Soft, glove-like exoskeletons that rely on an inflatable membrane that expands for actuation are starting to gain some serious traction. Soft inflatables have a tremendous advantage over classical hand exoskeletons because the component that provides the movement force also provides the structural support. The inflatable hand exoskeleton is both the actuator and frame simultaneously in one. Like any power glove, inflatables can be used for rehabilitation or power augmentation. Some early prototypes also have the ability to change shape to better match the fingers and knuckles in the hand as they expand. Inflatable devices keep all of the advantages of soft exoskeletons over rigid ones: cheaper materials, lighter and more comfortable. In addition, they also have a leg up on classical soft exoskeletons that rely on pull/push force for actuation. Inflatables do not require an anchor point at the wrist or forearm nor the connecting rods or cables.
Soft Robotic Hand
Wyss Institute For Biologically Inspired Engineering at Harvard University
The Harvard inflatable soft exoskeleton glove appears to be the leader in this field. In the video featured above, we see an early prototype being used a by a person with muscular dystrophy. This in itself is rare as most rehabilitation exoskeletons are usually demoed by healthy individuals. The inflatable glove is more comfortable and can be worn longer than most rigid frame counterparts and the inflatable membrane is highly customizable. In a potential future mass production setting, the user’s hand will be scanned, the inflatable membrane will be cast (manufactured) and then wrapped around in an elastic outer layer. The controller, pressure regulators and compressor presumably can be housed in a backpack, waste satchel or even left on a nearby counter. Also take a look at this video of an older prototype from 2014 that has the inflatable membrane sacs exposed in which you can clearly see how the glove bends to conform to the knuckles in the hand.
Soft Robotic Glove
National University of Singapore, Evolution Innovation Laboratory (NUS EI LAB)
This is a somewhat simpler device that bends uniformly at the fingers. The NUS EL Lab team have more videos on their YouTube channel that show a lot more of their work with inflatables.
University of Texas Arlington
The UT Arlington inflatable exoskeleton glove is designed purely for rehabilitation purposes. After stroke or surgery, patients have to spend hours with rehabilitation professionals that assist them in re-training the hand grasping action. A low cost, inflatable exoskeleton glove that can provide gradually decreasing assistance could allow a professional to work with multiple people at the same time or even remotely.
Soft Robotics Toolkit
If inflatable robotics are indeed cheaper and require no frame or anchor points then the technology should be more accessible. At least that is what the folks at the Soft Robotics Toolkit Website seem to think! The site is a resource center on how to build your own soft robot with information on modeling, creating molds, controllers and suppliers. The site also features a numerous sample projects as well as a competition.
Beyond Hand Inflatable Exoskeletons:
Inflatable wearable technology does not have to be limited to hand-only exoskeletons. Last month we reported on Otherlab Orthotics that has a prototype of a full arm and even designs for a full body inflatable exoskeleton suit. Fundamentally however, a full inflatable suit will struggle supporting a heavy load. A combination upper body exosuit with its controllers and compressor supported by a load carrying rigid exoskeleton could become the new normal in full body wearable robotics!