DEVELOPMENT OF PREVIEW ACTIVE SUSPENSION CONTROL SYSTEM AND PERFORMANCE LIMIT ANALYSIS BY TRAJECTORY OPTIMIZATION

Minwoo Soh,Hyeongjun Jang,Jaehyung Park,Youngil Sohn,Kihong Park 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.6

The main role of the suspension system is to achieve ride comfort by reducing vibrations generated by the road roughness. The active damper is getting much attention due to its reduced cost and ability to enhance ride comfort especially when the road ahead is measurable by an environment sensor. In this study a preview active suspension control system was developed in order to improve ride comfort when the vehicle is passing over a speed bump. The control system consists of a feedback controller based on the skyhook logic and a feedforward controller for canceling out the road disturbance. The performance limit for the active suspension control system was computed via trajectory optimization to provide a measure against which to compare and validate the performance of the developed controller. The simulation results indicated that the controller of this study could enhance ride comfort significantly over the active suspension control system employing only the skyhook feedback control logic. Also the developed controller, by displaying similar control pattern as the trajectory optimization during significant time portions, proved that its control policy is legitimate.

MR 감쇠기를 이용한 구조물의 변형된 슬라이딩 모드 제어

민경원,정진욱 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.3

Semi-active control devices have received significant attention in recent Years because they offer the adaptability of active-control devices without requiring the associated large power sources. Magnetorheological(MR) dampers are semiactive control devices that use MR fluids to produce controllable dampers. This paper applies sliding mode control method using target variation rate of Lyapunov function for the control of structures by use of MR dampers. The three-story building model under earthquake excitation is analyzed by installing a MR damper in the first-story. The performance of semi-active controllers designed by clipped-optimal algorithm and modified sliding mode control algorithm is compared to the performance of passive-type MR dampers. The results indicate that semi-active controllers achieve a greater reduction of responses than passive-type system and especially the controller by modified sliding mode control method shows a good applicability in the view of response control and control force.

ESC, AFS와 AGCS를 이용한 샤시 통합제어시스템 설계

윤경준(Kyoungjun Yoon),이재천(Jaecheon Lee),이규훈(Kyuhoon Lee),황태훈(Taehun Hwang),박기홍(Kihong Park),허승진(Seung-Jin Heo) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The active chassis control systems have been developed with vehicle electronic technology by achieving operating convenience and guaranteeing the stability of the vehicle. However, each controller has been optimized to meet its object according as developing each controller. In this paper, two integrated control logics - one that integrates Electronic Stability Control and Active Geometry Control Suspension and the other that integrates Electronic Stability Control and Active Front Steering - have been developed. The main control target of both logics is vehicle dynamics control under critical situations. The two logics were tested under various driving conditions in a reliable simulation environment and their synergetic effects were investigated. The results indicate that the proposed logics can yield better vehicle performance than the cases when the individual chassis control modules work without any integration scheme.

Analog active valve control design for non-linear semi-active resetable devices

Geoffrey W. Rodgers,J. Geoffrey Chase,Sylvain Corman 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.5

Semi-active devices use the building\'s own motion to produce resistive forces and are thus strictly dissipative and require little power. Devices that independently control the binary open/closed valve state can enable novel device hysteresis loops that were not previously possible. However, some device hysteresis loops cannot be obtained without active analog valve control allowing slower, controlled release of stored energy, and is presents an ongoing limitation in obtaining the full range of possibilities offered by these devices. This in silico study develops a proportional-derivative feedback control law using a validated nonlinear device model to track an ideal diamond-shaped force-displacement response profile using active analog valve control. It is validated by comparison to the ideal shape for both sinusoidal and random seismic input motions. Structural application specific spectral analysis compares the performance for the non-linear, actively controlled case to those obtained with an ideal, linear model to validate that the potential performance will be retained when considering realistic nonlinear behaviour and the designed valve control approach. Results show tracking of the device force-displacement loop to within 3-5% of the desired ideal curve. Valve delay, rather than control law design, is the primary limiting factor, and analysis indicates a ratio of valve delay to structural period must be 1/10 or smaller to ensure adequate tracking, relating valve performance to structural period and overall device performance under control. Overall, the results show that active analog feedback control of energy release in these devices can significantly increase the range of resetable, valve-controlled semi-active device performance and hysteresis loops, in turn increasing their performance envelop and application space.

