Actuation and Sensing in Soft Robots
Spacesuits are important garments that are necessary to protect humans from the harsh environment of space. This includes protection from vacuum, extreme temperatures, radiation, space dust and so on. These spacesuits are pressurized and composed of 14 layers of material –making them bulky and difficult to move in. The strain of performing tasks for long hours in these suits causes fatigue and injuries, thus leading to suboptimal performances that can impact mission success. To address these issues, we propose a soft-robotic knee actuator that can provide an additional torque to aid in the bending of the knee. This exoskeletal actuator is composed of an elastomeric polyurethane (Carbon EPU 40) that can be powered by the pressure that exists within the spacesuit. It is soft, conformable and does not contain any rigid parts. The lack of a distal support system to power it makes it easy to implement and safe to operate. The biomechanical analysis of the EMU spacesuit with our soft-robotic actuator demonstrates the benefits that can be provided to the astronauts. Sensory organs enable us to interact with the environment. The human skin is the largest sensory organ, in terms of surface area, spanning 1.5 – 2 square meters in an average human adult. It covers the entire body and provides a wealth of information about the environment. We hypothesize that a synthetic skin capable of multi-modal sensing is a necessary component for a robot to interact with its environment with the same dexterity as animals. The synthetic skin we composed is a multilayer system embedded with optical waveguides that can sense external stimuli such as force, location, temperature and gestures. We use machine learning to model an unknown system and interpret data from the waveguides to enable the development of force, location, temperature and gestures models. As a proof of concept, we have developed a prosthetic arm composed of this synthetic skin that can detect and differentiate between multiple tactile stimuli such as force and temperature. Our skin may find applications in robotic skins and soft orthotics