Jeong Hoon Lim

A soft exoskeleton for hand assistive and rehabilitation application using pneumatic actuators with variable stiffness

In this paper, we present the design of a soft wearable exoskeleton that comprises of a glove embedded with pneumatic actuators of variable stiffness for hand assistive and rehabilitation application. The device is lightweight and easily wearable due to the usage of soft pneumatic actuators. A key feature of the device is the variable stiffness of the actuators at different localities that not only conform to the finger profile during actuation, but also provides customizability for different hand dimensions. The actuators can achieve different bending profiles with variable stiffness implemented at different localities. Therefore, the device is able to perform different hand therapy exercises such as full fist, straight fist, hook fist and table top. The device was characterized in terms of its range of motion and maximum force output. Experiments were conducted to examine the differences between active and passive actuation. The results showed that the device could achieve hand grasping and pinching with acceptable range of motion and force.

A fabric-regulated soft robotic glove with user intent detection using EMG and RFID for hand assistive application

This paper presents a soft robotic glove designed to assist individuals with functional grasp pathologies in performing activities of daily living. The glove utilizes soft fabric-regulated pneumatic actuators that are low-profile and require lower pressure than previously developed actuators. They are able to support fingers and thumb motions during hand closure. Upon pressurization, the actuators are able to generate sufficient force to assist in hand closing and grasping during different manipulation tasks. In this work, experiments were conducted to evaluate the performances of the actuators as well as the glove in terms of its kinetic and kinematic assistance on a healthy participant. Additionally, surface electromyography and radio-frequency identification techniques were adopted to detect user intent to activate or deactivate the glove. Lastly, we present preliminary results of a healthy participant performing different manipulation tasks with the soft robotic glove controlled by surface electromyography and radio-frequency identification techniques.

A Magnetic Resonance Compatible Soft Wearable Robotic Glove for Hand Rehabilitation and Brain Imaging

In this paper, we present the design, fabrication and evaluation of a soft wearable robotic glove, which can be used with functional Magnetic Resonance imaging (fMRI) during the hand rehabilitation and task specific training. The soft wearable robotic glove, called MR-Glove, consists of two major components: a) a set of soft pneumatic actuators and b) a glove. The soft pneumatic actuators, which are made of silicone elastomers, generate bending motion and actuate finger joints upon pressurization. The device is MR-compatible as it contains no ferromagnetic materials and operates pneumatically. Our results show that the device did not cause artifacts to fMRI images during hand rehabilitation and task-specific exercises. This study demonstrated the possibility of using fMRI and MR-compatible soft wearable robotic device to study brain activities and motor performances during hand rehabilitation, and to unravel the functional effects of rehabilitation robotics on brain stimulation.

Characterisation and evaluation of soft elastomeric actuators for hand assistive and rehabilitation applications.

Abstract Various hand exoskeletons have been proposed for the purposes of providing assistance in activities of daily living and rehabilitation exercises. However, traditional exoskeletons are made of rigid components that impede the natural movement of joints and cause discomfort to the user. This paper evaluated a soft wearable exoskeleton using soft elastomeric actuators. The actuators could generate the desired actuation of the finger joints with a simple design. The actuators were characterised in terms of their radius of curvature and force output during actuation. Additionally, the device was evaluated on five healthy subjects in terms of its assisted finger joint range of motion. Results demonstrated that the subjects were able to perform the grasping actions with the assistance of the device and the range of motion of individual finger joints varied from subject to subject. This work evaluated the performance of a soft wearable exoskeleton and highlighted the importance of customisability of the device. It demonstrated the possibility of replacing traditional rigid exoskeletons with soft exoskeletons that are more wearable and customisable.

MRC-glove: A fMRI compatible soft robotic glove for hand rehabilitation application

In this paper, we present the design, fabrication and preliminary evaluation of a soft robotic glove which can be used with functional Magnetic Resonance imaging (fMRI) during the hand continuous passive motion (CPM) in rehabilitation. The device comprises of two major components: a) soft pneumatic actuators and b) a glove. The soft pneumatic actuators, which are made of silicon elastomers, generate a bending motion and actuate the finger joints upon pressurization. As the device contains no ferromagnetic materials and operates pneumatically, we hypothesize that the device is MR-compatible. Our results show that the device did not cause artifacts to the fMRI images during CPM. This study demonstrated the possibility of using fMRI and MR-compatible soft robotic glove (MRC-Glove) to study motor performances of the brain during CPM rehabilitation and unravel the effects of rehabilitation robotics on brain stimulation.

Design of a Soft Robotic Glove for Hand Rehabilitation of Stroke Patients With Clenched Fist Deformity Using Inflatable Plastic Actuators

In this paper, we present a soft robotic glove designed to augment hand rehabilitation for stroke patients with clenched fist deformity. The robotic glove provides active finger extension for hand rehabilitative training, through its embedded inflatable actuators that are fabricated by heat bonding of flexible plastic sheets. Upon pressurization, the actuators inflate, stiffen, and extend the fingers. The actuators were embedded in the finger pockets of a glove. In this work, the device was evaluated in terms of its extension torque on a hand model, a healthy subject and a stroke patient. Preliminary results showed that the device was able to generate significant torques to provide assistance in finger extension and hand opening on both healthy and stroke participants.

