Comparing the Effects of Admittance and Error-based Control of a Trunk Rehabilitation Robot on the User’s Balance

Hosu Lee,Amre Eizad,Junyeong Lee,Yunho Choi,Won-Kyung Song,Kyung-Joong Kim,Jungwon Yoon 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11

Trunk training is an important part of the rehabilitation of people suffering from the physical effects of brain lesions caused by diseases such as stroke, as it can help improve their static and dynamic balance, while also helping to improve gait performance. In order to facilitate trunk rehabilitation and reduce therapist workload, we have developed a trunk rehabilitation robot (TRR) that can provide tunable quantitative training with the option to include sensory augmentation through various bio-feedback, in order to implement a large variety of trunk training protocols. In this paper, we have developed an error-based controller to generate the unstable seat condition using the TRR. In order to verify the feasibility of this controller, we have carried out tests with 20 young healthy subjects and compared its performance with the existing admittance controller in terms of seat movement parameters and center of pressure and trunk movement based balance parameters. The results show that although there is no statistically significant difference between the controllers in terms of the balance measures, use of the error-based controller results in lesser amount of seat movement, which may make it more comfortable for the user. However, the participants had a difference of opinion about which controller they felt to be more comfortable and easier to use.

Development of a Six Bar Mechanism Based Active Knee Orthosis for Post-Stroke Gait Rehabilitation

Hosu Lee,Amre Eizad,Sanghun Pyo,Hoyoung Kim,Junyeoung Lee,Jungwon Yoon 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

An active knee orthosis can support a patient’s weight and assist the knee during stance phase for improved gait assistance. This paper presents the development of a lightweight active knee orthosis (AKO) for post-stroke gait rehabilitation that is capable of providing assistive torque in a pattern that is similar to the natural pattern of the human leg. The proposed system is designed to be lightweight and comfortable to use. The system utilizes a single series elastic actuator and is controlled using the patient-driven motion reinforcement (PDMR) control to provide assistive torque to the user’s knee based on the force information gathered from its series elastic link. A pilot study was performed with one young healthy subject wearing an ankle weight (4 kg) on one leg, in order to identify the effects and potential implications of using the AKO for gait assistance of hemiplegic subjects. No discomfort was reported by the participant during the gait trials. Addition of the ankle weight reduced the knee movements, gait speed and gait balance, while increasing the knee range of motion asymmetry. While using the AKO, the subject was able to overcome much of the detrimental effects of the ankle weight and show improvements in majority of the outcome measures. Thus, the developed AKO exhibited promising outcomes in this pilot study that warrant further studies to better understand the implications of using this system during gait rehabilitation of stroke survivors.

Development of Haptic Bracelets Based Arm Swing Feedback System for Stroke Survivors

Hosu Lee,Amre Eizad,Geonhyup Lee,Yeongmi Kim,Jungwon Yoon 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

For stroke survivors, the ultimate goal of rehabilitation training for community life is to increase the dynamic stability, which can be helped by increasing the walking speed or symmetry. Several researches have reported the use of haptic stimulation to increase the dynamic stability of gait. Haptic systems have many advantages such as, portability and low-cost, that make them extremely suited for rehabilitation applications. However, until now the use of these systems has been focused mainly on the lower limbs. Gait is a harmonic motion that includes both the upper and lower limbs. A study with people suffering from Parkinson’s Disease showed that it is possible to bring about spatiotemporal gait changes using an arm swing cueing device. Therefore, in this paper, we present the development and verification of a haptic bracelet designed to deliver arm swing based haptic feedback for the rehabilitation of stroke survivors. The presented system is portable, composed of inexpensive sensors and it can measure the arm swing angle correctly regardless of the location or direction of the sensor. The measurements made using the developed system were compared to those made using a standard motion tracking system and only an acceptable amount of error was found. The developed system may be used to characterize the effect of upper extremity motion modification during gait. It may also be used as a system for improving gait speed and symmetry of stroke patients using haptic vibration feedback.

Design of a Haptic Walker system based on cable driven actuator for Lower Limb Rehabilitation

Hosu Lee,Muhammad Raheel Afzal,Jungwon Yoon 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

In recent years, several robotic devices have been developed for lower limb rehabilitation. However, the post-training functional improvements in gait abilities after using those devices are reported to be either similar to conventional rehabilitation therapy or even lower in some cases. Meanwhile, those existing devices have several drawbacks such as heavy, complex mechanisms, expensive, restriction of mobility. Thus, this paper suggests a system which can help to realize lower limb joint torque on real ground without restriction of mobility. A walker combined with wire driven actuation of lower limb is proposed. The advantages of the proposed system are that the system is lightweight, easy to wear, can be implemented with simplistic control scheme and provides walking experience on the actual ground. In this paper, we have presented the design of the proposed device and performed analysis of its dynamics by using ADAMS® to assess its actuation. In future work the optimization of the design and fabrication of the system will be carried out.

