• Advances in robotics research
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• v.2 no.3
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• pp.237-245
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• 2018

This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.5
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• pp.421-426
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• 2015

Need to develop human body's posture supervised robots, gave the push to researchers to think over dexterous design of exoskeleton robots. It requires to develop quantitative techniques to assess human motor function and generate the command to assist in compliance with complex human motion. Upper limb rehabilitation robots, are one of those robots. These robots are used for the rehabilitation of patients having movement disorder due to spinal or brain injuries. One aspect that must be fulfilled by these robots, is to cope with uncertainties due to different patients, without significantly degrading the performance. In this paper, we propose chattering free sliding mode control technique for this purpose. This control technique is not only able to handle matched uncertainties due to different patients but also for unmatched as well. Using this technique, patients feel active assistance as they deviate from the desired trajectory. Proposed methodology is implemented on seven degrees of freedom (DOF) upper limb rehabilitation robot. In this robot, shoulder and elbow joints are powered by electric motors while rest of the joints are kept passive. Due to these active joints, robot is able to move in sagittal plane only while abduction and adduction motion in shoulder joint is kept passive. Exoskeleton performance is evaluated experimentally by a neurologically intact subjects while varying the mass properties. Results show effectiveness of proposed control methodology for the given scenario even having 20 % uncertain parameters in system modeling.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.355-361
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• 2013

Objective: The aim of this study is to investigate the gender-differences in vibrotactile responses(sensitivity and displeasure) of residual forearm simulated by vibration stimulation in upper limb(trans-radial) amputees. Background: Several studies have reported that vibration stimulation using the haptic vibrator is one the most effective methods for delivering sensation to an amputees. However, few studies have reported the perception to haptic vibratory stimulus, particularly sensitivity and displeasure. Method: We set up a custom-made vibration stimulation system that included 6 actuators(3 medial parts and 3 lateral parts) and a graphical user interface(GUI)-based acquisition system to investigate changes in residual somatosensory sensibility and displeasure in the forearm of upper limb(trans-radial) amputees. Vibration actuators were attached at the 25%-point on the proximal forearm. Stimulation with 32Hz, 64Hz, or 149Hz of frequency was used for the sensitivity tests and with 32~257Hz of frequency was used for the discomfort experiments. The subjective responses were evaluated on a 10 point scale. Results: The results showed that vibrotactile sensory perception in male amputees were higher than that in female amputees. In male amputees, the response at lateral area of forearm was the most sensitive than medial area; but, female amputees showed similar sensitive areas. Subjects did not experience any discomfort during vibrotactile stimuli. Conclusion: Vibrotactile response in the amputees was dependent on gender as well as area stimulated by vibration. Application: The results might contribute to develop the vibrotactile feedback system for the amputees.

• PNF and Movement
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• v.15 no.1
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• pp.27-33
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• 2017

Purpose: This study examined the effects of upper- and lower-limb coordinated exercise with proprioceptive neuromuscular facilitation (PNF) on stroke patients' recovery of their balancing and walking abilities. Methods: This study was conducted with 30 patients aged at least 60 years and diagnosed with stroke. The patients were randomly assigned to either a PNF upper- and lower-limb coordinated exercise group of 15 patients or an aero-step balance exercise group of 15 patients. To test the subjects' balancing and walking abilities, balancing ability tests and 10-m walking speed tests were conducted before and after the interventions. The patients performed their respective exercises for 30 minutes per session, three times per week for four weeks. The PNF exercise group performed six stages of exercise consisting of a combination of PNF patterns such as sprinting, skating, and striking. The six stages (right striking, right skating, right sprinting, left striking, left skating, and left sprinting) were performed continuously with a rest period of 1 min. after training for 4 min. The exercises for the aero-step balance group consisted of balancing in a two-leg standing position, weight shifting in a two-leg standing position, one-leg standing, squat exercises, marching in place, and squatting on an aero step. Results: The PNF exercise group showed significant improvements in their balancing ability evaluations compared to the aero-step balance group and also showed significant improvements in their 10-m walking speed tests. Conclusion: Based on the results of this study, PNF upper- and lower-limb coordinated exercise resulted in clinical improvements of stroke patients' balancing and walking abilities. Therefore, this type of exercise is recommended as a clinical intervention for the recovery of stroke patients' lower-limb function. Future studies should be conducted with longer intervention periods and more subjects to generalize the study results.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.15-19
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• 2019

In this study, Theta Gamma Coupling (TGC) analysis was carried out after performing simple and repeated upper limb exercise and comparative experiment to observe changes in the motor cortex of the brain through TGC and to see if mobile rehabilitation therapy is actually effective. As a result, exercise using mobile devices showed higher TGC values in motor cortex as compared with simple repeat upper limb exercise. In addition, paired t-test using SPSS showed statistically significant difference between exercise using mobile devices and simple repeat exercise at P3(t=3.390, df(degree of freedom)=12, p value=0.005). Exercise using mobile devices is effective for rehabilitation because it increases the Theta-Gamma Coupling and activates the motor cortex. Also, since the mobile game contents required the subject to detailed athletic ability adjustment with immersion in the task, it may be thought that brain activation is stronger than simple rehabilitation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.819-825
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• 2010

