Revolutionary robot shorts improve the walking efficiency of the elderly

Revolutionary robot shorts improve the walking efficiency of the elderly

As people age, their ability to walk decreases, leading to mobility limitations and affecting independence and overall quality of life. Therefore, researchers are interested in developing solutions that improve mobility, and wearable devices are a possible solution in robotics.

However, such portable robotic devices are limited to laboratories due to their weight and size. Several studies are working on deriving lightweight construction solutions.

As part of this effort, researchers at Heidelberg University have developed a robotic shorts called WalkON that is designed to improve walking efficiency in older people by supporting hip flexion. The device is designed to be worn over normal clothing and could serve as an everyday walking aid.

WalkON has one motor per leg, which winds an artificial tendon on a spool (35 mm diameter). The weight of the system is 2.93 kg and is distributed at the height of the user's center of mass to minimize the effects of additional mass. WalkON is attached to the body with a flexible textile structure.

Textile blueprintTextile blueprint
(a) WalkON waist belt and layer composition. (b) Internal view of the thigh textile belt and closed configuration.

“The main goal of this technology is to improve the autonomy and energy efficiency of its users when walking, with a particular focus on supporting the elderly.” says the study.

The hip joint plays a crucial role in activities such as ground clearance or climbing stairs. The hip joint in particular proves to be critical as we get older. WalkON eases effort by using an artificial, tendon-controlled design to help spread the upward movement of the legs. Portable and lightweight design provides users with a natural leg movement pattern.

Additionally, the study showed that WalkON can reduce the metabolic cost of walking compared to unassisted walking. The metabolic cost of walking is the amount of metabolic energy required to cover one unit of distance.

WalkON hardware componentsWalkON hardware components
(a) Computer-aided design of WalkON (b) Inertial Measurement Unit (IMU) sensors transmit hip motion data to the control unit via Bluetooth Low Energy. This unit runs the control algorithm on a microcontroller. The output is a speed command sent to the actuators. The generated motor torque is transmitted to the user's leg via the tendon-driven transmission. (c) The textile structure of WalkON consists of a hip belt and two thigh straps. (d) To guide the artificial tendons, anchor points are attached to the belt and thigh strap.

Researchers examined the effects of WalkON by studying older and young adults. Teens were asked to walk a 500m uphill outdoor hiking trail, and the study found that WalkON reduced the metabolic cost of transportation by 17.79%. Additionally, participants reported better control over their movements using WalkON.

Depression and obesity increase the likelihood of hip pain

When walking a flat 400 m outdoor route, older people reduced their metabolic costs by 10.48% with WalkON.

WalkON designWalkON design
a: An older adult uses WalkON to walk outdoors. Photography by Uwe Anspach. b, WalkON's design consists of a textile structure that includes a waist strap and two thigh straps that can be worn comfortably over normal clothing. The actuation mechanism is based on a tendon-driven transmission, in which artificial tendons are connected to the front part of the user's legs. These tendons are motor-actuated according to the user's gait cycle. Motor commands provide assistive forces during the swing phase of each step according to hip joint kinematics recorded by inertial measurement units (IMUs) in the sagittal plane.

“WalkON has been shown in a technology evaluation with young people and an effectiveness study with older adults to improve the energy efficiency of walking, contributing to improved mobility. In trials with young participants, WalkON provided an average energy saving of 17.79% compared to walking unassisted, while in older adults we observed an average reduction in transportation costs of 10.48%.”

“In practice, these savings equate to 10.3 kg and 6.3 kg of waist relief for young and older adults, respectively.”

Magazine reference

  1. Tricomi, E., Missiroli, F., Xiloyannis, M., Lotti, N., Zhang, X., Stefanakis, M., Theisen, M., Bauer, J., Becker, C. & Masia, L. ( 2024). Soft robotic shorts improve outdoor walking efficiency in older adults. Natural machine intelligence1-11. DOI: 10.1038/s42256-024-00894-8

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