Health and wellness

Battery-powered leg that simulates ankle and tiny robot inspired by earthworms among inventions by young Hong Kong engineers vying for national award

Work of students at the Chinese University of Hong Kong could offer major improvements to quality of life for suitable patients

PUBLISHED : Tuesday, 01 August, 2017, 7:01am
UPDATED : Tuesday, 01 August, 2017, 4:05pm

An artificial leg which mimics the action of a natural limb is one of two innovations from local engineering students that will represent Hong Kong at an awards event against competition from across the country in November.

The leg, the work of two youngsters at the Chinese University of Hong Kong, could offer major improvements to quality of life for suitable patients, and has already scooped several local honours.

It employs a biomimetic design and electrical support to simulate the thrust of a real ankle.

The device will go up against inventions by students nationwide at the Challenge Cup in Shanghai.

Twenty-year-old Liu Yuanfu, who had a below-the-knee amputation of his right leg at the age of six, said the limb had helped him walk more easily by giving him supporting power from the heel.

“The traditional prosthesis I used had a fixed ankle and provided no extra power,” Liu said. “So I needed more strength to walk and couldn’t put my feet flat on the floor when sitting.”

Gao Fei, a final-year PhD student on the project with two others from the mechanical engineering department, said a compact spring mechanism and battery-powered motor made the difference.

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The spring mimics a natural ankle by storing energy built up from the lead-up phase of a person’s step. The energy is then released to help the wearer lift his or her artificial foot from heel to toe as the spring stretches. With additional power from the motor, the wearer can walk with less effort.

“Our testees consumed six to eight per cent less oxygen than when using the traditional prosthesis,” Gao said.

The leg has completed clinical trials on three amputees and will be ready for commercialisation soon. Gao said the unit cost of mass producing the limb could be reduced to 20,000 yuan (HK$23,178), about one-third of the market price of some rival branded powerless prostheses.

The second invention vying for an award is a tiny remote-controlled soft robot inspired by earthworms that could eventually be used to screen patients for colon cancer. It was created by four biomedical engineering students and measures just 9cm in length and 18mm in diameter.

A person controlling the robot can navigate the device, which takes the form of a worm-like silicon rubber tube, as it crawls and makes turns inside a patient’s colon.

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Pan Tianle, the 23-year-old lead researcher on the project, said the robot was safer than the flexible endoscopes used now and more controllable than a capsule endoscope, and could also be deployed at a lower cost.

But Pan said there was still a long way to go to apply it in a real-life clinical setting as the robot had yet to pass tests on a pig’s intestine.