• Journal of Institute of Control, Robotics and Systems
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• v.19 no.10
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• pp.936-940
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• 2013

As the ageing population grows around the world, the demand for electric wheelchairs, an important mobility assistance device for the disabled and elderly, is gradually increasing. Therefore, a number of studies related to intelligent wheelchairs are actively underway to improve safety and comfort for wheelchair users. However, previous collision avoidance studies for intelligent wheelchairs have concentrated on collision avoidance methods with the shortest distance and by only changing either velocity or heading angle, rather than considering the forces exerted on the user. If a collision avoidance algorithm that does not consider these forces is applied to an intelligent wheelchair, there is a possibility of an accident due to falling as wheelchair users are generally disabled and elderly people. In this paper, we propose a collision avoidance algorithm which minimizes the forces exerted on a wheelchair user by minimizing the variation of the wheelchair's velocity and heading angle when the sizes, positions, velocities, and heading angles of a wheelchair and a moving obstacle are known.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.133-139
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• 2016

An electric wheelchair is a assistive device to maneuver on the ground. Tip-over of an electric wheelchair is increasing every year. Dynamic stability metric test item in KS P 7176 has not ensured safety of electric wheelchair on the slope. This study presents design the foldable electric wheelchair that can load in the car and analysis of tip-over measurement which is easily computed for electric wheelchair. Wheelchair frame is designed with a four-bar link mechanism for a foldable structure, and seat module, battery and power driving module can be separated. This analysis is performed during a maneuver on the ground by force-moment stability metric. Several elements, center of gravity position, rotational radius and acceleration, were evaluated how to affect stability metric. This stability metric can reduce tip-over of wheelchair and provide a clue to make of dynamic stability test item.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.425-437
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• 2016

Objective:The objective of this study is to develop an ergonomic toilet system along with constituent facilities that can be used with the front-entry sitting method when transferring from wheelchair to the toilet stool, instead of using the back-entry sitting method which is currently used. This system can offer more ease, convenience and safety for wheelchair users when using the restroom. Background: For users with disabilities, even a dedicated handicapped toilet requires maneuvering, especially when in a wheelchair. To transfer from wheelchair to the current back-entry sitting toilet, users need to get closer to the toilet and then turn or twist after erecting their body to get onto the toilet. This method induces inconvenience as well as secondary injury by falling when transferring to/from toilet. Method: To design a front-entry sitting toilet system, an ergonomics approach was applied which introduces a new design concept for people using wheelchairs. Using this toilet system, the wheelchair users don't need to turn or twist but can simply slide forward off the wheelchair directly onto the toilet stool in an easier and safer way. Results: The newly developed front-entry sitting toilet system is easier and safer for wheelchair users, and also space efficient requiring only two-thirds of the space of existing handicapped toilet. It is also usable by both individuals with disabilities and the general population. Conclusion: With the spread of the front-entry sitting toilet system developed in this study, wheelchair users can benefit from enhanced convenience and safety as well as significant restroom space savings. Additional effects can also be achieved such as improved self-esteem of people with disabilities by enabling to use the toilet on their own. Application: The newly developed front-entry sitting toilet system should enhance toilet accessibility to wheelchair users and the elderly. Introduction is needed with efforts at the national policy level and a macroscopic objective to promote the health and safety of the handicapped.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1109-1116
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• 2014

The wheelchair mechanism for a car that is proposed in this study primarily consists of a transfer mechanism and storage mechanism. The wheelchair transfer mechanism consists of a manipulator installed in the roof of a car, and performs the function of transferring the wheelchair from the driver's seat to the trunk. The wheelchair storage mechanism consists of a lifting hoist installed in the trunk of car, and performs the function of storing the transferred wheelchair in the trunk and safely fastening it in place. This study analyzed and reviewed various manipulators, including a vertical type, Scara type, and telescopic type, with the goal of selecting the best type of manipulator for the wheelchair transfer mechanism. The telescopic type was selected and applied because of its good load support and storage capabilities. In addition, with regard to the wheelchair storage mechanism, a slide hoist type that used a slide rail and lift wire and a rotating link hoist type that used a rotating mechanism consisting of a worm gear and link were analyzed and reviewed. The slide hoist type was selected and applied because it had an advantage in relation to trunk space utilization. This study proposed a wheelchair transfer mechanism for a car to support a conventional wheelchair user's movements, and in order to conform to the structure of a domestic welfare car for the disabled.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1509-1512
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• 2003

