Self-powered exoskeleton looks just like a running shoe

Dr Soheil Bajelan of the Institute for Health & Sport at Victoria University has developed what he understands is a joint world first in the rapidly expanding field of medical exoskeletons.

Exoskeletons are wearable devices that work in tandem with the user to augment, reinforce or restore human performance and are being developed for global applications in medical, military, civilian and industrial areas.

Dr Bajelan’s Self-Powered Ankle Exoskeleton (SPAE), the product of six years work, is ground-breaking because it does not require batteries or sensors. The exoskeleton harvests energy from the body movement of the user. “It produces energy itself. It does not need an external power source or a control system,” he says.

The device has attracted attention from the world’s largest prosthetics/orthotics companies in Australia, Germany, the United Kingdom and the United States.

In the medical field, wearable assistive technology is a fast-growing sector with a large proportion of future demand expected to come from the ageing population.

Falling by older people and stroke patients is estimated to cost the Australian health system up to $3.9 billion by 2050.

“If implemented widely, my SPAE will contribute to reducing falls and contribute to an estimated $32 million savings each year in medical costs for every one per cent reduction in falls.”

The SPAE minimises the risk of tripping and falling by actively controlling foot-ground clearance and obstacle crossing.

It also has the advantage for users of being unobtrusive and looks just like a running shoe with the technology embedded inside. “It’s an I-shoe,” says Dr Bajelan. “An intelligent shoe.

“I developed it from zero. My PhD took longer than it should because I did this from scratch. For six months, I would walk along the Maribyrnong River just thinking.”

Dr Bajelan’s invention is lightweight, low-cost and designed to be fully mechanical (passive) and untethered. It provides the same functionality as advanced robotic systems but does not have an actuator or external power source, therefore giving the user complete freedom. “I call this novel technology ‘Intelligent and biomechanically-safe gait energy harvester’,” he says.

SPAE was developed using biomechanical experiments, computerised modelling and simulation using cutting-edge biomechanical technologies. “Every part of SPAE has a scientific evidence background,” Dr Bajelan says.

A powered exoskeleton would have been a lot easier to develop, he says, but powered versions come with limitations that include the amount of time that they can be used before charging is required, and the requirement to carry a battery or be tethered to an external power source and require a control computer. They are expensive and complex and the type and extent of possible risks are yet to be understood.

“The future direction for SPAE would be to generate electricity from walking – ‘a green source of energy’ to power various smart devices and wearable gadgets,” Dr Bajelan says.

SPAE is now under provisional patent application. “I am working hard to establish a start-up company to industrialise this innovative robotic device to make it available for all Australian elderly people and stroke patients, providing them with a safer life. It would proudly be made in Australia,” says Dr Bajelan.