• 로봇학회논문지
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• 제14권4호
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• pp.318-325
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• 2019

NREX, an upper limb exoskeleton robot, was developed at the National Rehabilitation Center to assist in the upper limb movements of subjects with weak muscular strength and control ability of the upper limbs, such as those with hemiplegia. For the free movement of the shoulder of the existing NREX, three passive joints were added, which improved its wearability. For the flexion/extension movement and internal/external rotation movement of the shoulder of the robot, the ball lock pin is used to fix or rotate the passive joint. The force and torque between a human and a robot were measured and analyzed in a reaching movement for four targets using a six-axis force/torque sensor for 20 able-bodied subjects. The addition of two passive joints to allow the user to rotate the shoulder can confirm that the average force of the upper limb must be 31.6% less and the torque must be 48.9% less to perform the movement related to the axis of rotation.

• 한국정밀공학회지
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• 제26권7호
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• pp.134-141
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• 2009

Recently, many researchers have tried to develop wearable robots for various fields such as medical and military purposes. We have been studying robotic exoskeletons to assist the motion of persons who have problems with their muscle function in daily activities and rehabilitation. The upper-limb motions (shoulder, elbow and wrist motion) are especially important for such persons to perform daily activities. Generally for shoulder motion 300F is needed to describe its motion(extension/flexion, abduction/adduction, internal/external rotation) but we have used a redundant actuator thus making a 4 DOF system. In this paper, we proposed the mechanism design of the exoskeleton which consists of 4-DOF for shoulder and 1-DOF for elbow robotic exoskeleton to assist upper-limb motion. Then we compared the new mechanism design and prototype mechanism design. Here we also analyze the proposed system kinematically to find out and to avoid the singular point. This research will ensure that the proposed wearable robot system make human's motion more powerfully and more easily.

• 제어로봇시스템학회논문지
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• 제21권5호
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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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.46-51
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• 2004

This paper presents an adaptive control method based on parameter linearization for incompletely restrained wire-suspended mechanisms. The main purpose of this control method is utilizing it in a walking assist service robot for elderly people. This method is computationally simple and requires neither end-effector acceleration feedback nor inversion of estimated inertia matrix. In the proposed adaptive control law, mass, moment of inertia and external force and torque on the end-effector are considered as components of parameter adaptation vector. Nonlinear simulation for walking an elderly shows the effectiveness of the parameter adaptation law.

• 대한인간공학회지
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• 제33권5호
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• pp.407-422
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• 2014

Objective: The purpose of the study is to develop quantitative usability evaluation criteria for senior-friendly autonomous transportation robot. Background: The Republic of Korea has become the most rapidly aging society, and is anticipated to enter the post-aged society in 2026. To raise the quality of life of a senior with limited mobility and to reduce the burden of caregivers, many high-tech assistive products with information technologies are developed nowadays. The senior-friendly autonomous transportation robot is one person robot vehicle to move a senior to the destination for hospitals, nursing homes or silver town complex. With built-in navigation system and environmental monitoring censors, it automatically seeks the path to the destination and avoids collision to obstacles and pedestrians on the way. Due to the early stage of the product, few usability studies in this field have been done, mostly on general service robots to assist seniors, power wheelchairs and delivery robots. ISO and KS standards for the service robots are focused on safety. Method: Based on the reference usability index, the early draft of the usability evaluation questionnaires was developed. After small group tests and interviews, the experts modified the initial draft to the Usability Evaluation Criteria for Senior-Friendly Autonomous Transportation Robot (UEC-SFATR). Result: UEC-SFATR consisted of 4 subscales - Safety, Controllability, Efficiency and Satisfaction. All of the 4 subscales of UEC-SFATR were passed the reliability criteria by 4 groups of seniors, divided by gender and familiarity of smart-devices. Conclusion: UEC-SFATR covers wider area of user experiences of the SFATR and is a good measurement tool to help both the users and developers of the robot. Application: This study provides guide to the future product development and product competitiveness evaluation by quantifying user experiences for the SFATR.

