• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.325-331
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• 2007

This paper proposed modelling and design method in suspension system design to analyze active suspension equipment by adopting active robust control theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. It is known that active suspension system is better than passive spring-damper system in designing suspension equipment. We analyze suspension system with considering location of front-rear wheel and driving velocity, then design control system. Numerical example is shown for validity of robust control system design in active suspension system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.86-92
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• 1993

자동차의 현가장치에 대한 능동제어연구는 국내외적으로 활발히 진행되어 왔다. 수동식현가장치는 단순히 스프링과 감쇠기로 차체의 진동을 수동 제어 하므로 성능 향상에 한계가 존재하게 된다. 수동식 현가장치가 강성계수와 감쇠계수를 조절함으로써 차체로 들어오는 진동을 억제하는 반면, 능동식제 어는 보통 유압을 이용하여 효율적으로 차체에 들어오는 진동을 억제시키게 된다. 일반적으로 자동차가 능동현가장치 설계시 요구되는 사항은 탑승자의 승차감, 조종성, 현가장치의 공간확보 문제, 경제성(제어력), 실제적으로 자동 차에 적용할 수 있는 능동제어기법인가 하는 문제이다. 자동차 능동식 현가 장치는 보통 1/4 car (2자유도계), Full-car 모델 (7자유도계) 등으로 모델링 을 하여 능동제어기를 설계한다. 1/4 car 모델의 특징은 해석이 비교적 단순 하고 현가장치의 동적거동을 이해하는데 유용하고 실험을 하거나 실제 자동 차에 적용하기 쉬운 반면에 Full-car 모델에 비해 제어력의 효율이 떨어진다 는 단점이 있다. 그 이유는 1/4 car 모델은 차체의 동역학적 특성을 고려하 여 설계하지 않았기 때문에 4개의 독립현가차축에서는 오직 그 현가축방향 으로 발생하는 수직방향의 진동만을 제어하기 때문이다. 따라서 동역학적 역 성에 기인하는 운동을 제어하는 비효율적인 제어력이 공급된다는 단점을 갖 는다. 이에 비해 full-car 모델은 주행모드(수직, 롤링, 피칭운동)간의 연성을 고려하여 제어기를 설계할 수 있기 때문에 1/4 car 모델에 비해 제어력의 효 율이 높다는 장점이 있는 반면에 모델이 수학적으로 복잡하므로 제어력을 구하는데 계산량이 많고, 실제 자동차에 적용하기에 복잡하다는 단점을 갖고 있다. 따라서 본 논문에서는 쉽게 실험할 수 있고, 실용화할 수 있는 1/4 car 모델에 대하여 능동제어기를 설계하여 실제자동차에 능동제어기를 적용할 때 참고가 될 수 있도록 하였다. 자동차는 저주파영역의 밴드통과필터 역할 을 하므로 저주파에서의 성능, 특히 탑승자가 민감하게 느끼는 0.5Hz - 10Hz 부근의 주파수성능은 승차감, 조종성에 상당히 중요하다. 이에 본 논문 에서는 0.5Hz - 10Hz 부근의 승차감, 조종성의 향상에 초점을 두고 차체의 속도를 출력변수로 한 LQG/LTR 제어기를 설계하였다. LQG/LTR 설계기법 은 안정도-강인성이 좋은 체계적인 설계기법으로서 전 상태를 측정할 필요 가 없으므로 실제 적용시 효과적이다. 또한 자동차의 제원의 변화에 대한 고 유치의 민감도해석과 새로운 개념으로 안정도-강인성(Robustness)해석을 하 여 수동시스템과 능동시스템의 강인성을 비교하였다.

• Journal of Industrial Technology
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• v.19
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• pp.31-42
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• 1999

This paper presents a method for evaluating the performance of a leaf spring suspension and an air spring suspension systems for trucks in terms of ride and handling. Leaf springs, which generally have non-linear progressive force-deflection characteristics, are modeled using beam and contact elements. The leaf spring analysis model shows good correlation with experimental results. Each component of an air spring suspension system, which is a single leaf, air spring, height control valve, compressor and linkages, is modeled appropriately. Non-linear characteristics of air spring are accounted for using the measured data, and pressure and volume relations for height control system is also considered. The wheel rate of the air suspension is taken lower but roll stiffness is taken higher than those of leaf springs to improve ride and handling performance, which is verified through driving simulations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1381-1388
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• 1993

This paper presents a method for the simultaneous optimal design of structural and control systems. Sensitivities of performance index with respect to structural design variables are analyzed. The structural design variables are optimized to minimize the performance index by use of conjugate gradient method. The method is applied to a half model of an active vehicle suspension system with elastic body moving on a randomly profiled road. The suspension control force of an optimally controlled system in the presence of measurement errors are calculated by use of linear quadratic Gaussian control theory and Kalman filter theory. The performance index contains ride comfort, road holding and working space of suspension. The structural design variables taken are stiffness, daming properties and the position of the suspension system. The random road profile considered as colored noise is shaped from white noise by use of shaping filter. The performance of an optimal simultaneous structure/control system is compared with that of an optimal controlled system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.769-774
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• 2006

This paper proposed a theoretic numerical modelling in control system design to analyze active suspension equipment by adopting minimum phase system theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. Transfer matrices of system with collocated sensors and actuators are symmetric. The symmetry is independent of the entities of mass, damping, or stiffness matrices, and is a non parametric nature. From this point of view, symmetric robust control system is analyzed and designed in this paper. Numerical example is shown for validity of robust control system design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1309-1316
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• 2002

The purpose of this study is to analyze the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type passenger vehicle. According to the results of simulation and the field test, Optimal condition was obtained for the stiffness ratio of the primary spring and the secondary of the suspension system. When the stiffness ratio was increased, the vibration was increased on the car body and decreased on the bogie, and ride quality are getting worse because of increase of the vertical natural frequency of the car body. The results of this study are usefull to improve the technology of the ride quality of KT-23 type vehicle.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1147-1152
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• 2006

This paper proposed modelling and design method in suspension system design to analyze sky hook damper system by adopting active robust control theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. It is known that sky hook suspension system is better than passive spring-damper system in designing suspension equipment. We analyze location of sensor and actuator in sky hook system and its motion equation, then design robust control system. Numerical example is shown for validity of robust control system design in active sky hook suspension system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.81-87
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• 2017

This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1110-1115
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• 2002

The purpose of this study is to analyze the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type passenger vehicle. According to the results of simulation and the small scale vehicle test. Optimal condition was obtained for the stiffness ratio of the primary spring and secondary spring of the suspension system. When the stiffness ratio was Increased, the vortical vibration was increased on the car body for empty and weight car. The result of this study are stable to use of the optimum parameter of the ride duality of KT-23 type vehicle. Also, it is usefull to development of full scale vehicle dynamomer

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.950-955
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• 2006

This paper prosed modelling and design method in suspension system sesign to analyze sky hook damper system by adopting active suspension control theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. It is hon that sky hook suspension system is better than passive spring-damper system in designing suspension equipment. We analyze location of damper in sky hook system and its motion equation then design robust control system. Numerical example is shown for validity of robust control system design in active sky hook suspension system.