacuum-powered modules can be combined to achieve a variety of tasks, including multi-modal locomotion, object manipulation, and stiffness tuning to illustrate the utility and viability of vacuum as a singular alternative power source for soft pneumatic robots, and not just a peripheral feature in itself. Our results highlight the effectiveness of V-SPAs in providing core soft robot capabilities and facilitating the consolidation of previously disparate subsystems for actuation and various specialized tasks, conducive to improving the compact design efficiency of larger, more complex multi-functional soft robotic systems. Summary We introduce a foam-based vacuum powered actuator and exemplary complex, multifunctional soft robotic system which it enables. Introduction Robots that operate in highly variable environments or in close cooperation with humans require both robustness and adaptability to ensure reliability and safety. These features can be accommodated most easily by adding compliance to a robotic system, which can be achieved either actively through impedance control methods (1, 2) or passively through compliant mechanical components and materials. In part, the advantage of a materialsbased approach to creating compliant systems is to offload some of the burden of complexity in control to morphological and material computation, in a sense, to achieve robust and adaptable behavior (3, 4). This latter strategy has been the recent focal point of the field of soft robotics, where inherently compliant and flexible materials such as silicone rubber are used to fabricate primary structural and active robot components (5). Various forms of soft pneumatic actuators (SPAs) powered by pneumatic pressure have been developed in this domain to compliment the nature of these soft materials, which stretch and bend through inflation or deformation of elastic chambers to produce useful mechanical work (6–16).