Development of a Soft Pneumatic Sock for Robot-Assisted Ankle Exercise

Deep vein thrombosis (DVT) is a severe medical condition that affects many patients around the world, where one of the main causes is commonly associated with prolonged immobilization. Current mechanical prophylaxis systems, such as the compression stockings and intermittent pneumatic compression devices, have yet to show strong efficacy in preventing DVT. The current study aimed to develop a soft pneumatic sock prototype that uses soft extension pneumatic actuators to provide assisted ankle dorsiflexion–plantarflexion motion, so as to prevent the occurrence of DVT. The prototype was evaluated for its efficacy to provide the required dorsiflexion–plantarflexion motion by donning and actuating the prototype on simulated ankle–foot models with various ankle joint stiffness values. Our results showed that the soft extension actuators in the sock prototype provided controllable assisted ankle plantarflexion through actuator extension and ankle dorsiflexion through actuator contraction, where in our study, the actuations extended to 129.9–146.8% of its original length. Furthermore, the sock was able to achieve consistent range of motion at the simulated ankle joint across different joint stiffness values (range of motion: 27.5 ± 6.0 deg). This study demonstrated the feasibility of using soft extension pneumatic actuators to provide robot-assisted ankle dorsiflexion–plantarflexion motion, which will act as an adjunct to physiotherapists to optimize therapy time for bedridden patients and therefore may reduce the risk of developing DVT.

Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors

Various robotic exoskeletons have been proposed for hand function assistance during activities of daily living (ADL) of stroke survivors. However, traditional exoskeletons involve the use of complex rigid systems that impede the natural movement of joints, and thus reduce the wearability and cause discomfort to the user. The objective of this paper is to design and evaluate a soft robotic glove that is able to provide hand function assistance using fabric-reinforced soft pneumatic actuators. These actuators are made of silicone rubber which has an elastic modulus similar to human tissues. Thus, they are intrinsically soft and compliant. Upon air pressurization, they are able to support finger range of motion (ROM) and generate the desired actuation of the finger joints. In this work, the soft actuators were characterized in terms of their blocked tip force, normal and frictional grip force outputs. Combining the soft actuators and flexible textile materials, a soft robotic glove was developed for grasping assistance during ADL for stroke survivors. The glove was evaluated on five healthy participants for its assisted ROM and grip strength. Pilot test was performed in two stroke survivors to evaluate the efficacy of the glove in assisting functional grasping activities. Our results demonstrated that the actuators designed in this study could generate desired force output at a low air pressure. The glove had a high kinematic transparency and did not affect the active ROM of the finger joints when it was being worn by the participants. With the assistance of the glove, the participants were able to perform grasping actions with sufficient assisted ROM and grip strength, without any voluntary effort. Additionally, pilot test on stroke survivors demonstrated that the patients grasping performance improved with the presence and assistance of the glove. Patient feedback questionnaires also showed high level of patient satisfaction and comfort. In conclusion, this paper has demonstrated the possibility of using soft wearable exoskeletons that are more wearable, lightweight, and suitable to be used on a daily basis for hand function assistance of stroke survivors during activities of daily living.

Study on the use of soft ankle-foot exoskeleton for alternative mechanical prophylaxis of deep vein thrombosis

Deep vein thrombosis (DVT) is a severe medical condition that can affect patients who are long-term bed-ridden, due to diseases such as stroke. Current prevention methods for DVT focus on either pharmacological prophylaxis or mechanical prophylaxis, where current mechanical prophylaxis systems that target prevention of DVT have limited success rates as patients are still susceptible to occurrences of DVT even with long-term usage of such systems. Therefore, this paper sought to present the design of a soft robotic exosock using soft pneumatic actuators to assist in passive ankle exercises for the prevention of DVT and to conduct a preliminary study on healthy human subjects to evaluate the effectiveness of this device in assisting ankle motion in terms of the range of motion assisted on the ankle. Our findings indicated that the exosock was able to provide assisted ankle plantarflexion-dorsiflexion to the subjects. Furthermore, our results showed that we were able to achieve an average of 16.4±1.3° of dorsiflexion from a resting position of the ankle with an average error of 2.7±1.4° in the real-time feedback of the ankle through a joint measurement unit. Therefore, the soft robotic exosock can potentially be used in the clinical rehabilitation of bedridden patients to prevent DVT while allowing for real-time feedback of the ankle off site.

A Fully Fabric-Based Bidirectional Soft Robotic Glove for Assistance and Rehabilitation of Hand Impaired Patients

This letter presents a fully fabric-based bidirectional soft robotic glove designed to assist hand impaired patients in rehabilitation exercises and performing activities of daily living. The glove provides both active finger flexion and extension for hand assistance and rehabilitative training, through its embedded fabric-based actuators that are fabricated by heat press and ultrasonic welding of flexible thermoplastic polyurethane-coated fabrics. Compared to previous developed elastomeric-based actuators, the actuators are able to achieve smaller bend radius and generate sufficient force and torque to assist in both finger flexion and extension at lower air pressure. In this letter, experiments were conducted to characterize the performances of the glove in terms of its kinematic and grip strength assistances on five healthy participants. Additionally, we present a graphical-user interface that allows user to choose the desired rehabilitation exercises and control modes, which include button-controlled-assistive mode, cyclic movement training, intention-driven task-specific training, and bilateral rehabilitation training.