• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.7-12
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• 2013

In this paper, we propose a brushless DC motor drive system for active knee prosthesis and low-cost estimation method for phase current from DC-link current. To control motor torque directly, current sensing is very important and current sensing point should be synchronized with voltage switching command to minimize the effect of switching noise in current measurement, For maintaining small form factor, simplifying control schemes and achieving low-cost system, control schemes using DC-link current are used. Moreover, we incorporated phase current estimation method using analog MUX for minimizing current estimation error between DC-link current and phase current. The validity of the proposed system is verified through experimental works.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3_1spc
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• pp.587-592
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• 2013

Until recently, the primary users of wheelchairs were people with lower body disabilities. However, the number of patients recovering from accidents or surgery, as well as the number of elderly people using wheelchairs, is constantly increasing. This study examined the design and manufacture of standing and gait assist wheelchairs that assist temporary gait disturbed patients to take rehabilitation training and elderly people to engage in walking exercise. A kinematic analysis was used to select a drive motor and design a four-bar linkage mechanism for lifting the backrest vertically. Using a multibody dynamic simulation, detailed design was performed taking into consideration the spatial motion and partial interference, and the necessary push force and stroke of the linear actuator were also calculated. To ensure structural safety, the von-Mises equivalent stresses of the upper and lower brackets of the linear actuator were verified through a finite element analysis. The manufactured wheelchair was shown to operate successfully as intended, using the developed controller for the drive motors and linear actuator.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.799-807
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• 2014

This paper describes the development of an indoor locomotion assistive robot, Ball-Chair, comprising a novel drive system. This robot facilitates locomotion assistive operation in narrow spaces, in which common wheelchairs cannot move easily. The Ball-Chair has two main features: its structural feature and driving mechanism. The exoskeleton frames of the Ball-Chair have been designed with octagonal shapes resembling a circle, for minimizing its volume and weight. Additionally, all its driving parts (including the ball) are mounted within of the robot to enhance its safety. The Ball-Chair features a reverse ball-mouse driving mechanism comprising two driving omni-wheels in the x- and y-axes. By controlling the speed of each omni-wheel, a holonomic driving system that can facilitate omnidirectional locomotion has been achieved using only two wheels. The effective movement of the Ball-Chair in any direction within narrow indoor spaces was experimentally verified. The paper outlines the development procedure in detail.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.1-6
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• 2009

In this paper, when wheelchair user get into the vehicle, we have thorough grasp of the problems of loading wheelchair and give effect to suggest conceptual design in relation to develop manufactured goods. We choose 50 participants with disabilities who manual wheelchair or motor scooter users are able to drive own's vehicle, and the method practice in the direct survey. There are some limitations in this study especially in terms of the sampling population. The 88%(n=44) of the participant replied to the driver with disabilities need assistive devices for loading manual wheelchair. They prefer a system that robot arm brings the wheelchair out of the trunk to the driver's seat door.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.111-116
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• 2019

With the recent acceleration of industrial technologies and active research, wearable robot technologies have been applied to various fields. To study the utility of wearable robots, basic research on kinetic mechanisms of the human body, bio-signal analysis, and system control are essential. In this study, we investigated the basic structure of a wearable system and the operating principles of a driving mechanism. The control system and supporting structure, which comprise the driving mechanism, were designed and manufactured. Motion and load analyses were performed simultaneously for the design of the kinematic drive, and the driving mechanism was constructed by analyzing walking motion. The operating conditions of the cylinder were verified by stride via driving experiments. Further, the accuracy and responsiveness of the system were confirmed by comparison with actual motion, and the system safety was validated by applying loads.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.503-509
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• 2015

In this paper, we designed and tested an ankle joint mechanism for a gait rehabilitation robot. Gait rehabilitation programs are designed to improve the natural leg motion of patients who have lost their walking capabilities by accident or disease. Strengthening the muscles of the lower-limbs and stimulation of the nervous system corresponding to walking helps patients to walk again using gait assistive devices. It is an obvious requirement that the rehabilitation system's motion should be similar to and as natural as the normal gait. However, the system being used for gait rehabilitation does not pay much attention to ankle joints, which play an important role in correct walking as the motion of the ankle should reflect the movement of the center of gravity (COG) of the body. Consequently, we have designed an ankle mechanism that ensures the safety of the patient as well as efficient gait training. Also, even patients with low leg muscle strength are able to operate the ankle joint due to the direct-drive mechanism without a reducer. This safety feature prevents any possible adverse load on the human ankle. The additional degree of freedom for the roll motion achieves a gait pattern which is similar to the normal gait and with a greater degree of comfort.

• Journal of the Korea Society of Computer and Information
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• v.15 no.10
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• pp.35-47
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• 2010

To complement inaccurate edge information and detect correctly the boundary of a vehicle in an image, an extended edge analysis technique is presented in this paper. The vehicle is detected using the bottom boundary generated by a vehicle and the road surface and the left and right side boundaries of the vehicle. The proposed extended edge analysis method extracts the horizontal edge by merging or dividing the nearby edges inside the region of interest set beforehand because various noises deteriorates the horizontal edge which can be a bottom boundary. The horizontal edge is considered as the bottom boundary and the vertical edges as the side boundaries of a vehicle if the extracted horizontal edge intersects with two vertical edges which satisfy the vehicle width condition at the height of the horizontal edge. This proposed algorithm is more efficient than the other existing methods when the road surface is complex. It is proved by the experiments executed on the roads having various backgrounds.