• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.2
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• pp.147-156
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• 1996

In this paper we proposed a beam steering equation for the planar slotted waveguide array antenna. The tilt angle measured from the rotating axis and the aperture distribution of the antenna were the most important factors for the beam steering. From the equation, we calculated the frequency and phase distribution of the aperture for any desired beam direction. And we developed a high speed control algorithm delivering the phase data to the phase shifters of a one-dimensional phased array antenna. To reduce complexity of the control circuit and the phase delivery time, we proposed the serial phase repeating method. Because of its simplicity, we expect it can be useful for a large 2- dimensional fully phased array antenna.

• Journal of Welding and Joining
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• v.26 no.6
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• pp.59-66
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• 2008

Recently, automobile parts progress with modularization, which a great many allied products are modularized. Therefore, the purpose of this study is to develope modular housing for modularization of steering gear. Generally, steering gear housing is composed of valve housing and rack housing, it is important to combine two housings. However, housing having the pipe shape is very sensitive to welding distortion, and welding trajectory is very complicated. In order to solve this subject, cooperative control by using robots was constructed. Further, we developed the dedicated system to suit modular housing based on it, and applied laser welding to there. Moreover, welding speed was controlled in the rapid curve section so that the defect in trajectory of housing was reduced to obtain sound weldment. Accordingly, produced housing by this way is presented enough withstanding pressure to $100kg/cm^2$, and roundness and straightness are measured about 10/100 and 0.9/100 respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.196-196
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• 2000

This paper describes a lateral guidance system of an autonomous vehicle, using a neural network model of magneto-resistive sensor and magnetic fields. The model equation was compared with experimental sensing data. We found that the experimental result has a negligible difference from the modeling equation result. We verified that the modeling equation can be used in simulations. As the neural network controller acquires magnetic field values(B$\_$x/, B$\_$y/, B$\_$z/) from the three-axis, the controller outputs a steering angle. The controller uses the back-propagation algorithms of neural network. The learning pattern acquisition was obtained using computer simulation, which is more exact than human driving. The simulation program was developed in order to verify the acquisition of the teaming pattern, teaming itself, and the adequacy of the design controller. The performance of the controller can be verified through simulation. The real autonomous electric vehicle using neural network controller verified good results.

• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.323-333
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• 2011

Due to the limited pendulum motion range, the conventional one-pendulum driven spherical robot has limited driving capability. Especially it can not drive parallel direction with center horizontal axis to which pendulum is attached from stationary state. To overcome the limited driving capability of one-pendulum driven spherical robot, we introduce a spherical robot, called KisBot II, with a new type of curved two-pendulum driving mechanism. A cross-shape frame of the robot is located horizontally in the center of the robot. The main axis of the frame is connected to the outer shell, and each curved pendulum is connected to the end of the other axis of the frame respectively. The main axis and pendulums can rotate 360 degrees inside the sphere orthogonally without interfering with each other, also the two pendulums can rotate identically or independent of each other. Due to this driving mechanism, KisBot II has various motion generation abilities, including a fast steering, turning capability in place and during travelling, and four directions including forward, backward, left, and right from stationary status. Experiments for several motions verify the driving efficiency of the proposed spherical robot.

• International journal of advanced smart convergence
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• v.11 no.1
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• pp.94-100
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• 2022

It is common for commercial vehicles to make the top part according to the use after making the bear chassis, and to connect various devices with the bear chassis. Various brackets used in bear chassis for the development of all automobiles, including commercial vehicles, play a role of connecting the components required for driving and operating the car to the car body. In commercial vehicles, components necessary for operation are installed in the bear chassis; that is, the bear chassis of commercial vehicles is a space where the devices required for driving and operating the vehicle are installed. The devices required for the configuration of the vehicle are drive, brake, exhaust and steering, etc. These devices are basically connected to the body, the front axis, or the rear axis. The part interlinking the apparatuses required for the vehicle drive to the car body or axis is bracket. In this study, we analyzed the boundary conditions to evaluate the stability of the three brackets that connect the components of the car to the front axis of the new type of 30-seater bus in the development process. In order to analyze the boundary conditions, the boundary conditions according to the driving condition of the vehicle were classified. For stress analysis to evaluate the stability of brackets according to the driving state of the vehicle, it is reasonable to give the bracket a boundary condition of harsh conditions.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.181-186
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• 2005

