DIGITAL LIFE

Wearable walking robot allows disabled persons to don it from their wheelchairs

KAIST researchers have unveiled a new wearable robot developed for completely paralyzed persons that can walk to them so that the user can wear it right out of their wheelchairs without the help from others. Also, it was announced that Professor Kyoungchul Kong's team from KAIST will be participating in the wearable robot category of the 3rd Cybathlon, which is being held four years after the team's gold medal win in 2020.

This new version of the wearable robot for paraplegic people, WalkON Suit F1, was developed by Professor Kyoungchul Kong (CEO and founder of Angel Robotics) of KAIST Department of Mechanical Engineering.

WalkON Suit is a wearable robot for people suffering with paraplegic disabilities that the research team has been continuously researching since 2015. This robot assists persons with American Spinal Injury Association (ASIA) Impairment Scale–A (complete paralysis) grade injury, the most severe level of paraplegia. Therefore, its development purpose is different from that of other rehabilitation therapy and muscle strength assisting robots currently being supplied nationally by Angel Robotics.

Professor Kong's research team first announced WalkON Suit 1 in 2016, and then introduced WalkON Suit 4 in 2020, increasing the walking speed to 3.2 km/h, achieving the normal walking speed of people with no disabilities. In addition, it demonstrated the ability to pass through obstacles such as narrow passages, doors, and stairs that can be encountered in daily life.

However, it had the same fundamental problem all wearable robots have, which is that they require the help of others to wear the robot. While a person can walk without help from others once wearing the robot, they needed someone's help to put it on to begin with.

The newly released WalkON Suit F1 presented a technical solution to this fundamental problem. It applied a frontal-docking method instead of a rear-sitting method so that one can wear the robot right away without getting out of a wheelchair and into the robot, which would require help from others mid-transition.

In addition, before wearing the robot, it can walk on its own like a humanoid robot and can approach the user. It also implements a function that actively controls the center of its weight against the pull of gravity so that it maintains balance without falling over even if the user pushes the robot otherwise. The outer design of the WalkON Suit F1, which crosses between a humanoid and a wearable robot, was created by Professor Hyunjoon Park of the Department of Industrial Design at KAIST.

The original function of the wearable robot has also been greatly improved. The performance of the balance control was improved to allow the free use of both hands in upright state, as well as the freedom to take several steps without a cane.

Technological advancements at the components level are also noteworthy. Through close collaboration with Angel Robotics, all core components of the robot, such as the motor, reducer, motor driver, and main circuit, have been domestically produced.

The output density of the motor and reducer modules has been improved by about two folds (based on power per weight) compared to the research team's existing technology, and the control performance of the motor driver has been improved by about three times (based on frequency response speed) compared to the best overseas technology.

In particular, the embedded software technology of the motor driver has been significantly improved so that advanced motion control algorithms can be stably implemented without using expensive higher-level controllers. In addition, visual recognition system for obstacle detection and an AI board for neural network application have been installed.

Professor Kong explained, "WalkON Suit is the culmination of wearable robot technology for the disabled," and added, "The numerous components, control, and module technologies derived from WalkON Suit are setting the standard for the entire wearable robot industry."

Professor Kong's research team revealed WalkON Suit F1 and announced that they will be participating in the 3rd Cybathlon, which is being held after four years since the last event. In this competition, which will be held on October 27, Professor Kong's lab, the Exo Lab will be participating with Jeongsu Park, a Ph.D. Student, as the leader and Seunghwan Kim, the lab's staff researcher with complete paralysis, as the competing athlete.

The difficulty of the missions in this competition has been significantly increased compared to the previous competition, and the number of missions has increased from six to 10. Some missions have been criticized for being overly challenging, going beyond the level that can be encountered in everyday life.

Regarding this, the team leader Jeongsu Park expressed his ambition, saying, "Since we already won first place in the previous competition, our goal in this competition is to show the technological gap rather than competing for rankings."

The Cybathlon is a cyborg Olympics held every four years in Switzerland. This competition will be held in a hybrid format, with some participants taking part in Switzerland while others broadcasting live from stadiums in their own country on October 27. Professor Kong's research team will be participating via live broadcast from the competition facilities installed in Angel Robotics' Advanced Research Institute (Planet Daejeon).

Provided by The Korea Advanced Institute of Science and Technology (KAIST)