• Transactions on Control, Automation and Systems Engineering
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• 제4권1호
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• pp.49-55
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• 2002

A decrease in the birthrate and aging are progressing in Japan and several countries. In that society, it is important that physically weak persons such as elderly persons are able to take care of themselves. We have been developing exoskeletal robots for human (especially for physically weak persons) motion support. In this study, the controller controls the angular position and impedance of the exoskeltal robot system using multiple fuzzy-neuro controllers based on biological signals that reflect the human subject's intention. Skin surface electromyogram (EMG) signals and the generated wrist force by the human subject during the elbow motion have been used as input information of the controller. Since the activation level of working muscles tends to vary in accordance with the flexion angle of elbow, multiple fuzzy-neuro controllers are applied in the proposed method. The multiple fuzzy-neuro controllers are moderately switched in accordance with the elbow flexion angle. Because of the adaptation ability of the fuzzy-neuro controllers, the exoskeletal robot is flexible enough to deal with biological signal such as EMG. The experimental results show the effectiveness of the proposed controller.

• 한국군사과학기술학회지
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• 제17권6호
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• pp.853-860
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• 2014

This paper introduces a Korean rescue robot and presents a whole body kinematic control strategy. The mission of the rescue robot is to move and lift patients or soldiers with impaired mobility in the battlefields, hospitals and hazardous environments. In order for a robot to rescue and assist humans, reliable mobility in various environments, large load carrying capacity, and dextrous manipulability are required. For these objects the robot has variable configuration mobile platform with tracks, dual arm manipulator, and two types of grippers. The electric actuators provide the strength to lift a wounded soldier up to 120 kg using whole body joints. To control the robot with multi degree of freedom, we need to synthesize complex whole-body behaviors, and to manage multiple task primitives systematically. We are to present a whole body kinematic control methodology, and demonstrate its effectiveness through numerical simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권5호
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• pp.1339-1355
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• 2023

Localization is a hot research spot for many areas, especially in the mobile robot field. Due to the weak signal of the global positioning system (GPS), the alternative schemes in an indoor environment include wireless signal transmitting and receiving solutions, laser rangefinder to build a map followed by a re-localization stage and visual positioning methods, etc. Among all wireless signal positioning techniques, Wi-Fi is the most common one. Wi-Fi access points are installed in most indoor areas of human activities, and smart devices equipped with Wi-Fi modules can be seen everywhere. However, the localization of a mobile robot using a Wi-Fi scheme usually lacks orientation information. Besides, the distance error is large because of indoor signal interference. Another research direction that mainly refers to laser sensors is to actively detect the environment and achieve positioning. An occupancy grid map is built by using the simultaneous localization and mapping (SLAM) method when the mobile robot enters the indoor environment for the first time. When the robot enters the environment again, it can localize itself according to the known map. Nevertheless, this scheme only works effectively based on the prerequisite that those areas have salient geometrical features. If the areas have similar scanning structures, such as a long corridor or similar rooms, the traditional methods always fail. To address the weakness of the above two methods, this work proposes a coarse-to-fine paradigm and an improved localization algorithm that utilizes Wi-Fi to assist the robot localization in a geometrically similar environment. Firstly, a grid map is built by using laser SLAM. Secondly, a fingerprint database is built in the offline phase. Then, the RSSI values are achieved in the localization stage to get a coarse localization. Finally, an improved particle filter method based on the Wi-Fi signal values is proposed to realize a fine localization. Experimental results show that our approach is effective and robust for both global localization and the kidnapped robot problem. The localization success rate reaches 97.33%, while the traditional method always fails.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.309-315
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• 2015

This paper presents a lower-limb exoskeleton testbed and its control method. An exoskeleton is a wearable robotic system that can enhance wearer's muscle power or assist human's movements. Among a variety of its applications, especially for military purpose, a wearable robot can be very useful for carrying heavy loads during locomotion by augmenting soldiers' mobility and endurance. The locomotion test on a treadmill was performed up to maximum 4km/h walking speed wearing the lower-limb exoskeleton testbed with a 45kg backpack load.

• 대한기관식도과학회지
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• 제17권2호
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• pp.89-91
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• 2011

Robotic surgery have been increasingly applied in the past several years to assist in a variety of operations. Some applications, such as in prostatectomy, have been widely adopted and have largely supplanted the alternative minimally invasive or open techniques. However, the use of surgical robots in esophagectomy has not been as common. Although a limited number of case reports demonstrated the feasibility of robotic esophagectomy, no large series of patients has been reported to date. The data on robotic-assisted esophagectomy suggest that the procedure is safe, feasible, and associated with perioperative outcomes similar to open and minimally invasive esophagectomy. Benefits of robotic system could be maximized when we do a extensive total mediastinal lymphadenectomy. For this procedure to gain widespread acceptance, identifiable benefit relative should be demonstrated in near future.