ActiveX Control 취약점 검사 및 검증 기법 연구

김수용(Su Yong Kim),손기욱(Kiwook Sohn) 한국정보보호학회 2005 정보보호학회논문지 Vol.15 No.6

최근 웹 사이트들은 HTML과 스크립트 언어의 한계를 뛰어넘어 사용자에게 다양한 서비스를 제공하기 위해 많은 ActiveX Control들을 배포하고 있다. 하지만, ActiveX Control은 웹 페이지나 이메일을 통해 실행될 수 있기 때문에 안전하지 못한 ActiveX Control은 개인 PC 보안에 치명적인 약점이 될 수 있다. 그럼에도 불구하고 대부분의 ActiveX Control들은 안전성에 대한 검증 없이 사용자들에게 배포되고 있어 많은 개인 PC들이 외부의 침입에 노출되고 있다. ActiveX Control의 취약점을 줄이기 위해서는 제 3자에 의한 취약점 검사와 검증이 필요하다. 본 고에서는 점검대상 식별부터 Reverse Engineering까지 ActiveX Control 의 취약점 검사를 수행하기 위한 절차와 관련 기술들에 대해 기술한다. 또한 ActiveX Control의 경우 일반 응용프로그램과 다를 뿐만 아니라 국내 환경과 국외환경의 차이로 인해 기존의 취약점 검증 기법들을 그대로 적용할 수 없다. 본 고에서는 ActiveX Control의 취약점 검증을 위해 필요한 요소기술들에 대해 기술한다. To provide visitors with the various services, Many web sites distribute many ActiveX controls to them because ActiveX controls can overcome limits of HTML documents and script languages. However, PC can become dangerous if it has unsecure ActiveX controls, because they can be executed in HTML documents. Nevertheless, many web sites provide visitors with ActiveX controls whose security are not verified. Therefore, the verification is needed by third party to remove vulnerabilities in ActiveX controls. In this paper, we introduce the process and the technique to find vulnerabilities. The existing proof codes are not valid because ActiveX controls are different from normal application and domestic environments are different from foreign environments. In this paper, we introduce the technique to prove vulnerabilities in ActiveX control.

차량의 동적 성능 향상을 위한 Active Roll Control Stabilizer Bar와 Continuous Damping Control의 통합 제어에 대한 연구 Part Ⅱ

이강원(Kangwon Lee),이종일(Jongil Lee),김영우(Youngwoo Kim),오승규(Seungkyu Oh),노지훈(Jihoon Roh),정명철(Myoungchul Jung),김인동(Indong Kim),장진희(Jinhee Jnag) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

Generally, the vehicle dynamics performance is influenced each chassis subsystem with some trade-off relations. One of the systems is a suspension system that related vehicle ride and handling performance. Especially the roll stiffness tendency of a vehicle can be significantly changed, if the suspension component is actively controlled. This study is presented the Active Roll Control Stabilizer Bar System (ARC) for improving of the vehicle roll motion and vehicle dynamic performance by control of roll stiffness distribution. This paper describes a fundamental understanding of the theory and application of the ARC system analysis. Based on the study on ARC, we can make a proposal on the integrated control system using Continuous Damping Control (CDC) and Active Roll Control stabilizer bar (ARC). This research arranges and defines the ARC functionality and performance limits, then shows how to improve such a limit using by CDC (Continuous Damping Control) on the vehicle performance with ARC system. Finally, this paper proposes the vehicle dynamics performance integration control strategy and show the synergy effect through the integrated control vehicle simulation.

Integration of Active Tilting Control and Full-Wheel Steering Control System on Vehicle Lateral Performance

Liang Wu,Ahmac Ejaz,KHAN MUHAMMAD ARSHAD,윤일중 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.4

