• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.1
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• pp.25-32
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• 2000

A combination steering system was designed to provide the flexibility in controlling the steering wheel in fishing operations of the inshore and coastal fishing vessels. The designed steering system basically is consisted of three driving units, such as a electrically driven hydraulic pump unit with a solenoid control valve, a DC motor driven hydraulic pump unit and a manually driven hydraulic pump unit, and two controllers to provide remote steering on the deck, respectively. The steering torque was measured and analyzed to investigate the dynamic performance of the developed steering system. The steering system showed excellent linearity between the working pressure of cylinder and the torque of rudder post in case of increasing in rudder angle from $5^{\circ} to 35^{\circ}$ that is, the steering torque increased from $10.4 kgf{\cdot}m$ to $105.3 kgf{\cdot}m$ and then the working pressure of cylinder fluctuated from 6.3 kgf/cm super(2) to 16.4 kgf/cm super(2). The steering time of 3.2 sec in remote hydraulic steering by the on/off solenoid valve control was much faster than 13.2 sec in the manual steering by the helmsman and 11.6 sec in the electric steering by a DC motor, and then it was verified that operation of one unit does not affect other units in combination steering system in any way. Furthermore, the developed steering system can be remotely controlled in multiple stations of the deck during the fishing operation and the automatic pilot steering unit can be used to add hydraulic steering.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1995.11a
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• pp.153-165
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• 1995

When an automatic course-keeping is introduced as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit(or telemotor unit) steering gear ship dynamics and magnetic or gyro compass. We derive the mathematical model of each element of the automatic steering system. We provide a method of theoretical analysis on propulsive energy loss related to automatic steering of ships inthe open seas taking account of the on-off mechanism of power unit. Also we paid attention to dead band mechanism of autopilot device which is normally called weather adjustment. Next we make numerical calculation of the effects of autopilot control constants ont he propulsive energy loss for two kinds of ship a fishing boat and an ore carrier. Realistic sea and wind disturbances are employed in the calculation.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.94-100
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• 2004

Most power steering systems obtain the power by a hydraulic mechanism. Therefore, it consumes more energy because the oil power should be sustained all the times. Recently, to solve this problem the electric power system has been developed and become widely equipped in passenger vehicles. In this research the simulation integration technique for an electric power steering system with MATLAB/SIMULINK and a full vehicle model with ADAMS has been developed. A full vehicle model interacted with electronic control unit algorithm is concurrently simulated with an impulsive steering wheel torque input. The dynamic responses of vehicle chassis and steering system are evaluated. This integrated method allows engineers to reduce the prototype testing cost and to shorten the developing period.

• Korean Journal of Agricultural Science
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• v.37 no.1
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• pp.123-130
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• 2010

A steering control system based on CAN(Controller Area Network) for autonomous tractor was developed to reduce duty of a central processing computer and to improve performance of steering control in terms of reduced control interval and error. The steering control system consisted of a SCU (Steering Control Unit), an EHPS system, and a potentiometer. The SCU consisted of an MCU (Micro Controller unit), an A/D converter, and a DC-DC converter, and a PID controller was used to control steering angle. The steering control system was communicated with the computer by CAN-bus. Each actuator and implement was connected to a multi-function board interfacing with the computer through a USB cable. Without CAN, control interval of the autonomous tractor was 1.5 seconds. When the CAN-based steering control system was combined with the autonomous tractor, however, control interval of the integrated system was reduced to those less than 0.05 seconds. When the autonomous tractor was operated with 1.5-s and 0.05-s control cycles at a 0.63-m/s travelling speed, the trajectories were close to straight lines for both of the control cycles. For a 1.34-m/s traveling speed, tractor trajectory was close to sine wave with a 1.5-s control cycle, but was straight line with a 0.05-s control cycle.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.698-703
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• 1990

This paper describes an Electronically-controlled Power Steering system which is developed by the modification of a conventional power steering based on so called rotary valve technology. The steering effort is influenced by the electrohydraulic flow rate control of the pressurized oil to rotary valve. The vehicle speed and the steering angular velocity are used to calculate and output a signal to proportional flow rate control valve by the Electronic Control Unit. The improvement of the steering feel was satisfactory compared with that of the original conventional power steering.