In this paper, an estimation system of vehicle position and orientation on magnetic lane, which is a parameter of the steering controller for automated lane follwing is described. To verify that the magnetic dipole model could be applied to a magnetic unit paved in roadway, the analysis of the the data 3-axis magnetic field measured experimentally.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.89-98
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• 2009

CMG cluster which consists of four CMGs can be used to produce 3-axis torque. There are many issues that we have to investigate and validate when CMG cluster itself is developed. Thus, its ground validation and verification processes are essential. Therefore, CMG simulator which uses a torque sensor to calculate satellite attitude is proposed in this paper. Update and kalman filter are also proposed for gimbal angle problem occurred in development. The first way uses a calculated gimbal angle as a primary and a sensor angle as a scondary to reduce error. Also, the test results of specific CMG steering law as well as attitude control logic are presented as an example.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1418-1425
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• 2014

In ultrasonic medical imaging, spatial compounding of images is a technique where ultrasonic beam is steered to examine patient tissues in multiple angles. In the conventional ultrasonic diagnostic imaging, the steering of the ultrasonic beam is achieved electronically using the phased array transducer elements. In this paper, a spatial compounding approach is presented where the ultrasonic probe element is rotated mechanically and the beam steering is achieved mechanically. In the spatial compounding, target position is computed using the value of the rotation axis and the transducer array angular position. However, in the process of the rotation mechanism construction and the control system there arises the inevitable uncertainties in these values. These geometric parameter errors result in the target position error, and the consequence is a blurry compounded image. In order to reduce these target position errors, we present a spatial compounding scheme where error correcting transformation matrices are computed and applied to the raw images before spatial compounding to reduce the blurriness in the compounded image. The proposed scheme is illustrated using phantom and live scan images of human knee, and it is shown that the blurriness is effectively reduced.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.85-92
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• 2024

In this paper, we developed an intuitive teaching and control system that directly teaches a task by holding the tip of a robotic arm and moving it to a desired position. The developed system consists of a 6-axis force sensor that measures position and attitude forces at the tip of the robot arm, an algorithm for generating robot arm joint speed control commands based on the measured forces at the tip, and a self-made 6-axis robot arm and control system. The six-dimensional force/torque of the position posture of the robot arm operator steering the handler is detected by the force sensor attached to the handler at the leading edge and converted into velocity commands at the leading edge to control the 7-axis robot arm. The verification of the research method was carried out with a self-made 7-axis robot, and it was confirmed that the proposed force sensor-based robot end-of-arm control method operates successfully through experiments by teaching the operator to adjust the handler.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.6
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• pp.531-537
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• 2008

One of the fundamental features of time reversal acoustic (TRA) techniques is the ability to focus the propagating ultrasonic beam to a specific point within the test material. Therefore, it is important to understand the focusing properties of a TR device in many applications including nondestructive testing. In this paper, we employ an analytical scheme for the analysis of TR beam focusing in a homogeneous medium. More specifically, a nonparaxial multi-Gaussian beam (NMGB) model is used to simulate the focusing behavior of array transducers composed of multiple rectangular elements. The NMGB model is found to generate accurate beam fields beyond the nonparaxial region. Two different simulation cases are considered here for the focal points specified on and off from the central axis of the array transducer. The simulation results show that the focal spot size increases with increasing focal length and focal angle. Furthermore, the maximum velocity amplitude does not always coincide with the specified focal point. Simulation results for the off-axis focusing cases do demonstrate the accurate steering capability of the TR focusing.