Robotic cane shadows stride to stabilise walking

Researchers at Columbia University have developed an autonomous robotic cane on wheels that tracks the stride of its user, providing support during walking.

The device is engineered to mimic the light touch of a guiding companion, allowing the user to take narrower strides that keep the centre of gravity in place and prevent wobbles. It’s hoped a refined version of the technology could be introduced to assist the elderly or people with mobility difficulties. The work is published in the IEEE Robotics and Automation Letters.

“Often, elderly people benefit from light hand-holding for support,” said research lead Sunil Agrawal, professor of mechanical engineering and of rehabilitation and regenerative medicine at Columbia Engineering.

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“We have developed a robotic cane attached to a mobile robot that automatically tracks a walking person and moves alongside. The subjects walk on a mat instrumented with sensors while the mat records step length and walking rhythm, essentially the space and time parameters of walking, so that we can analyse a person’s gait and the effects of light touch on it.”

To test the device, the Columbia team fitted 12 healthy subjects with virtual reality headsets that created a visual environment to unbalance their walking gait. The subjects then each walked 10 laps on the instrumented mat, both with and without the robotic cane, in a variety of conditions that tested walking with visual disturbance.

In every virtual scenario, the light-touch support of the robotic cane caused all subjects to narrow their strides. Narrower strides mean a decrease in the base of support, but this corresponds to a smaller oscillation of the centre of mass, indicating an increase in gait stability due to the light-touch contact.

“The next phase in our research will be to test this device on elderly individuals and those with balance and gait deficits to study how the robotic cane can improve their gait,” said Agrawal, who directs Columbia’s Robotics and Rehabilitation (ROAR) Laboratory. “In addition, we will conduct new experiments with healthy individuals, where we will perturb their head-neck motion in addition to their vision to simulate vestibular deficits in people.”

Mobility impairments affect around four per cent of people aged 18 to 49, rising to 35 per cent  per cent of those aged 75 to 80 years. By 2050, it’s estimated that there will be only five young people for every old person, compared with seven or eight today.

“We will need other avenues of support for an ageing population,” said Agrawal. “This is one technology that has the potential to fill the gap in care fairly inexpensively.”