• Science of Emotion and Sensibility
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• v.7 no.4
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• pp.19-24
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque. Therefore, the estimation of damping property from the isokinetic movement is difficult.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.417-422
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• 1990

For the robot manipulator in performing precision task, it is indispensable that the robot utilize the various sensors for intelligence. This paper presents the development and implementation of an integrated control system for the control of robotic manipulator, a feeder, a conveyor belt system, force/torque sensor system, and a photo sensor system. Micro controller board was constructed for hierarchical control of the system. To set up the program interactively, a user can make use of the software which includes the full-down menu and a dialog box. The user can make progress the program quickly and easily by a mouse. The related software was written in C and assembly languages.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1043-1046
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• 2002

In this paper, drill tests were carried out by modifying drill geometry for burr minimization. Final objective of this study is to develop compatible drill shape for minimization of burr formation. These experimented results with modified drill are measured with laser sensor after performing drilling with variable material. Simultaneously, the cutting force and the torque of various drill geometry have been observed with same cutting condition to judge drill stability. As a result, burr was minimized in step drill with 75$^{\circ}$ step angle at every material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1879-1882
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• 2005

Due to increase of demands on safety and convenience for automotive vehicle, the use of DC motor, such as power window, seat adjusting, pedal adjusting, sunroof, electric shift motor and so on, is increasing rapidly in the whole world. Worm gear is an important part to transmit torque to another gear in gear mechanism of automotive DC motor. But with current forming process, it has some problems in manufacturing and the quality. Also, the characteristics of automotive parts such as price and mass-production limit the quality improvement. Recently several methods are used in order to reduce a worm screw machining time and to maintain precision. In this paper, we introduce whirling tool machining and side milling cutter machining as effective manufacturing method of worm screw and study on the cutting force of side milling cutter and whirling tool in worm screw machining.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.376-384
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• 2023

In this paper, we introduce an upper extremity rehabilitation robot, NREH (NRC End-effector based Rehabilitation arm at Home). Through NREH, stroke survivors could continuously exercise their upper extremities at home. NREH allows a user to hold the handle of the end-effector of the robot arm. NREH is a end-effector-based robot that moves the arm on a two-dimensional plane, but the tilt angle can be adjusted to mimic a movement similar to that in a three-dimensional space. Depending on the tilting angle, it is possible to perform customized exercises that can adjust the difficulty for each user. The user can sit down facing the robot and perform exercises such as arm reaching. When the user sits 90 degrees sideways, the user can also exercise their arms on a plane parallel to the sagittal plane. NREH was designed to be as simple as possible considering its use at home. By applying error augmentation, the exercise effect can be increased, and assistance force or resistance force can be applied as needed. Using an encoder on two actuators and a force/torque sensor on the end-effector, NREH can continuously collect and analyze the user's movement data.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.454-461
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• 2019

In autonomous interventions using an underwater vehicle with a manipulator, grasping based on target detection and recognition is one of the core technologies. To complete an autonomous grasping task, the vehicle body approaches the target closely and then holds it through operating the end-effector of the manipulator, while the vehicle maintains its position and attitude without unstable motion. For vehicle motion control, it is very important to identify the hydrodynamic parameters of the underwater vehicle, including the propulsion force. This study examined the propulsion characteristics of the autonomous intervention ROV developed by KRISO, because there is a difference between the real exerted force and the expected force. First, the mapping between the input signal and thrusting force for each underwater thruster was obtained through a water tank experiment. Next, the real propulsion forces and moments of the ROV exerted by thrusting forces were directly measured using an F/T (force/torque) sensor attached to the ROV. Finally, the differences between the measured and expected values were confirmed.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.723-730
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• 2007

The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.57-61
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• 2005

This paper presents a new colonoscopy training simulator that includes a specialized haptic device and graphics algorithms to transfer haptic sensation through a long and flexible tube, and manage large number of polygons. The developed haptic device makes the colonoscope tube move along the two guiding rods in the translational direction. The torque of the roll motion is transferred by a timing belt and pulleys. A special guide is developed, which allows the force and torque from the motors to be transmitted to the user without loss. The haptic device is evaluated by physicians. One of the important skills of the colonoscopy, jiggling is incorporated for the first time by the developed sensor mechanism using photo-sensors. A colonoscope handle that shares the look, feel, and functions with the actual colonoscope, is developed with the necessary electronics inside. The number of polygons is reduced by an edge-collapse algorithm for real-time simulation. The algorithms to import CT data, to segment the colon image, to extract centerline of the colon, and to construct the colon surface, are integrated into a Colon Modeling Kit system that performs all these processes in real-time.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.5
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• pp.538-542
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• 2009

Industrial manipulators have been mostly used in large companies such as automakers and electronics companies. In recent years, however, demands for industrial manipulators from small and medium-sized enterprises are on the increase because of shortage of manpower and high wages. Since these companies cannot hire robot engineers for operation and programming of a robot, intuitive teaching and playback techniques of a robot manipulator should replace the robot programming which requires substantial knowledge of a robot. This paper proposes an intuitive teaching and playback algorithm used in assembly tasks. An operator can directly teach the robot by grasping the end-effector and moving it to the desired point in the teaching phase. The 6 axis force/torque sensor attached to the manipulator end-effector is used to sense the human intention in teaching the robot. After this teaching phase, a robot can track the target position or trajectory accurately in the playback phase. When the robot contacts the environment during the teaching and playback phases, impedance control is conducted to make the contact task stable. Peg-in-hole experiments are selected to validate the proposed algorithm since this task can describe the important features of various assembly tasks which require both accurate position and force control. It is shown that the proposed teaching and playback algorithm provides high positioning accuracy and stable contact tasks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.725-728
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• 2008

An elbow orthosis with a pneumatic rubber actuator has been developed to assist and enhance upper limbs movements and has been examined for the effectiveness. The effectiveness of the elbow orthosis was examined by comparing muscular activities during alternate dumbbell curl motion wearing and not wearing the orthosis. The subjects participated in the experiment were younger adults in their twenties. The subjects were instructed to perform dumbbell curl motion in a sitting position wearing and not wearing orthosis in turn and a dynamometer was used to measure elbow joint torque outputs in an isokinetic mode. Orthosis was controlled using contractile muscle force that is measured from force sensor through cDAQ-9172 board. The air pressure of the pneumatic actuator was 0.3MPa the most suitable air pressure. For the analysis of muscular activities, Electromyography of the subjects was measured during alternate dumbbell curl motion. The experiment results showed that the muscular activities wearing the elbow orthosis were reduced. With this, we confirmed the effectiveness of the developed elbow orthosis.