• Journal of the Korean Institute of Navigation
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• v.22 no.1
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• pp.79-89
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• 1998

When an automatic course-keeping is concerned , as is quite popular in modern navigation, the closed-loop steering system consists of autopilot device, power unit(or telemotor unit), steering gear, magnetic or gyro compass and ship dynamics. In order to estimate steering system of ship in open seas, we need to know the characteristics of each component of the system and also to know the characteristics of disturbance to ship dynamics. Calculation methods of irrgular disturbances are based on the linear superposition principle. In this paper, for the purpose of evaluation of automatic steering of ships , the influences of linear control constants of autopilot on propulsive energy loss are investigated bya performance index is introduced from the viewpoint of energy saving. Numberical calculations are carried out for an are carrier and for a fishing boat in multi-directional waves.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1366-1370
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• 2005

As the development of microprocessor technology, electric power steering (EPS) system which uses an electric motor came to use a few years ago. It can solve the problems associated with hydraulic power steering. The motor only operates when steering assistance is needed, so it can save fuel and can reduce weight and cost by eliminating hydraulic pump and piping. As one of performance criteria of EPS systems, the transmissibility from road wheel load to steering wheel torque is considered in the paper. The transmissibility can be studied by fixing the steering wheel and calculating the torque needed to hold the steering wheel from road wheel load. A proportion-plus-derivative control is needed for EPS systems to generate desired static torque boost and avoid transmissibility of fluctuation. A pure proportion control can't satisfy both requirements.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.92-98
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• 2008

A beam steering system of X-band 2-D phased array antenna for radar application is developed. The beam steering system consists of real-time command generator, beam steering unit, control PCB of array module and power supply. It plays a role of beam steering and on-line check of phased array antenna. The performance of beam steering system is verified with pulse timing of current control in phase shifters and measurement of far-field of phased array antenna. The developed beam steering system offers basic technology to develop full-scale beam steering system of multi-function radar.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.04a
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• pp.77-92
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• 1996

When an automatic course-keeping is concerned as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit (or telemotor unit) steering gear magnetic or gyro compass and ship dynamics. The consideration of irregular disturbances to ship dyanmics and a few non-linear mechanisms involved in the system inevitably or artificially are known to be very important in properly evaluating or analyzing the automatic steering system. In the present study the mathematical model of each element of an automatic steering system is derived which takes account of a fex non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. The calculation method of imposing irregular disturbances to ship dynamics is proposed where irregular disturbances implying irregular wave and the fluctuating component of wind. For he evaluation of automatic steering system of ships in the open seas an important term "performance index" is introduced from the viewpoint of energy saving which derived from the concept of energy loss on ship propulsion. Finally the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of linear and/or non-linear control constants of autopilot on propulsive energy loss are investigated to validate and clarify the present smulation technique.

• Journal of the Korean Institute of Navigation
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• v.19 no.3
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• pp.11-19
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• 1995

When an automatic course keeping is introduced, as is quite popular in modern navigation, the closed-loop control system consists of autopilot device, power unit, steering gear, ship dynamics, and magnetic or gyrocompass. We derive mathematical models of each element of the automatic steering system. We provide a method of theoretical analysis on the propulsive energy loss related to automatic steering of ships in the open seas, taking account of the on-off(non-linear) characteristics of power unit. Also we paid attention to non-linear element installed in autopilot device, which is normally called weather adjuster. Next we make numerical calculation of the effects of autopilot control constants on the propulsive energy loss for two kinds of ship, a fishing boat and an ore carrier. Realistic sea and wind disturbances are employed in the calculation.