The electric power wheelchair needs to control motor torque and speed for responding to variable actions given by handling a joystick. In this paper a DSP-based BLDC motor controller using a single dc-link current sensor is presented for electric power wheelchair. It is composed by a DSP processor and three-phase inverter module. To control torque, high speed current control is achieved by the PI controller and pulse width modulation (PWM) signals with 25 kHz carrier frequency, which is performed by 200 ${\mu}sec$ cycle. The speed controller computes the new direct current reference from the speed error and the PI control equation. The displacement value by handling the joystick is converted to reference speeds of right and left wheel motors using nonholonomic wheelchair kinematics. Experimental results show that the presented control system is enough to implement a speed servo in wheelchair driving.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.16-16
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• 2003

In this study, for a safety assessment of wheelchair occupant in side impact, we used a dynamic sled impact test results. The test was carried out total 6 times and impact speed was 13g$\pm$0.43/28km/h$\pm$0.95, By using EURO SID-1 dummy, head performance criteria(HPC), abdominal peak force, etc. were measured. We evaluated wheelchair occupant safety by motion criteria(MC) which was measured by head, trunk and side deformation change of wheelchair and Head & Neck injury criteria(HNI) measured by using head and neck deformation angle and time relation. When we assumed that the maximum injury value in side impact was 100%, the results of motion criteria(MC) of wheelchair occupant were max 80.3, mim 32.3 and average 60.3%, Head & Neck injury criteria(HNI) value were max 118.4, min 14.5 and average 59.7%.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.365-369
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• 2006

According to the IIHS (Insurance Institute fur Highway Safety), side impacts are made up 30% of all accidents (reported 1998). In the case of auto accidents, head and neck injuries were most common as 58%, injuries to the body's trunk equaled 32%, and injuries to the abdomen were 21%. Therefore in this study, injury of wheelchair occupant in frontal and side impact of wheelchair loaded vehicle was analyzed using computer simulation method. The occupant was restrained at the rear of wheelchair by the lap belt. The detailed fixation and restrain conditions of the wheelchair occupant are referred to SAR J2249's recommendation. We estimated HIC(Head Injury Criteria) and HNIC (Head and Neck Injury Criteria) based on measured data.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.120.1-120
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• 2001

This paper proposes a prototype of a safe and reliable wheelchair robot with Human Robot Interaction (HRI). Since the wheelchair users are usually the handicapped, the wheelchair robot must guarantee the safety and reliability for the motion while considering users intention, A single color CCD camera is mounted for input user´s command based on human-friendly gestures, and a ultra sonic sensor array is used for sensing external motion environment. We use face and hand directional gestures as the user´s command. By combining the user´s command with the sensed environment configuration, the planner of the wheelchair robot selects an optimal motion. We implement a prototype wheelchair robot, MR, HURI (Mobile Robot with Human Robot Interaction) ...

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.211-218
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• 2011

We reported the design, prototype, test drive, and mechanical & electrical engineering analyses of a power-lifting wheelchair using mecanum wheels. Mecanum wheels enable translational and rotational movement of the device in any direction on the ground. The power-lifting capability enables the seated individual to reach the standing height of a non-disabled individual. This mecanum wheelchair is fully controlled by the joystick attached to the armrest. The motion of the wheelchair and lifting action of the seat were studied using statics and dynamics. We believe this mecanum wheelchair is a prime candidate for commercial production.

• Proceedings of the KOSOMBE Conference
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• v.1990 no.05
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• pp.63-65
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• 1990

The main concepts in the design and construction of an motorized wheelchair for loading in the car which is intended to drive a disabled to long distance. The wheelchair is basically a powered and folding, so it is designed to motorized manual wheelchair by modularity method. The wheelchair has been installed with a power motor module, battery module, and drive & control module. The goal of this project is to develop a wheelchair that has multifunction and operated disabled who has variety impairment. So we are currently working.