• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.27-37
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• 1995

A performance index is very important and indispensable to the evaluation of automatic steering system of ships in open sea from the viewpoint of energy saving. In this paper, we derive the performance index of automatic steering system from the concept of energy loss of propulsive power. The index is found to consist of three terms, energy loss due to elongation of sailing distance, energy loss due to steering, and energy loss due to yawing motion. We also provide two kinds of calculation method on the performance index ; frequency response analysis and digital simulation. The numerical calculations are carried out for an ore carrier and a fishing boat by both methods. The frequency response analysis is found to be useful if the system is linear and the disturbance on ship is not large. If the system is nonlinear or the disturbance is excessive, the method of digital simulation has to be applied for the accurate evaluation of the performance index. Further investigations into the effects of nonlinear elements such as weather adjuster, power unit etc. on the performance index, will be dealt with in another paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.270-270
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• 2019

Although the Inertial Measurement Unit is applied to a variety of applications such as ships, submarines, and aircrafts, it is mainly used in the attitude measurement area. But since such equipment is expensive, it has been used only in special fields. In this study, the ship's seaworthiness is verified by measuring the speed, direction, gravity, and acceleration of the ship in real time using a low-cost Inertial Measurement Unit. A research method for estimating fIuid force coefficients was devised. Therefore, this study measured ship motion factors at sea, processed and analyzed the measured data, and evaluated the overall safety of the ship and estimated the resistance and steering performance of the ship.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.87-95
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• 2000

The testing product is the HSU(Hydrostatic Steering Unit) installed in the armored vehicle which has the compact structure of assembly with hydraulic pump, hydraulic motor, and several hydraulic valves. There are no assesment testing code for HSU within a country because the testing code for HUS is not involved in the technical concert from USA. Therefore the testing code is developed by the dynamic analysis of the armored vehicle. By the developed testing code, the test equipment is designed, manufactured, and used to apply the assesment test.

• 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.

• International Journal of Automotive Technology
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• v.6 no.6
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• pp.599-604
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension, that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of test and simulation results demonstrates the validity of the proposed functional suspension modeling method. The model is computationally very efficient to achieve real-time simulation on TMS 320C6711 150 MHz DSP board of HILS (hardware-in-the-loop simulation) system for ECU (electronic control unit) evaluation of semi-active suspension.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.397-402
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• 2005

In this paper, to improve the efficiency of welding and user convenience in the shipbuilding industry, a PC-based off-line programming (OLP) technique and the development of a robot transfer unit are presented. The developed OLP system is capable of not only robot motion simulations but also automatic generations of a series of robot programs. The strength of the developed OLP system lies in its flexibility in handling the changes of the welding robot's target objects. Moreover, for a precise transfer of the robot to a desired location, an auxiliary mobile platform named a robot-origin-transfer-unit (ROTU) was developed. To enhance the cornering capability of the platform in a narrow area, the developed ROTU is equipped with 2 steering wheels and 1 driving wheel. Both the OLP and the ROTU were field-tested and their performances were proven successful.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1309-1313
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• 2008

This paper suggests an example of modification of the durability test specifications of electronic control unit for an automotive system in phase of design validation. The basic concept to redefine the specifications of durability test is based on the Arrhenius relationship for accelerated temperature test and the modified Coffin-Manson model for temperature cycle test. The ambient temperature of the powered-event durability test is increased to reduce the required test time of the current specification. Furthermore, the holding time between the events to cool down the temperature of the components is shortened and the resultant temperature rise affects the durability of the components. Thus, the acceleration factor due to the increased temperature range of temperature cycle is also estimated by the modified Coffin-Manson model.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.5-12
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• 2004

A human-friendly interactive system that is based on the harmonious symbiotic coexistence of human and robots is explored. Based on this interactive technology paradigm, a robotic cane is proposed for blind or visually impaired travelers to navigate safely and quickly through obstacles and other hazards faced by blind pedestrians. The proposed robotic cane, "RoJi,” consists of a long handle with a button-operated interface and a sensor head unit that is attached at the distal end of the handle. A series of sensors, mounted on the sensor head unit, detect obstacles and steer the device around them. The user feels the steering command as a very noticeable physical force through the handle and is able to follow the path of the robotic cane easily and without any conscious effort. The issues discussed include methodologies for human-robot interactions, design issues of an interactive robotic cane, and hardware requirements for efficient human-robot interactions.ions.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.32-42
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• 2005

In this paper, to improve the efficiency of welding and user convenience in the shipbuilding industry, a PC-based off-line programming (OLP) technique and the development of a robot transfer unit are presented. The developed OLP system is capable of not only robot motion simulations but also automatic generations of a series of robot programs. The strength of the developed OLP system lies in its flexibility in handling the changes of the welding robot's target objects. Moreover, for a precise transfer of the robot to a desired location, an auxiliary mobile platform named a robot-origin-transfer-unit (ROTU) was developed. To enhance the cornering capability of the platform in a narrow area, the developed ROTU is equipped with 2 steering wheels and 1 driving wheel. Both the OLP and the ROTU were field­tested and their performances were proven successful.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.1
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• pp.29-34
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• 2022

In this paper, we analyze the Non-Holonomic Constraint (NHC) satisfaction of Inertial Navigation System (INS) for vehicular navigation according to Inertial Measurement Unit (IMU) location. In INS-based vehicle navigation, NHC information is widely used to improve INS performance. That is, the error of the INS can be compensated under the condition that the velocity in the body coordinate system of the vehicle occurs only in the forward direction. In this case, the condition that the vehicle's wheels do not slip and the vehicle rotates with the center of the IMU must be satisfied. However, the rotation of the vehicle is rotated by the steering wheel which is controlled based on the Ackermann geometry, where the center of rotation of the vehicle exists outside the vehicle. Due to this, a phenomenon occurs that the NHC is not satisfied depending on the mounting position of the IMU. In this paper, we analyze this problem based on Ackermann geometry and prove the analysis result based on simulation.