• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.260-265
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• 2022

In this study, we establish hyper-elastic haptic feedback in a virtual environment using finite element analysis techniques and develop a Force Torque (FT) sensor utilization method for application in tele-operation environments. In general, regarding haptic feedback data, in a tele-operation environment, the user is provided with feedback according to the measured force data when the model is inserted through an FT sensor. Conversely, in a virtual environment, the press-fitting model can be expressed through the spring-damper system rather than an FT sensor to provide feedback. However, unlike rigid and the elastic bodies, the hyper-elastic body represented by a spring-damper system in a virtual environment is a simple impedance model using stiffness and damping coefficients; it is limited in terms of providing actual feedback. Thus, in this study, haptic feedback was implemented using the data obtained from POD-RBF analysis results during hyper-elastic press-fitting experiments. The haptic feedback mechanism developed in this study was verified by comparing the FT sensor feedback data measured and calculated through hyper-elastic press-fitting experiments with spring-damper feedback data. Subsequently, the POD-RBF analysis feedback was compared and evaluated against the feedback mechanism of each environment through the test subject, and the similarities between the POD-RBF analysis feedback and FT sensor data feedback were verified.

• The Journal of Korea Robotics Society
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• v.1 no.2
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• pp.135-141
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• 2006

This paper presents offline estimation of equivalent physical damping parameter in haptic interaction systems where damping is the most important parameter for stability. Based on the previous energy bounding algorithm, an offline procedure is developed in order to estimate the physical damping parameter of a haptic device by measuring energy flow-in to the haptic device. The proposed method does not use force/torque sensor at the handgrip. Numerical simulation and experiments verified effectiveness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.8
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• pp.807-814
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• 2014

In this paper, we proposed a haptic navigation system which used the tactile data for the user guides of the mobile robot to the reference point via tele-operation in unknown blind environment. This navigation system can enable a mobile robot to avoid obstacles and move to the reference point, according to the direction provided by the device guides through a haptic device consisting of a vibration motor in a blind environment. There are a great deal of obstacles in real environments, and so mobile robots can avoid obstacles by recognizing the exact position of each obstacle through the superposition of an ultrasonic sensor. The navigation system determines the direction of obstacle avoidance through an avoidance algorithm that uses virtual impedance, and lets users know the position of obstacles and the direction of the avoidance through the haptic device consisting of 5 vibration motors. By letting users know intuitionally, it lets the mobile robot precisely reach the reference point in unknown blind environment. This haptic device can implement a haptic navigation system through the tactile sensor data.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.553-559
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• 2015

The purpose of this research is to develop a gait assistive device to enhance the gait stability and training efficiency of stroke patients. The configuration of this device is mainly composed of a motored wheel and a single cane whose lower end is attached to a motored wheel frame. A patient can feel haptic information from continuous ground contact from the wheel while walking through the grip handle. In addition, the wheeled cane can avoid using excessive use of the patient's upper limb for weight support and motivate the patient to use a paralyzed lower limb more actively. Moreover, the proposed device can provide intuitive and safe user interaction by integrating a force sensor and a tilt sensor equipped to the cane frame, and a switch sensor at the cane's handle. The admittance control has been implemented for the patient to change the walking speed intuitively by using the interaction forces at the handle. A hemi-paretic stroke patient participated in the walking assistive experiments as a pilot study to verify the effectiveness of the proposed haptic cane system. The results showed that the patient could improve walking speed and muscle activations during walking with a constant speed mode of the haptic cane. Moreover, the patient could maintain the preferred walking speeds and gait stability regardless of the magnitude of resistance forces with the admittance control mode of the haptic cane. The proposed robotic gait assistive device with a simple and intuitive mechanism can provide efficient gait training modes to stroke patients with high possibilities of widespread utilizations.

• The Journal of Korean Institute for Practical Engineering Education
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• v.5 no.1
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• pp.34-39
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• 2013

This paper suggests an input device that allows a user not only to naturally interact with education contents in virtual environment but also to sense haptic feedback according to his/her interaction. The proposed system measures a user's motion and then creates haptic feedback based on the measured position. To create haptic information in response to a user's interaction with educational contents in virtual environment, we develop a motion input device which consists of a motion controller, a haptic actuator, a wireless communication module, and a motion sensor. To measure a user's motion input, an accelerometer is used as the motion sensor. The experiment shows that the proposed system creates continuous haptic sensation without any jerky motion or vibration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1344-1351
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• 2004

This study develops a haptic display model which is an indispensable for the force generation in the virtual environment. In developing the haptic display model, a Proxy concept and a Karnopp friction model are utilized to generate the reaction force and the friction force. Also this study develops a 2 D.O.F. remote wiping system. This system is composed of a 2 D.O.F. master manipulator, a force sensor equipped 2 D.O.F. slave manipulator and a real time controller. With the developed remote wiping system, this study identifies the friction characteristic of the aluminum, acryl and rubber plate. The results are used as the dynamic friction coefficient of the haptic display model. This study shows the efficiency of the developed haptic display model by the comparison between the friction characteristic of the haptic display with the developed haptic display model and the friction characteristic of the real aluminum, acryl and rubber plate.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1036-1043
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• 2014

In this paper, a new haptic device is proposed for the teleoperation, which can recognize the invisible environment of a mobile robot. With this new device, it is possible for the user to identify the location of an obstacle and to avoid it. The haptic device has been attached on the top of a joystick so that the user can remotely control the mobile robot to avoid the obstacles which are recognized by the ultrasonic sensors. Also, the invisible environment is recognized more accurately overlapping the data from the ultrasonic sensors. There are five vibration motors in the haptic device to indicate the direction of the obstacle. So the direction of the obstacle can be recognized by the vibration at the finger on each vibration motor. For various situations and surrounding environments, experiments are performed using fuzzy controller and overlapping ultrasonic sensors. The results demonstrate the effectiveness of the proposed haptic joystick.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.1030-1035
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• 2011

The remote control of mobile robot is widely used to perform dangerous and complex tasks such as underwater exploration and cleaning of nuclear reactor. For this purpose, the obstacle avoidance process will proceed to ensure a safe drive. In this paper, we tested that mobile robot drive in which replaced a pipe with a box. After we measured the distance around the obstacle through a sensor of robot, we got the information that changed haptic force from the distance of the obstacle.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1285-1288
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• 1997

The basic technology of virtual reality can be described as the cognition of the condition change in virtual world by stimulating the visual, auditory, kinesthetic and tactile sensation. Among these, the kinesthetic and tactile sensation is one of the most important things to recognize the interaction. In this paper, it is addressed the haptic device which help the human feel the sense of the operator, and is designed in modular type to expand for five fingers later. the haptic device is driven by tendon and ultrasonic motors located in the wrist part. Each joint is actuated by coupled tendons and adopts more actrator by one than the number of the joints, called 'N+1 type'. The haptic device adopts metamorphic 4-bar linkage structure and the length of linkages, shape and the location of joint displacement sensor are optimized through the analysis.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2535-2539
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• 2003

The haptic system becomes an essential device in the area of tele-operation, video entertainment and medical operation. To control a haptic device, impedance control method is widely used, but force sensor costs so much that open-loop control method is usually preferred for commercial purpose. In this case, modeled/un-modeled dynamics affects the performance of device. In this paper, we present a new 3DOF five-link type haptic device that we can reduce the effect of device dynamics and compensate its dynamics. We also evaluate its performance.