I. What is it?
Non-wearable walking aids:
Mainly include smart walking frames, stair climbers, etc. These devices serve as independent external mobile platforms, providing support or transport services to users. Their core advantages lie in providing stable support and strong load-bearing capacity, with lower requirements for the user's muscle strength. However, their flexibility and maneuverability in confined spaces may be limited. Therefore, lightweight and portable wearable exoskeletons are often recommended.
Wearable exoskeletons: These devices are directly attached to the human body, providing assistance by driving joints such as the hips and knees to achieve coordinated "human-machine integration" movement. Their characteristics include flexible movement, adapting to various scenarios such as stairs and flat ground. Examples include Kenqing Technology's "VIGX-π" series, Hypershell's "Hypershell X" exoskeleton walking aid, and Samsung's GEMS Hip.
Figure 1: Kenqing Technology-Π6
Figure 2: Kenqing Technology - Π plus
Figure 3: Hypershell X
Figure 4: Samsung GEMS Hip
II. Working Principle
As we know, climbing stairs is a physically demanding activity for the elderly, requiring a high level of balance. For the intelligent booster to effectively address this problem, its working principle must revolve around two core elements: accurately sensing the user's exertion intention and intelligently adapting to different terrain challenges.
1. Sensing Human Movement Intent
The device's built-in angle sensor captures your leg speed and body posture in real time. When the system detects the start of your steps or push-off movements, it prepares in advance, synchronizing the assist output with your own exertion, achieving a "natural" rather than a rigid push or pull.
2. Identifying Terrain and Anticipating Needs
New generation products, such as the Π6 launched by Kenqing Technology, further integrate environmental sensing cameras. This means that the device can not only "sense" your movements, but also "see" the environment ahead—whether it is flat ground, stairs, or a slope.
The value of terrain recognition is crucial: it allows the device to know in advance what challenges it will face. For example, after recognizing stairs, the system will adjust its assist strategy in advance, providing more timely upward thrust when going upstairs, and switching to auxiliary support and control when going downstairs, greatly improving safety, stability, and comfort in complex terrain. This achieves an intelligent leap from "passive response" to "active adaptation."
III. Core Roles
1. Reducing Metabolic Energy Consumption and Cardiopulmonary Burden
Compared to walking on flat ground, climbing stairs requires significantly higher energy consumption and dynamic stability control. The oxygen consumption during stair climbing is about three times that of walking on flat ground, and it has been clearly listed as one of the most difficult tasks in the daily activities of the elderly [1]. Providing joint assistance for the elderly helps alleviate this burden of "high energy consumption + high instability." The joint torque curve in the figure below also shows a significant increase in the knee joint, further indicating that the elderly need assistance when going up and down stairs [1].
Figure 5 Joint torque curve
2. Improve gait, balance and physical function, and reduce sedentary time
A modular hip exoskeleton training study for community-dwelling older adults (≥65 years) showed that after 12 sessions of exoskeleton gait training, each lasting 30 minutes, participants showed “clinically significant improvements” in walking speed, balance and endurance. Two of the older adults who originally had a walking speed < 1.0 m/s (considered a high risk threshold for falls) had a walking speed exceeding 1.0 m/s after the intervention. At the same time, sedentary time was significantly reduced, and the training process was safe and well tolerated [2].
3. Precisely Compensating for Joint "Power Deficiency" Elderly people generally experience "power deficiency" when going up and down stairs, requiring exoskeletons to supplement joint power during critical phases. Studies have found that if exoskeletons can provide a small amount of torque (e.g., around 0.2 N·m/kg) during knee extension (going up and down stairs) and ankle plantar flexion (especially downstairs), they can effectively compensate for the power deficit in the elderly, improving the safety and efficiency of climbing stairs [1].
4. Reducing Muscle Fatigue and Burden: Multiple studies on hip exoskeletons and soft exoskeletons have shown that appropriate hip joint assistance can reduce the electromyographic activity level of major lower limb muscles (such as rectus femoris and gluteus medius) during walking on flat ground, going uphill, or climbing stairs, thereby reducing muscle fatigue [3].
IV. Safety Verification
1. Real-time Fall Detection and Early Warning
The device utilizes a high-sensitivity IMU combined with a self-developed real-time posture analysis algorithm to identify falls when the body loses balance. It issues an audible warning and automatically limits joint assist, giving the user time to adjust. Kenqing Technology's Π6 product integrates a camera to provide additional environmental context information, enhancing its ability to predict risks such as tripping and missteps.
2. Battery Safety Design
The Π6's "one-button battery disconnection" design is a crucial safety redundancy: in extreme situations (such as device malfunction requiring rapid disconnection), the user or guardian can instantly disconnect the battery from the main unit, immediately cutting off all power output and ensuring safety. This complements the purely software-based safety strategy, providing hardware-level safety assurance.
References
[1] Böhme M, Weiske F, Jäkel J, Zentner J, Witt M. Evaluation of the power deficit of elderly people during stair: Which joints should be assisted at least by an exoskeleton and with what amount? Wearable Technol. 2022 Mar 25;3:e4. doi: 10.1017/wtc.2022.1. PMID: negotiation 38486914; PMCID: PMC10936312.
[2] Jayaraman et al. Research on the impact of modular hip exoskeleton GEMS training on elderly people in the community [J]. Related journals, 2022. https://pmc.ncbi.nlm.nih.gov/articles/PMC9801566/.
[3] Young AJ, Ferris DP. State of the Art and Future Directions for Lower Limb Robotic Exoskeletons. IEEE Trans Neural Syst Rehabil Eng. 2017 Feb;25(2):171-182. doi: 10.1109/TNSRE.2016.2521160. Epub 2016 Jan 27. PMID: 26829794.
