Improved optimal sliding mode control for a non-linear vehicle active suspension system

Chen, S.A.,Wang, J.C.,Yao, M.,Kim, Y.B. Elsevier [etc.] 2017 Journal of Sound and Vibration Vol.395 No.-

<P>The objective of this study is to present an improved optimal sliding mode (SM) control method for non-linear active suspension systems to obtain both the true nominal optimal suspension performance and better robustness. A general non-linear suspension dynamics model is established first. Its non-linear control scheme is applied using the improved optimal SM control method. This non-linear active suspension control system is linearized utilizing the feedforward and feedback linearization method. A fact is theoretically discovered that the general optimal SM control for the linearized active suspension system cannot provide true optimal results. Thus, the improved optimal SM controller for the linearized active suspension is proposed to address the disadvantage's of the general optimal SM controller. The improved optimal SM controller is designed by constructing an augmented optimal sliding mode manifold function, which includes all of the information of the structure and expected performance of the suspension. The advantages of the proposed controller are illustrated by comparing the performance of the improved optimal SM control, the fuzzy logical SM control, and the passive suspension. The simulation results verify that the proposed improved optimal SM control achieve the true nominal optimal suspension performance for a non-linear active suspension system in general condition. The results also show that even if the structure parameters and/or running conditions change, the proposed improved optimal SM control can still provide more robust characteristics. (C) 2017 Elsevier Ltd. All rights reserved.</P>

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.

Research on Self‑Learning Fuzzy Control of Controllable Excitation Magnetic Suspension Linear Synchronous Motor

Yunpeng Sun,Yipeng Lan 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2

This paper studies the problem of diferent parameters adjustment and poor anti-interference capability for the magnetic suspension control system of controllable excitation linear synchronous motor (CELSM). Based on operating mechanism of CELSM, the mathematical model of magnetic suspension system is established. In addition, based on the Takagi–Sugeno fuzzy model-based approach, a self-learning fuzzy controller with parameter adjustment mechanism is designed. The controller includes a reference model that displays the desired characteristics of the magnetic suspension control system, a fuzzy inverse model that adjusts the fuzzy rules in real time and reduces the errors between the reference model output and the system output to zero, the rules and parameters adjustment units that change the adjustment degree of the rules according to the output proportion factor of the fuzzy inverse model, and the errors between the system output and the reference model output. A self-learning mechanism for modifying the output value of a standard fuzzy controller. At last, the simulation model is set up and compared with other control methods, the result shows that the suspension height control system has better anti-interference ability and tracking efect under the self-learning fuzzy control strategy, as well as the ability to deal with the change of the internal parameters of the magnetic suspension system. And the feasibility and the superiority of the modifed control method are verifed.

DEVELOPMENT OF A CONTROL METHOD FOR AN ELECTROMAGNETIC SEMI-ACTIVE SUSPENSION RECLAIMING ENERGY WITH VARYING CHARGE VOLTAGE IN STEPS

S. A. CHEN,X. LI,L. J. ZHAO,Y. X. WANG,김영배 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.5

A system of electromagnetic semi-active suspension reclaiming energy (ESASRE), with an novel control varying charge voltage in steps (CVCVIS) based optimal integrated controller, is newly proposed to improve ride comfort and energy reclaiming. The proposed CVCVIS is built by changing the number of battery packs. The dynamic model of the semiactive suspension reclaiming energy is established first, which fully accounts for the non-linear characteristics of the damping actuator reclaiming energy (DARE). The parameters of DARE are decided by a compromise between ride comfort and manufacturing cost, with consideration of installation convenience. A integrated control system for ESASRE includes a controller for calculating the real-time ideal control force based on optimal linear quadratic Gaussian (LQG) control and the other for calculating the number of charging batteries to obtain the real-time actual control force using the proposed quasilinear relation function. Performance comparisons are implemented using three suspension types: ESASRE, the passive suspension, and the ideal active suspension. The performance index of ESASRE is 19.8% lower than that of the passive suspension, and 3.82% higher than that of the active suspension. With ESASRE, the power flowing into the battery pack accounts for 77.72% of the total vibration energy absorbed by DARE.

Comparative Evaluation on Effective Number of Active Suspension Actuators for Tracked Vehicle

David. O. Afamefuna,Rodrigue Tchamna,Iljoong Youn 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

The effective number of actuators required to control a tracked vehicle active suspension system based on a half vehicle model is studied. A two dimensional and two degree-of-freedom (2-DOF) linearized tracked vehicle model and several representations of road surface conditions, including haversine (bump/hole) and random road profile (RMS 2_09㎝) models are used in the simulation and analysis. The main goal of this research is to discover how to optimize the energy and cost required for effective control of tracked vehicle suspension systems, while maintaining closely approximated dynamic performance. The suspension systems are optimized with respect to ride comfort preference and suspension rattle space as expressed by the mean-squarevalues of body accelerations and suspension deflections. The dynamic performance and power demand of the active suspension system for a tracked vehicle with respect to six and two control actuators are evaluated and compared with each other and with that of a passive system using numerical simulation in time and frequency domain respectively. The results show that the dynamic performance for the active suspension system with two control actuators nearly follows that with six control actuators, while conserving a power demand of about one fifth that of the total power demand from the six control actuators. The strategy proposed here is taking full advantage of the fact that the systems in question, have only a two degree-of-freedom which means two controllers instead of six controllers is sufficient to obtain adequate system control. Frequency response curves to two types of road inputs, such as heaving and pitching, confirms the time domain response and also demonstrates the effectiveness of the two controllers’ suspension system on ride comfort. In addition, the effects of the six and two variable dampers on a semi active suspension system are also examined in this research.

