Jeongsoo Lee

Development of a finger motion measurement system using linear potentiometers

In this paper, a wearable sensing glove for measuring motion of fingers is proposed. The proposed system consists of linear potentiometers, flexible wires and linear springs, which make the whole system compact and light not to interfere with the natural finger motion. Inspired by the wrinkles of the finger joints are smoothed when the finger is flexed, a flexible wire is attached on the back of the finger. As the flexible wire is moved by the finger motion, the joint angles are calculated by measuring the length change of the flexible wire. A linear potentiometer with a linear spring for maintaining wire tension is applied to measure the joint angle. Because the motion of the proximal interphalangeal (PIP) is dependent on the distal interphalangeal (DIP) joint, only two linear potentiometers are applied for each finger. A compact sensing module including ten linear potentiometers and springs is attached on a glove. By simply wearing the sensing glove, the finger motions can be easily measured with an intuitive program interface.

Design of a hand exoskeleton for biomechanical analysis of the stroke hand

In this paper, the design of a hand exoskeleton system is introduced for biomechanical analysis of the stroke hand. In order to diagnose the status of the stroke hand, muscular forces associated with the finger movement need to be be estimated. The muscular forces can be estimated by a biomechanical model using moment equilibrium around finger joints, thus the required information for the moment equilibrium such as finger joint angles and external forces should be measured and applied. In this paper, a hand exoskeleton system, which can 1) measure the finger joint angles using a four-bar linkage based exoskeleton structure, and 2) apply and measure normal forces to the fingers, is designed. The performance of this design was verified by simulation and experiments with a manufactured prototype.

Design of a wearable hand exoskeleton for exercising flexion/extension of the fingers

In this paper, design of a wearable hand exoskeleton system for exercising flexion/extension of the fingers, is proposed. The exoskeleton was designed with a simple and wearable structure to aid finger motions in 1 degree of freedom (DOF). A hand grasping experiment by fully-abled people was performed to investigate general hand flexion/extension motions and the polynomial curve of general hand motions was obtained. To customize the hand exoskeleton for the user, the polynomial curve was adjusted to the joint range of motion (ROM) of the user and the optimal design of the exoskeleton structure was obtained using the optimization algorithm. A prototype divided into two parts (one part for the thumb, the other for rest fingers) was actuated by only two linear motors for compact size and light weight.

Analysis of Finger Muscular Forces using a Wearable Hand Exoskeleton System

In this paper, the finger muscular forces were estimated and analyzed through the application of inverse dynamics-based static optimization, and a hand exoskeleton system was designed to pull the fingers and measure the dynamics of the hand. To solve the static optimization, a muscular model of the hand flexors was derived. The experimental protocol was devised to analyze finger flexors in order to evaluate spasticity of the clenched fingers; muscular forces were estimated while the flexed fingers were extended by the exoskeleton with external loads applied. To measure the finger joint angles, the hand exoskeleton system was designed using four-bar linkage structure and potentiometers. In addition, the external loads to the fingertips were generated by cable driven actuators and simultaneously measured by loadcells which were located at each phalanx. The experiments were performed with a normal person and the muscular forces estimation results were discussed with reference to the physical phenomena.

Design of a wearable hand rehabilitation system for quantitative evaluation of the stroke hand

In this paper, the design of a hand rehabilitation system is introduced for evaluating the hand function and performing the hand rehabilitation. In an attempt to evaluate the hand function such as a finger stiffness, a finger independency, a multi-finger synergy quantitatively, the finger joint angles and the external force to the finger should be measured via the device. In addition, the device assists voluntary/involuntary movement of the hand flexion/extension motion for hand rehabilitation and the device can apply the force to each finger. In order to find the additional requirements, an experts group interview was performed. According to the interview, several requirements for designing the rehabilitation system were found and these are categorized as four parts (wearability, durability, soft contacting with skin and stability). Based on the above requirements, several structure design candidates are introduced and analyzed for each candidates merits and demerits with numerical simulation. Total system configuration using the final design and future works are introduced in the last part of this paper.

Development of a dance rehabilitation system using kinect and a vibration feedback glove

In this paper, a dance rehabilitation system using Kinect and a vibration feedback glove is proposed. The proposed system provides enjoyable and fun rehabilitation treatment by combining a markerless motion capture system, vibration feedback, and dance music. This system shows a sequence of arrows which are generated by dance music, and the patient is required to touch the arrows in appropriate timing. The patients own motion is captured by Kinect, and provided to the patient in real-time as visual feedback. Also, the glove applies vibration feedback as he/she touches the arrows. The patients movements are recorded and analyzed for improved rehabilitation program.

Design of a wearable hand exoskeleton system for evaluation of hand functions

Nowadays, as the number of patients due to stroke increases, interest in rehabilitation treatment has increased and various rehabilitation treatment methods have been developed. In addition, since effective rehabilitation treatment requires quantitative and objective motor function evaluation, several devices were developed and studied. In case of the hand, however, the device which evaluates the hand functions rarely developed because of the space limitation and the complex structure of hand. Therefore, this study aims to design a wearable exoskeleton system capable of evaluating hand functions such as spasticity, finger independence and multi-digit synergy. The designed hand exoskeleton consists of serially connected 4-bar linkages and two rotary actuators for each finger. Thus, MCP and PIP joints can be moved independently, and each joint angle can be measured separately. For DIP joint, the torsion spring was used to move the joint passively. Also, loadcells were attached to each phalanx for measuring external force to the each phalanx. Possible applications are discussed in the conclusion part.

Quantitative evaluation of hand functions using a wearable hand exoskeleton system

To investigate, improve, and observe the effect of rehabilitation therapy, many studies have been conducted on evaluating the motor function quantitatively by developing various types of robotic systems. Even though the robotic systems have been developed, functional evaluation of the hand has been rarely investigated, because it is difficult to install a number of actuators or sensors to the hand due to limited space around the fingers. Therefore, in this study, a hand exoskeleton was developed to satisfy the required specifications for evaluating the hand functions including spasticity of finger flexors, finger independence, and multi-digit synergy and algorithms to evaluate such functions were proposed. The hand exoskeleton was composed with the four 4-bar linkages, two motors, and three loadcells for each finger, and it was able to flex/extend the metacarpal (MCP) and proximal interphalangeal(PIP) joints independently while measuring the pulling force at each phalanx. Using the hand exoskeleton, the hand functions of the three healthy subject were evaluated and the experimental results were analyzed.