• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.50-56
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• 2015

Korea district heating systems have mainly used setting temperature control and outdoor reset control. Different from such conventional normal methods, a thermal-load control proposed in Sweden can decrease the return temperature and reduce pump power consumptions because the control is able to provide the appropriate amount of required heat. In this study, further improved predictive optimal control in addition to the conventional controls were simulated in order to verify its effect in district heating system using TRNSYS 17. $200m^2$ apartment housing which accounts for 25% in Korea and is used as a calculation model;. the number of households in the simulation was 9. As a result, a higher temperature difference and decreasing flow rate at primary loop were shown when using thermal-load control.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.11
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• pp.1291-1297
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• 2014

This paper proposes integrated chassis control (ICC) with electronic stability control (ESC) and active rear steering (ARS). Direct yaw moment control is used to generate a control yaw moment. A weighted pseudo-inverse-based control allocation (WPCA) method is adopted to distribute the control yaw moment into tire forces, generated by ESC and ARS. Simulation-based tuning of variables weights in the WPCA is used to enhance the yaw moment distribution performance. Simulations using the vehicle simulation software $CarSim^{(R)}$ show that the proposed ICC is effective in improving maneuverability and lateral stability.

• Journal of Drive and Control
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• v.14 no.2
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• pp.9-15
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• 2017

The steering systems of all-terrain cranes have been developed with various control strategies for the stability and drivability. To optimally control the input steering angle, an accurate mathematical model that represents the actual crane dynamics is required. The derivation of an accurate mathematical model to optimally control the steering angle, however, is difficult since the steering-control strategy generally varies with the magnitude of the crane's longitudinal velocity, and the postures of the crane's working parts vary while it is being driven. To address this problem, this paper proposes an automatic steering-control algorithm that is based on the MPC (model predictive control) with a disturbance observer for all-terrain cranes. The designed disturbance observer of this study was used to estimate the error between the base steering model and the actual crane. A model predictive controller was used for the computation of the optimal steering angle, along with the use of the base steering model with an estimated uncertainty. Performance evaluations of the designed control algorithms were conducted based on a curved-path scenario in the Matlab/Simulink environment. The performance-evaluation results show a sound reference-path-tracking performance despite the large uncertainties.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.10
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• pp.949-958
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• 2012

Position tracking control of a link of a slave manipulator which needed to track the corresponding link of a master manipulator was addressed in this paper. Since driving torque from motor is transmitted through a set of flexible cable to link, the motion control system is modeled by a two-mass model connected with elastic coupling which has finite stiffness. Relative vibration of two-mass resonant system is a serious problem to operate manipulator. This paper proposed sliding mode control to reduce resonant vibration and fine position tracking control. Also, a pseudo-sliding mode control which uses a saturation function instead of a signum function was discussed and showed that the pseudo-sliding mode control can improve disturbance regulation performance as well as guarantees fine command tracking without chattering which is an inherent drawback of basic sliding mode control. In addition, a disturbance observer based sliding mode control has been suggested to improve disturbance regulation performance. The feasibility of the proposed control design was verified along with some simulation results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.500-505
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• 2009

This paper presents temperature control of engine cooling system using a controllable magnetorheological (MR) fan clutch. An appropriate size of MR fan clutch is devised and modeled on the basis of Bingham model. Subsequently, an optimization to determine design parameters such as width of housing is undertaken by choosing the reciprocal of the controllable torque as an objective function. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. A sliding mode controller is then designed to control the angular velocity of the MR fan clutch using experimentally determined parameters. The designed controller is experimentally implemented and control performances of the MR fan clutch system are evaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.51-57
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• 2010

This paper presents temperature control of engine cooling system using a controllable magnetorheological(MR) fan clutch. An appropriate size of MR fan clutch is devised and modeled on the basis of Bingham model. Subsequently, an optimization to determine design parameters such as width of housing is undertaken by choosing the reciprocal of the controllable torque as an objective function. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. A sliding mode controller is then designed to control the angular velocity of the MR fan clutch using experimentally determined parameters. The designed controller is experimentally implemented and control performances of the MR fan clutch system are evaluated.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.2
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• pp.123-130
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• 2000

Fuzzy control is proposed to regulate cutting force in turning operations under varying cutting conditions. The traditional linear controllers based on crisp mathematical model cannot effectively control cutting force becasue of the nonlinear dynamics of turning operations. The proposed fuzzy controller is based on operator experience and expert knowledge. The membership functions for the inputs and the output of the controller are designed. Cutting force is regulated by adjusting feedrate according to the variation of cutting conditions. The performance of the proposed controller is evaluated by experiments. The results of experiments show that the proposed fuzzy controller has a good cutting force regulation over a wide range of cutting conditions.

• Tribology and Lubricants
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• v.19 no.6
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• pp.335-341
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• 2003

Recently, the automotive industry is being developed rapidly. On this, a demand of high quality performance­test­machine is increased too. But it is progressive technology that must be combined hydraulic, mechanic and electronic technologies. To construct this system, the design of oil hydraulic circuit, interface skill between sensor and personal computer, data acquisition & display system and integrated control are very important skill. Moreover, reliable data is obtained with vacuum system and complex heat exchange system. Therefore, in this study, we designed a performance­test­machine by using above key technologies and we also made a integrated PC control system using personal computer which is more progressive and flexible method than PLC control.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.113-119
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• 2015

The technical development of electric vehicles has been actively proceeding because of the reduction of oil resources and need for eco-friendly vehicle technology. In particular, an electronic control unit is an important element in the technology of electric vehicles due to the motor drive system. This paper concerns an experimental study on the thermal analysis of the steering control ECU structure for an electric vehicle. The ECU unit is designed for eight heat sinks for the thermal analysis of the ECU structure. The thermal analysis characteristics of the ECU structure are evaluated by the temperature distribution, heat flow, von Mises stress, total translation, and external surface temperature measurement of the ECU unit.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1139-1143
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• 2003

HILS(Hardware-In-the-Loop Simulation) is a scheme that incorporates hardware components of primary concern in the numerical simulation environment. Due to its advantages over actual vehicle test and pure simulation, HILS is being widely accepted in automotive industries as test benches for vehicle control units. Developed in this study is a HILS system for EHB(Electro-Hydraulic Brake) systems that include a high pressure generator and a valve control system that independently modulates the brake pressures at four wheels. An EHB control logic was tested in the HILS system. Test results under various driving conditions are presented and compared with the VDC logic.