Control of the motorized active suspension damper for good ride quality

Seo, Jongsang,Shin, Donghoon,Yi, Kyongsu,Yim, Seongjin,Noh, Kihan,Choi, Hyungjeen SAGE Publications 2014 Proceedings of the Institution of Mechanical Engin Vol.228 No.11

<P>This paper presents a control algorithm for the motorized active suspension damper. The control algorithm consists of supervisory, upper-level and lower-level controllers. The supervisory controller determines the control modes, such as the passive mode, the roll mode and the body acceleration mode. The upper-level controller computes the damping force using linear quadratic control theory. The actuator input is determined by the lower-level controller. Three state estimators, namely the vehicle body’s velocity estimator, the suspension state estimator and the friction estimator, are proposed to estimate the sprung-mass and unsprung-mass velocities, the tyre deflection, the roll angle, the roll rate and the friction. The performance of the proposed control algorithm was evaluated via simulations and vehicle tests. It was shown from both simulations and vehicle tests that the proposed control algorithm can improve the ride quality using a motorized active suspension damper.</P>

새로운 적응복합제어기를 이용한 MR 시트현가장치의 진동제어

한철희(Chulhee Han),최승복(Seung-Bok Choi),이태훈(Tae-Hoon Lee),안진희(Jin-Hee An) 한국소음진동공학회 2018 한국소음진동공학회 논문집 Vol.28 No.3

In this work, a new adaptive composite controller is designed and applied to vibration control of a magneto-rheological (MR) damper based seat suspension. The proposed controller consists of the interval type 2 fuzzy model, sliding mode controller and adaptive controller. After formulating the composite controller associated with adaptation laws, a robust stability is solidly proved using the Lyapunov stability criterion. Subsequently, its effectiveness is demonstrated by implementing it to the vibration control of a vehicle seat suspension associated with MR damper. Vibration control performances are evaluated at two different road profiles; regular bump and random wave road. It is experimentally shown that the proposed controller can provide better vibration control performances than a comparative composite controller showing lower level of the displacement and acceleration at the driver position.

압력 조절 밸브의 진동 제어를 통한 전자제어 서스펜션의 하중 안정화 연구

최원준(Wonjun Choi) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

The purpose of this paper is to study the stabilization of the force generated by the suspension (Hereinafter, referred to as damping force) which is applied with hydraulic control valve by electronic control by controlling the pressure with a variable magnetic force through a solenoid of a suspension. (Hereinafter, referred to as an Electric Control Damper) To this, hydraulic control valve was analyzed in terms of the structure and fluid flow, and results were derived through an experiment. The electronic control damper has a key mechanism for recognizing a condition of road surface to change the magnetic force of the solenoid through the current control and control the pressure by using the damping force required for controlling the behavior of the vehicle body according to the situation. Accordingly, the purpose of this study is to analyze and consider the effects of a magnetic force rapidly changing according to a situation on a pressure system. For stable pressure part control, the spring was set as a control factor through governing equation of pressure control mechanism, and the design and applicable coil spring stiffness values were verified through analysis and experiment. In this study, in addition to examining the operation of the suspension, it was applied to mass-produced vehicles, and a comparative test was conducted on the effect of stable damping force control on the actual vehicle to evaluate and confirm the effect of operating vibration.

Fractional-order control of active suspension actuator based on parallel adaptive clonal selection algorithm

Xubin Dong,Dingxuan Zhao,Bin Yang,Chenghao Han 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.6

In current study, a new approach for vehicle active suspension actuator control is reported. For this approach, a nonlinear model for an electro-hydraulic servo actuator and quarter suspension system is established. An Oustaloup recursive approximation (ORA) Fractionalorder proportional–integral–derivative (FOPID) controller is designed to control the displacement of the actuator, and controller parameters are optimized based on error integral criteria using the Parallel adaptive clonal selection algorithm (PACSA). The research indicates that PACSA can tune parameters of the FOPID controller accurately and efficiently, and the tuned FOPID controller performs better in terms of response speed and tracking accuracy than a regular Proportional–integral–derivative (PID) controller. The performance of the active suspension system that uses the FOPID actuator is obviously superior to that of the active suspension system that uses a PID actuator and a passive suspension system.

Robust Control Strategy of Heavy Vehicle Active Suspension Based on Road Level Estimation

Mingde Gong,Xin Yan 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.1

A new adaptive robust control strategy based on road level estimation for heavy rescue vehicles is proposed in this study. Firstly, a new road estimation method that considers the interaction between roads and vehicles is presented as a means of road level detection. A relative roughness indicator caused by different road levels is used as a basis for estimation. T–S fuzzy controller is designed to estimate the final road level. Secondly, an adaptive optimal H∞ controller is established by selecting the corresponding parameter matrix based on an estimated road level. A robust control strategy is formulated to calculate the control force that can realise the adaptive control of an active suspension when driving on different road levels. Finally, experiment results show that an active suspension control system based on road level estimation can adaptively control suspension stiffness and damping by adjusting the parameter matrix of a robust controller. The proposed control strategy can improve ride comfort and handling stability in different road levels.