Effects of using TENS as Electro-tactile Feedback for Postural Balance under Muscle Fatigue Condition

Junyeong Lee,Hosu Lee,Amre Eizad,Jungwon Yoon 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

Impaired postural control following muscle fatigue (MF) can result in falling, which can lead to fracture or other trauma. Transcutaneous electrical nerve stimulation (TENS) can reduce the muscle weakness that occurs due toMF and electro-tactile feedback can help guide the user to achieve postural or movement goals by providing sensory augmentation. The aim of the presented work is to evaluate experimentally the concept that these two effects can be applied simultaneously through the use of TENS as electro-tactile feedback. In this proof-of-concept study, two healthy participants stood in the one-leg stance while in MF condition for 30 seconds under ‘No TENS’, ‘TENS Continuous’ and ‘TENS Feedback’ conditions. Their medio-lateral trunk tilt was recorded during all trials. Electro-tactile feedback was achieved by modulating TENS intensity according to body sway in the medio-lateral direction. The results show that, as compared to the No TENS condition, there was no substantial improvement in postural stability under the TENS Continuous condition. However, the TENS Feedback condition resulted in the highest level of postural stability. Due to the small sample group in this pilot study, it is not possible to conclusively prove the benefits of using TENS as a feedback modality. However, results of both the male and female participants suggest that TENS may hold promise for use as a new electro-tactile biofeedback modality for postural improvement with the added benefit of alleviating the effects of muscle fatigue. In the future, studies with larger sample groups will be undertaken to demonstrate clearly the benefits of using TENS as electro-tactile biofeedback.

보행 재활용 케이블 구동 로봇 설계

이호수(HoSu Lee),가셈 아바스네자드(Ghasem Abbasnejad),소헤일 가라타페(Soheil Gharatappeh),윤정원(JungWon Yoon) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.4

옴니 풀리 기반 전방향 트레드밀 개발

이호수(Hosu Lee),표상훈(Sanghun Pyo),박상준(Sangjoon Park),윤정원(Jungwon Yoon) 제어로봇시스템학회 2017 제어·로봇·시스템학회 논문지 Vol.23 No.7

Locomotion interface with a virtual reality environment can enhance immersiveness of a user due to the increased proprioception and real energy consumption. An Omni-Directional Treadmill (ODT) is considered as one of these devices; it can facilitate human movements such as walking, running and turning. It can provide a two-dimensional locomotion interface function for interacting an avatar in the virtual environment and the user in the real environment. Existing Omni-directional treadmills are heavy, complex and exhibit low power transmission efficiency. Besides, their significant limitation is slow acceleration and deceleration; which makes them inadequate for applications such as gaming and training of soldiers in virtual environment. Therefore, this paper suggests a novel design of a Fast Omni-Directional Treadmill (F-ODT). The proposed system is simpler, lightweight and produces a high power transmission efficiency based on the suggested Omni-pulley mechanism. Dynamic analysis of the design is performed using simulation program ADAMS® to calculate the drive power, and the required drive motor are selected accordingly. Furthermore, prototype of the F-ODT system is developed according to the proposed design and the capability of the system to provide rapid acceleration is validated. The proposed F-ODT system will be used as a locomotion interface platform in various virtual reality environments such as training of soldiers, gaming, educational experiences and gait rehabilitation. Future task is integration of the F-ODT with a motion capture system and a display system for immersive virtual reality experience.

전방향 트레드밀 장치 설계

이호수(HoSu Lee),박상준(SangJun Park),윤정원(JungWon Yoon) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.4

Seedling Growth and Flowering of Korean Endemic Coreanomecon hylomeconoides as Affected by Light Intensity and Nutrient Solution

Seung Youn Lee,Hosu Ha,Ki Sun Kim 한국원예학회 2015 한국원예학회 학술발표요지 Vol.2015 No.10

보행 보조용 차동 케이블 구동기 기반 능동형 무릎 보장구 설계

김호영(Hoyoung Kim),이호수(Hosu Lee),아믈 에이자드(Amre Eizad),윤정원(Jungwon Yoon) 한국HCI학회 2021 한국HCI학회 학술대회 Vol.2021 No.1

기존 하지 재활을 위해 개발된 로봇들은 환자들이 보행훈련을 하기에 비용이 높아 실제로 접근하기 어렵고, 계단 및 지면 보행훈련을 제공하는데 한계를 지닌다. 계단 및 지면 보행훈련이 가능한 능동형 무릎 보장구는 기존 개발된 여러 장치에서 무게 및 비용에서 여전히 한계점이 있다. 만성 뇌병변 환자가 실제 보행훈련시 무리가 없게 하기 위해서는 먼저 무게를 가볍게 만드는 것이 중요하고, 역구동성(Backdrivability)을 갖춤으로써 기구를 착용한 상태에서 구동부의 관성력에 의한 불편함을 느끼지 않는 것이 중요하다. 이를 위해 본 논문에서는 차동 케이블 구동기(Differential Cable Drive) 기반의 능동형 무릎 보장구를 제안한다. 제안하는 시스템은 차동 도르래 원리를 기반으로 높은 기어비를 낼 수 있는 동시에 높은 역구동성을 가질 수 있다. 또한, 초기 장력을 조절함에 따라 구동 토크의 크기를 증감시킬 수 있어 낮은 모터의 동력으로도 보행에서 필요한 토크를 낼 수 있다. 위와 같은 장점으로 인해, 시스템의 전체 무게를 줄일 수 있으며, 역구동성으로 인해 보행 보조에 있어서도 높은 효율을 낼 수 있다. 본 연구에서는 무릎 보장구의 최적 설계 이후 동적 해석을 진행하였으며, 3D 모델링을 통해 구동부 시제품을 제작하였다.