Three Breakthroughs in Six Decades: The Path Forward for Next-Generation Rehabilitation Robots

The more economically developed a region is, the faster its rehabilitation industry develops.

This is because, with the improvement in living standards, residents have become more health-conscious and have gained a clearer understanding of rehabilitation medicine.

The paper “Nursing Coordination in Rehabilitation Therapy for Stroke,” published by Wang Yang and Hou Yuhua from Jiaozhou Central Hospital in Qingdao, Shandong Province, shows that among stroke patients who received rehabilitation therapy, 90% were able to perform activities of daily living independently, and 30% were capable of performing light-duty work. In contrast, among stroke patients who did not receive rehabilitation therapy, only 6% were able to perform activities of daily living independently, and merely 5% were capable of performing light-duty work.

This study demonstrates that rehabilitation therapy plays a significant role in helping patients restore normal daily functioning and reintegrate into society.

Based on its vast population data, China is considered the country with the largest rehabilitation needs globally. According to statistical data from The Lancet, the number of people in China requiring rehabilitation services reached 460 million in 2019. For instance, there are approximately 13 million stroke patients in China, and the total number of people with disabilities stands at around 85.02 million, including 24.72 million with physical disabilities.

The immense patient demand has given rise to a vast rehabilitation market. With the accelerating pace of population aging, heightened public awareness of rehabilitation, and strong policy support from the government, the market size of the rehabilitation medical services industry is poised for sustained growth.

The "2019 Research Report on the Development Potential of the Rehabilitation Industry" released by VCBeat shows that in 2018, the market size of China's rehabilitation medical industry reached RMB 45 billion, and is expected to reach RMB 103.3 billion by 2022, with a compound annual growth rate (CAGR) of 23% from 2018 to 2022.

Meanwhile, VCBeat Research Institute also conducted a comprehensive evaluation of the development potential in various sub-sectors of the rehabilitation industry, identifying rehabilitation robotics, tele-rehabilitation, rehabilitation informatics, musculoskeletal rehabilitation, rehabilitation nursing, and cardiopulmonary rehabilitation as the six major high-potential sectors for the future.

The rehabilitation industry has a bright future, but the path is fraught with challenges. On one hand, China’s rehabilitation sector faces critical pain points, including a shortage of rehabilitation institutions and physicians, as well as uneven competency levels among rehabilitation therapists. On the other hand, traditional exoskeleton rehabilitation robots, designed to address these issues, have certain limitations.

In fact, the exoskeleton is a device developed by the U.S. military in the 1960s specifically to enhance individual combat capabilities. Around 1960, General Electric Company and the Defense Advanced Research Projects Agency (DARPA) of the United States jointly developed an exoskeleton device named Hardiman. This device could amplify the wearer’s strength by 25 times; however, it was bulky, weighed 680 kg, suffered from inadequate power supply, and lacked sufficient endurance for prolonged operation.

With advancements in sensors, computers, and other technologies, countries such as the United States, the United Kingdom, and Canada intensified their research on exoskeleton devices in the 1980s. Meanwhile, some research teams began exploring the application of exoskeleton technology in the field of medical rehabilitation, leveraging its capabilities to support the human body and facilitate movement. Statistics show that by the early 1990s, there were at least 56 exoskeleton rehabilitation robotics research centers worldwide.

Publicly available information indicates that traditional exoskeleton robots can assist patients with paraplegia and other conditions in regaining the ability to perform actions such as standing, walking, and turning through traction and support. Additionally, they can facilitate certain rehabilitation training exercises for patients.

For example, patients with conditions such as stroke and hemiplegia may experience a flaccid paralysis phase lasting 1–2 weeks in the early stages; the longer this period of flaccidity persists, the poorer the functional recovery. Passive movement training using traditional exoskeleton rehabilitation robots helps restore limb function, accelerate the rehabilitation process, and improve prognostic outcomes.

Additionally, for certain patients, such as those who are bedridden for prolonged periods, traditional exoskeleton rehabilitation robots can help stretch their muscles and delay muscle atrophy.

However, traditional exoskeleton rehabilitation robots, which are based on military exoskeletons, have significant value in assisting patients with paraplegia and other conditions, but they have obvious limitations when used for rehabilitation treatment.

First, traditional exoskeleton rehabilitation robots provide passive training, which yields poorer rehabilitation outcomes compared to active training.. In the field of rehabilitation, there is a consensus in the medical community that active patient training yields greater clinical benefits than passive stretching exercises.