For rehabilitation of stroke patients the repeat training is needed. However it is difficult to keep up the training for the patients because it is boring. Even if the patients continue the training there is no objective way to evaluate the remedial value. Recently there is a new attempt to apply the haptic system to the rehabilitation of the stroke patients. In this study a haptic system is applied to the rehabilitation of the stroke patients. Through the comparative analysis of the experimental data for the normal people and patients, the validity of the proposed rehabilitation was verified. In conclusion, the patient's condition at 8 days after the experiment has demonstrated the level of ADL.

• Physical Therapy Rehabilitation Science
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• v.8 no.4
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• pp.187-193
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• 2019

Objective: The aim of this preliminary study was to investigate the effects of virtual reality combined with balance training on upper limb function, balance, and activities of daily living (ADL) in persons with acute stroke. Design: Randomized controlled trial. Methods: Fourteen acute stroke survivors were recruited and randomly assigned into two groups: the experimental group (n=7) and the control group (n=7). Both groups performed the conventional rehabilitation therapy for 30 minutes a day, 5 times a week, for 4 weeks. Additionally, the experimental group conducted the virtual reality training for 30 minutes on an unstable surface during each session, whereas the control group performed balance training for 30 minutes on a stable surface. All measurements were performed before and one day after intervention. Upper limb function, balance, and ADL were assessed using the Manual Function Test (MFT), the Berg Balance Scale (BBS), and the Korean version of the Modified Barthel Index (K-MBI), respectively. Results: Both groups showed significant improvements in MFT, BBS, K-MBI after intervention (p<0.05). There were no significant differences between the experimental and control groups with respect to MFT, BBS, and K-MBI after intervention. The experimental group showed a greater decrease in fall risk (BBS<45) after intervention than the control group (p<0.05). Conclusions: These findings suggest that virtual reality combined with balance training has a better effect on balance improvement than virtual reality training alone in persons with acute stroke.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.15-26
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• 2023

In this study, an end-effector robot which is a two-axis delta robot type for upper-limb rehabilitation is designed. It is not only rehabilitation functions that has designed robot but also mechanical and electrical safety devices were constructed to ensure patient safety. By constructing the two-axis delta robot is combined with an LM guide, the operating range and rigidity required for rehabilitation were secured. The electrical safety system which is required for the medical robot was designed, and a safety strategy was established to ensure patient safety and it is applied in the integrated safety circuit. The safety is considered in whole design process from the robot's mechanical design to the electric control unit.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.89.3-89
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• 2001

Recently computer graphic technology has achieved remarkable development. Applications of this technology to various fields are expected. In this study, one application of computer graphics to the medical field is shown. We developed a rehabilitation system of hand manipulation using virtual reality aiming to offer enjoyable rehabilitation training to physically handicapped people with upper limb disabilities. This rehabilitation system generates training environments for upper limbs, such as moving balls in virtual space of computer. And by using data glove as a sophisticated input device, a user can manipulate objects in virtual space by his hand. By using this rehabilitation system, a user can have rehabilitation training under various conditions without feeling tedious.

• PNF and Movement
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• v.13 no.1
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• pp.9-16
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• 2015

Purpose: This study aimed to examined the effects of upper and lower limb coordinated exercise of proprioceptive neuromuscular facilitation (PNF) on static and dynamic balance ability. Methods: The subjects of this study were 18 patients who had been diagnosed with a stroke and hospitalized and who had received rehabilitation treatment at D rehabilitation hospital located in J city. They were randomly and equally assigned to a PNF upper and lower limb coordinated exercise group and an ordinary central nervous system development and treatment group, and they conducted exercises for eight weeks. They carried out exercise three times per week, for 30 minutes per each time. After each four minutes of exercise, each participant was given a and rest for one minute after exercise for four minutes was given. In order to test the subjects' static and dynamic balance ability and their dynamic balance ability, frailty and injuries,: a cooperative studyies of intervention techniques (FICSIT-4) test, a four- step square test (FSST), a timed up and go test (TUG), and a TWT3M tests wasere conducted before and after the exercise. Descriptive statistics were taken for the general characteristics of the subjects, and an independent t-test was conducted both before and after the exercise in order to examine differences between the two groups before and after the exercise were conducted. The A statistical significance level was set at p= 0.05. Results: In all the tests (of FICSIT-4, FSST, TUG, and TWT3M), both the experimental group and the control group saw more improved results, but the experimental group's results were significantly higher than those of the control group, and the size of the effects was larger in the experimental group than in the control group, with statistically significant results. Conclusion: PNF upper and lower limb coordinated exercise applied to chronic stroke patients produced brought significant results in static and dynamic balance ability. PNF and is considered as an important intervention program to improve stroke patients' balance ability.