This research presents an integration of two control systems, an active tilting controller and a full-wheel steering controller. This integration improves vehicle lateral performances by enhancing road-holding capability, lateral stability, and safety simultaneously. The active tilting controller utilizes an active mass shift to evenly distribute the vertical load at each suspension, and boost road-holding capability. On the other hand, the full-wheel steering controller adjusts rear steering angles to use lateral force at each ground-tyre contact point and amplify the vehicle’s ability to follow the desired yaw rate and global sideslip angle during cornering maneuvers. Considering the improved road-holding capability and the coupling effect of body attitude motion and yaw motion, the two controllers in combination produce a synergistic effect on ride comfort, maneuverability and safety, and improve overall lateral performance. A 7-degree-of-freedom (DOF) linear full car model is used in designing the active tilting controller, while a 2-DOF bicycle model considering the attitude motion of the car body is used in designing a full-wheel steering controller. A 14-DOF complex nonlinear full car model that can truly reflect 6-DOF car body motion is applied to verify the performance of the proposed collaborative system. The simulation results show that the system represents a better lateral stability and steering response in intense driving while ensuring the better heading directivity of the vehicle.

Feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity

Ashok K. Bagha,Subodh V. Modak 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.3

This paper presents and compares three feedback control strategies for active control of noise inside a 3-D vibro-acoustic cavity. These are a) control strategy based on direct output feedback (DOFB) b) control strategy based on linear quadratic regulator (LQR) to reduce structural vibrations and c) LQR control strategy with a weighting scheme based on structural-acoustic coupling coefficients. The first two strategies are indirect control strategies in which noise reduction is achieved through active vibration control (AVC), termed as AVC-DOFB and AVC-LQR respectively. The third direct strategy is based on active structural-acoustic control (ASAC). This strategy is an LQR based optimal control strategy in which the coupling between the various structural and the acoustic modes is used to design the controller. The strategy is termed as ASAC-LQR. A numerical model of a 3-D rectangular box cavity with a flexible plate (glued with piezoelectric patches) and with other five surfaces treated rigid is developed using finite element (FE) method. A single pair of collocated piezoelectric patches is used for sensing the vibrations and applying control forces on the structure. A comparison of frequency response function (FRF) of structural nodal acceleration, acoustic nodal pressure, and piezoelectric actuation voltage is carried out. It is found that the AVC-DOFB control strategy gives equal importance to all the modes. The AVC-LQR control strategy tries to consume the control effort to damp all the structural modes. It is seen that the ASAC-LQR control strategy utilizes the control effort more intelligently by adding higher damping to those structural modes that matter more for reducing the interior noise.

An innovative hardware emulated simple passive semi-active controller for vibration control of MR dampers

Zhang, Jianqiu,Agrawal, Anil K. Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.3

Magneto-Rheological (MR) dampers are being used increasingly because of their adaptability to control algorithms and reliability of passive systems. In this paper, an extensive investigation on performance of MR dampers in semi-active and passive modes has been carried out. It is observed that the overall energy dissipation by MR dampers in passive-on modes is higher than that in semi-active modes for most of the competitive semi-active controllers. Based on the energy dissipation pattern, a novel semi-active controller, termed as "Simple Passive Semi-Active Controller", has been proposed for MR dampers. This controller can be emulated by a simple passive hardware proposed in this paper. The proposed concept of controller "hardware emulation" is innovative and can also be implemented for other semi-active devices for control algorithms of certain form. The effectiveness and reliability of the proposed controller has been investigated extensively through numerical simulations. It has been demonstrated that the proposed controller is competitive to or more effective than other widely used / investigated semi-active controllers.

Motorized vehicle active suspension damper control with dynamic friction and actuator delay compensation for a better ride quality

Shin, Donghoon,Lee, Geesu,Yi, Kyongsu,Noh, Kihan Professional Engineering Publishing Ltd 2016 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>This paper describes motorized active suspension damper control with dynamic friction and actuator delay compensation for an enhanced ride quality. The control algorithm consists of a supervisory controller, an upper-level controller and a lower-level controller. The supervisory controller determines the control modes, such as the passive control modes and the active control mode. The upper-level controller, which incorporates the existing actuator delay, computes the damping force using linear quadratic control theory. The actuator input is determined by the lower-level controller by compensating the dynamic friction torque. To estimate the sprung-mass displacement, the sprung-mass velocity, the unsprung-mass displacement and the unsprung-mass velocity, two state estimators are proposed. An adaptive observer is developed for the non-linear dry friction to estimate the ball-screw dynamic friction caused by the axial movement of the actuator and the viscosity. The performance of the proposed control algorithm was evaluated from simulations. It was shown from simulations that the proposed motorized active suspension damper control with a friction and delay compensation algorithm can improve the ride quality.</P>