Passive training refers to assisting patients in moving along predetermined trajectories through methods such as stretching their limbs. Active training, by contrast, involves facilitating limb movement in response to neural signals generated by the patient’s brain, with the aim of重塑ing the connections between the limbs and the central nervous system to restore motor function.

Traditional exoskeleton rehabilitation robots assist patients in performing movements such as standing, walking, and turning through traction and support; however, they do not facilitate active training. Consequently, their rehabilitative efficacy is significantly limited.

Secondly, traditional exoskeleton rehabilitation robots are relatively bulky and cumbersome, and their operation is also complex.. For example, some traditional exoskeleton rehabilitation robots require therapists to undergo approximately one week of training, followed by multiple patient training sessions, before they can be used under therapist supervision.

Finally, the human lower limbs have seven degrees of freedom, but the degrees of freedom of traditional exoskeleton rehabilitation robots cannot meet patient needs.. For example, a sit-to-stand exoskeleton rehabilitation robot developed by an institution has three degrees of freedom in each lower limb.

Overall, traditional exoskeleton rehabilitation robots can assist patients with paraplegia in walking and movement, but further optimization and breakthroughs are needed for their application in rehabilitative therapy.

Given the limitations of traditional exoskeleton rehabilitation robots in the field of rehabilitation, there is a general consensus within the industry on the need to develop next-generation rehabilitation robots.

For next-generation rehabilitation robots, Dr. Ding Ye believes they should possess the following three characteristics:

First, next-generation rehabilitation robots need to be lighter and more portable, making them easier for patients to wear and operate. With such lightweight devices, patients can don the equipment independently without assistance from rehabilitation therapists and conduct active rehabilitation training on their own.

Second, next-generation rehabilitation robots must be more intelligent, enabling them to better understand patients’ movement intentions and cognitive states. Their level of intelligence should reach the capacity to provide necessary support to patients at specific times and under specific circumstances. Meanwhile, intelligent rehabilitation robots must also deliver personalized, customized rehabilitation services tailored to individual patients and adapt to diverse rehabilitation environments, such as public squares, stairwells, and rehabilitation rooms.

Third, next-generation rehabilitation robots must be more precise. Algorithms enable robots to better understand patients' movement intentions, while precision ensures that robots can provide accurate assistance during human-robot interaction. For instance, if a patient's quadriceps muscles require 3 N of force one second into leg lifting, the robot should deliver exactly 3 N of force to the quadriceps at that same time point.

Easier said than done. To develop next-generation rehabilitation robots, companies must achieve breakthroughs in materials, structural design, and algorithms, among other areas.

In terms of materials, traditional exoskeleton rehabilitation robots are relatively bulky, causing inconvenience for patients in wearing them and for therapists in operating them. In response, Dr. Ding Ye stated, “Rehabilitation robotics companies need to explore new materials to ensure that products are lighter while maintaining adequate support.”

In terms of hardware architecture, rehabilitation robotics companies need to design an overall structure that is more convenient and effortless for patients to wear. This structure must incorporate new materials, new actuators, and new algorithms to achieve comprehensive optimization of the rehabilitation robot. Furthermore, the hardware architecture must align with the value proposition of the rehabilitation robot.

Dr. Ding Ye stated, “The value of lower-limb rehabilitation robots lies in rehabilitation; therefore, the indicated patients should be those with a certain degree of muscle strength and rehabilitation needs, rather than patients with conditions such as paraplegia. Based on this, the structure of lower-limb rehabilitation robots should not follow the traditional design that supports the patient’s entire body weight, but should instead feature corresponding innovations focused on their rehabilitative value.”

In terms of actuators, rehabilitation robotics companies need to achieve breakthroughs that increase power density, enabling lighter and more compact actuators to deliver greater energy output.

Algorithmically, rehabilitation robots need to consider how to better perceive users' behavioral patterns and movement intentions.

Dr. Ding Ye stated, “Yuanye Technology’s independently developed intelligent muscle exoskeleton was designed from the outset with next-generation robotics in mind. As the world’s first intelligent muscle exoskeleton, it features lightweight comfort, intelligent customization, and precise assistance.”

To enable physicians and patients to gain an in-depth understanding of intelligent muscle exoskeletons and next-generation rehabilitation robots, YuanYe Technology will hold the launch event for the world’s first muscle exoskeleton on July 16, 2022.

At that time, key leaders from the Suzhou Industrial Park Administrative Committee invited by YuanYe Tech, investors from renowned institutions such as Hillhouse Ventures, Country Garden Ventures, Linear Capital, and Qiaobei Capital, as well as top domestic experts in the field of rehabilitation, will jointly discuss the application and future of intelligent muscle exoskeletons.