Re-imagining the Robots of Tomorrow
Our future might be a little softer than we imagined.
Written by Thomas Cahoon
Special thanks to Lisa Donnelly at Soft Robotics Inc. for use of relevant pictures.
A robotic bartender on a spacecraft hands a perfectly poured cocktail to a waiting patron, its mannerisms pleasant and efficient. A soldier straps into a mechanized suit, allowing him to run and fight at superhuman levels. A patient marvels at her new prosthetic arm, watching as the whirring servos and pistons adroitly actuate her new metal fingers. Everything is steel and glass, sleekly contoured and, of course, chrome-plated.
These sorts of scenes are familiar to anyone who has seen a sci-fi movie, and it seems like we are heading towards making them a reality. Robots are progressing by leaps and bounds, with the technology we use today being what the previous generation could only dream of.
Though, if you were to travel back to the 1970s, you might find that the retro-futuristic view was flawed. We have yet to develop some of the ideas they predicted and have developed others they never conceived. Our views of the future are constantly shifting to match emerging technologies. For example, we are now less enamored with the notion of flying cars (à la The Jetsons) but are excitedly waiting for the day when we can relax in the backseat while they drive themselves.
A constant problem plaguing roboticists is how to resolve the potentially dangerous capabilities of machines with their relatively delicate users. Current solutions involve either complex sensor systems that detect dangerous situations and make split-second reactions to avoid them or simply keeping people and machines in separate areas, as seen in automated factories.
New technologies are shifting the direction of the human-machine interface. As such, a large divergence from our current view is on the horizon, questioning the hard and sleek aesthetic we’ve come to expect and leaving it a bit…. squishier.
And with this, soft robotics enter the scene.
Soft robots are constructed using highly compliant materials (such as rubbers, fabrics, and cables), giving them increased flexibility and conformity. Often drawing inspiration from nature to inform their designs, their motion tends to be more biological than the gears and motors that make up their rigid cousins. This translates to a machine that will bend and twist to naturally conform to its environment, allowing them to excel in the field of human interaction.
Soft robotics don’t rely on individual pivot points or sliders like traditional machines, giving them theoretically infinite degrees of freedom. This means they operate in an underactuated state, allowing them to quickly adapt to different conditions. To better illustrate this point, imagine sitting in a wooden chair (traditional) versus a beanbag (underactuated). The wooden chair supports you in a set position while the beanbag would deform around you to match your curvature. This compliance helps soft devices work well in uncertain environments, which is always important when dealing with humans.
Aside from soft robots’ ability to adapt well, the lack of hard materials makes them inherently safer and creates a non-threatening aesthetic. This, coupled with their ability to absorb impacts without fear of breaking, makes soft devices an ideal medium for technology to interface with people.
Already we are seeing examples of soft robots designed for use around humans. Because their muscle-like motion makes them well-suited for augmenting and simulating biological motion, the medical field has been a forerunner in exploring their uses as prosthetics, occupational therapy devices, and even surgical instruments. Soft devices can affix directly to body parts to help them move without fear of injury, assisting those suffering from myopathy. This can greatly aid in keeping our aging population independent by helping with everyday tasks from climbing stairs to opening jars. Even able-bodied people can benefit from these devices. Researchers at Harvard University have created a soft exoskeleton that gives a boost to walking and running efficiency by having a set of wires act as a secondary set of “muscles”, pulling in-sync with the user’s gait. This invention could be a godsend for people whose jobs require long days on their feet.
There are many other fields making use of these pliable wonders. Automated robots with inflatable, silicone fingers are being used in agriculture to pick fragile produce such tomatoes and lettuce. Whereas traditional robotics require fine-tuned sensing methods to prevent damage to the target, the soft fingers eliminate their need as gentleness is inherent to their design. In the emergency services field entirely soft, autonomous robots that squirm, slither, and swim are being developed with search-and-rescue in mind. The robots’ non-rigid form allows them to search for survivors in collapsed buildings by squeezing into confined spaces that would otherwise be inaccessible. As an emerging field, these examples are just a glimpse of their true potential.
Currently, the largest hurdle that soft robotics face is finding a feasible actuation source. Most soft devices rely on cable pulls or pressure differentials to achieve motion driven by electrometrical motors and air canisters or compressors, respectively. These bulky solutions introduce rigid components that can invalidate the point of using soft components in the first place.
Researchers are exploring novel actuation methods to circumvent this issue. A few designs for wearables have a secondary system that constantly stores air by leeching a little energy from everyday movements, effectively eliminating the need for electric compressors. Other solutions are more ambitious, from impregnating silicone with ethanol that boils and expands when exposed to a charge, to filling the device with electrolyte “blood”, turning the entire volume into a redox flow battery. And while these ideas are promising, until they can be proven to be reliable, integrated actuation methods, these robots are firmly leashed to their bulky, electromechanical cousins.
Does this mean we’ll soon be driving in inflatable cars and getting served mixed drinks by octopus-like androids? Probably not. The attributes that makes them appropriate for human-interaction means they are not well-suited for the ultra-fine and stability-driven work that traditional robots excel at. While not a complete replacement for traditional robotics, soft robots have an enormous advantage in the human-machine interface. Soft wearable devices are already giving people extraordinary abilities; robots are adopting tentacle-like grippers, silicone “animals” are exploring environments inside of laboratories, and that’s only scratching the surface of what is possible. In the future we will see hybrid systems emerge; the back-end mechanics made of traditional gears and motors and the user-facing side utilizing soft grippers and actuators, effectively harnessing the best of both worlds
So the next time you’re imaging that robot assistant of the future, maybe think a little less Rosie the Robot, a little more Baymax.