The Right Trousers: developing the tech for robot-assisted trousers
The Right Trousers is a research project to develop robot-assisted trousers or socks to help the elderly and others achieve better and faster mobility. It is a collaboration between several universities, including the University of the West of England (UWE Bristol).
While the University is involved in investigating what people want and don’t want in a device that helps them move better, Bristol Robotics Laboratory (BRL), based on UWE Bristol’s Frenchay campus, is exploring how soft robotics can be used to develop and best adapt materials to make trousers that are comfortable and easy to use.
“If the trousers are going to be useful, they need to satisfy all the requirements of the people who will wear them”
Deciding how best to design potentially revolutionary robot-assisted trousers that could help people walk better is no easy task and a good starting point is to find out what future users of the garments might want.
In order to make the best possible trousers, the BRL team analysed findings drawn from UWE Bristol’s research, which involved several interviews and focus groups with the elderly and others who might benefit from mobility aids.
“Engineers like to simplify the problem but if the trousers are going to be useful, they need to satisfy all the requirements of the people who will wear them – that’s where our work came in,” says UWE Bristol’s Dr Ailie Turton, who led the research on user perception and engagement.
“It came out very strongly that people didn’t want to sacrifice any independence when using the devices,” says Ailie.
“BRL is exploring how soft robotics can be used to make the ‘right’ trousers”
Coupled with this, comfort was also a feature that potential users considered important and in up to 75% of cases, existing assistive devices like exoskeletons go unused because they are uncomfortable or too difficult to put on. For the project, BRL is exploring how soft robotics can be used to make the ‘right’ trousers. Soft robotics uses highly compliant materials and is thus a technology that lends itself well to robotic mobility devices that are light and comfortable.
The focus groups also pointed to the fact that some people cannot stand up for a long time to undertake tasks such as washing the dishes. Based on this evidence, BRL is looking at the possibility of soft devices that become stiff at the press of a button so that the user can stand steadily when scrubbing an oven dish.
Such an aid could be in the form of an external knee orthotic that is soft and comfortable. The technology could also be used to assist people with ‘foot drop,’ a condition that makes it hard to lift the front part of the foot and toes when walking and can lead to unstable mobility.
Ionic polymer metal composites (IPMCs) are a material that BRL is also experimenting with to make the trousers. IPMCs contain ions (charged atoms) that are asymmetric. When a small voltage is applied to the particles, some of the ions move to one side of the IPMC, thereby repelling each other, and this produces bending. The technology could therefore be used to build an artificial muscle, but still needs adapting to contain enough power to be used in orthotic devices.
Another source of power for the trousers could be compressed air. The BRL team is exploring how best to use pneumatic actuators, whereby an air supply is pumped into a shape to make it move. One variety of the system that could be adapted to mobility-assistance is a PneuNet (short for ‘pneumatic network’), which contains individual channels that fill up with air and apply flexion.
“You can design it to produce any motion you like and as each chamber fills up, it bends the whole shape,” explains Dr Tim Helps, who is BRL’s Research Associate on the project. “Although pneumatic actuators are not a new technology, the challenge is to build a system that does not rely on air tanks that are heavy to carry,” he explains.
Adapting tech: the team experiment with more efficient methods using PneuNet technology
A more innovative technology developed as recently as 2014 that could be used for the project is the coiled polymer actuator. These spring-shaped coiled polymers are very strong, but because they need heating up and cooling down again, they are quite slow to act. “This could be useful in some circumstances when users need the device to act slowly but steadily,” says Tim. “If people are getting up from a chair or climbing stairs, this technology would be more suitable than other methods,” he adds.
The ‘Right Trousers’ project involves many partners. UWE Bristol and BRL’s research is a part of other work running in parallel to produce a prototype device in 2018. The University of Southampton is working on physiological interaction e.g. functional electrical stimulation, while the University of Nottingham is exploring smart materials. The University of Leeds is researching control (e.g. gait detection), rehabilitation, and prototype-building using 3D printing. Finally, the University of Strathclyde is evaluating biomechanics using motion capture.
Arriving at a final product that incorporates all the knowledge from across the universities is expected to take a decade.