If you have trouble standing up, an exoskeleton robot can help

Authors: Gao Dayong, Chen Jibao; Chief Judge: Zhai Hua

Unit: Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center)

This popular science work is one of the popular science materials in the series "Don't be afraid of spinal cord injuries, there are ways to prevent and rehabilitate them"

In everyone's impression, words like "spinal cord injury" and "paraplegia" mean that one can only be wheelchair-bound or even bedridden for a long time. Restoring standing and walking is also the hope of many patients with spinal cord injuries. With the advancement of technology, standing and walking are no longer an unattainable dream for patients with spinal cord injuries. Exoskeleton robots are one of the weapons that help them realize their dreams.

Exoskeleton robots can be seen as a technology that extends, supplements, replaces or enhances human functions and abilities. They can not only help patients with spinal cord injuries regain the ability to stand and walk, but also reduce the risk of pressure sores caused by sitting in a wheelchair for a long time, maintain normal joint mobility, improve heart health, muscle strength and psychological state, and relieve depression.

Development History

Early military use of exoskeleton robots

The technology dates back to the early 1960s, when the U.S. Department of Defense first proposed the concept of powered “armor.” At the same time, the Cornell Aeronautical Laboratory began developing human augmenters—robots—to enhance the strength of human operators. From 1966 to 1971, General Electric further developed the concept of human augmenters through the Hardiman Project. They can be considered the ancestors of current rehabilitation exoskeleton robots.

Exoskeleton robots usually consist of a power system and sensors that measure the torque of the motor. In addition, some also include sensors that capture biological signals, such as electromyographs (EMG) that measure muscle signals or electroencephalograms (EEG) that allow the brain's electrical signals to be captured and converted into command signals. In addition to the robot shown in the figure above, the medical exoskeleton robots currently available on the market include Lokomat, ReWalk, HAL, Ekso GT, Rex and Indego (Figure AF).

Advantages of exoskeleton robots over traditional walking aids:
1. Safety <br /> In order to ensure that users can use the exoskeleton safely, in addition to the error-proofing control set by the system, there are two safety measures: one is to check the tilt angle and the angular velocity of the user's torso to ensure good center of gravity transmission; the other is to check whether the motor current is greater than the threshold when the swinging leg collides with the ground or is unable to move due to excessive spasms to ensure that there is no muscle strain. In addition, the support part on each leg can be adjusted according to the circumference of the user's lower limbs. This design can effectively avoid skin abrasions when walking with the exoskeleton robot.

2. Save effort

Patients with thoracic spinal cord injuries need to expend a lot of physical energy when wearing KAFOs to stand and walk. In addition, low walking efficiency and slow walking speed are the main factors for the low usage rate of orthoses such as KAFOs. If paraplegic patients want to walk with assistive devices such as forearm crutches, they must rely heavily on their upper limbs to support their body weight while ensuring a smooth center of gravity transfer to maintain balance. This movement pattern is not only inefficient, but may also cause sports injuries due to the large load on the shoulders and wrists. The biggest advantage of exoskeletons over traditional KAFOs is that the motors at the joints provide the joint extension torque required for functional activities. Therefore, users can use a near-normal movement pattern for sitting, standing and walking, rather than a compensatory movement pattern (because this pattern may cause damage to their bodies).

Development prospects

Exoskeleton robots have become a suitable tool to help patients recover. Not only are they easy to use, but they can also provide therapists with objective data to facilitate the formulation of more appropriate training plans, thereby achieving better training results.

In recent years, exoskeletons have developed rapidly, not only with smaller motors, but also with lower noise, smaller size, and higher efficiency. I believe that in the near future, exoskeletons will be smarter and lighter, not only allowing us to walk faster, more steadily, and more flexibly, but also allowing patients to get better treatment results!

(Some pictures in this article are from the Internet)

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