Modeling and control of a nonlinear half-vehicle suspension system: a hybrid fuzzy logic approach

Modeling and control of vehicle suspension system are high noteworthy from safety to comfort. In this paper, an analytical nonlinear half-vehicle model which is included quadratic tire stiffness, cubic suspension stiffness, and coulomb friction is derived based on fundamental physics. A hybrid fuzzy logic approach which combines fuzzy logic and PID controllers is designed for reducing the vibration levels of passenger seat and vehicle body. Performances of designed controllers have been evaluated by numerical simulations. Comparisons with classical PID control, Fuzzy Logic Control (FLC) and Hybrid Fuzzy-PID control (HFPID) have also been provided. Results of numerical simulations are evaluated in terms of time histories of displacement and acceleration responses and ride index comparison. A good performance for the Hybrid Fuzzy-PID controller with coupled rules (HFPIDCR) is achieved in simulation studies despite the nonlinearities.     

Seismic-vibration mitigation of a nonlinear structural system with an ATMD through a fuzzy PID controller

This paper discusses the design of fuzzy PID type controllers (FPIDC) to improve seismic control performance of a nonlinear structural system with an active tuned mass damper (ATMD) against earthquakes. Since structural systems have nonlinearities and uncertainties, fuzzy-based controllers are adequate because of their robust character and satisfactory performance in active structural control. The main advantages of this controller are the ability to handle nonlinearities and uncertainties effectively. In the literature, various structures for fuzzy PID (including PI and PD) controllers have been proposed. In order to obtain proportional, integral and derivative control actions altogether, it is intuitive and convenient to combine PI and PD actions to form a fuzzy PID controller. The simulated system has fifteen degrees of freedom and is modeled using nonlinear behavior of the base–structure interaction. The system is then simulated against the ground motion of the Northridge earthquake (M _w =6.7) in USA on 17 January, 1994. Finally, the time history of the storey displacements, accelerations, ATMD displacements, control voltage and frequency responses of both the uncontrolled and controlled cases are presented. The ground motion recorded of the El-Centro and Kocaeli earthquakes has been used to evaluate the effectiveness of the proposed control algorithm. The robustness of the controller has been checked through the uncertainty in stiffness of the structure. Simulation results exhibit that superior vibration suppression is achieved by the use of designed fuzzy PID type controllers.     

Sensor less fuzzy control of DC motor

This paper is concerned with the design of the sensorless controller for the position control of DC motor. The DC motor can be modeled as a linear time invariant single input single output system. In this paper synthesis and analysis of position control of a DC motor using sensor less fuzzy control and conventional PID controllers are carried out and their performance is evaluated and compared. The performance of sensor less fuzzy controller is found superior to conventional PID controllers even in the presence of disturbances.     

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在仿真研究1/4车体二自由度液压半主动悬架的基础上,设计了一种 用于1/2车体的液压半主动悬架的参数自整定模糊PID控制器,并利用模糊控制规则对 PID参数进行在线修改. 以正弦信号路面、脉冲信号路面和C级路面3种典型路面作为输入 信号,应用MATLAB/Simulink控制系统仿真软件对该半主动悬架模型进行的计算机仿真表明, 具有模糊PID控制器的半主动悬架在提高车辆乘坐的舒适性方面要明显优于一般的模糊控制 悬架,具有更好的自适应能力.     

New analytical method to evaluate the powerplant and chassis coupling in the improvement vehicle NVH

The design of an automotive powerplant mounting system is an essential part in vehicle safety and improving the vehicle noise, vibration and harshness (NVH) characteristics. One of the main problems encountered in the automotive design is isolating low frequency vibrations of the powerplant from the rest of the vehicle. The significant powerplant mass makes the choice of frequency and mode arrangements a critical design decision. Several powerplant mounting schemes have been developed to improve NVH properties concentrating on the positioning and design of resilient supports. However these methods are based on decoupling rigid body modes from a grounded powerplant model which ignores chassis and suspension system interactions. But it cannot be stated that decoupling the grounded rigid body modes of the powerplant will systematically reduce chassis vibrations. In this paper, a new analytical method is proposed to examine the mechanisms of coupling between the powerplant and the vehicle chassis and subsystems. The analytical procedure expands the equation of motion of the vehicle components to such that a domain of boundary conditions used in the 6 degrees-of-freedom powerplant mounting model can be defined. An example of this new procedure is given for improving NVH chassis response at idle speed using the torque roll axis decoupling strategy.     

Tuning of PID Controllers Based on Bode’s Ideal Transfer Function

This paper presents a new strategy for tuning PID controllers based on a fractional reference model. The model is represented as an ideal closed-loop system whose open-loop is given by the Bode’s ideal transfer function. The PID controller parameters are determined by the minimization of the integral square error (ISE) between the time responses of the desired fractional reference model and of the system with the PID controller. The resulting closed-loop system (with the PID controller) has the desirable feature of being robust to gain variations with step responses exhibiting an iso-damping property. Several examples are presented that demonstrate the effectiveness and validity of the proposed methodology.     

On the Testing of Vibration Performances of Road Vehicle Suspensions

Both a test rig and a method are presented for the indoor testing of vibration performances of road vehicle suspension systems. A suspension (corner) has been positioned on a rotating drum (2.6 m diameter) placed in the Laboratory for the Safety of Transport of the Politecnico di Milano. The suspension system is excited by means of cleats fixed to the working surface of the rotating drum. The forces and the moments acting at the suspension-chassis joints are measured in the frequency range 0–120 Hz. Five special six-axis load cells have been conceived, manufactured, calibrated and employed. Transient wheel motions have been recorded. The influence of the vehicle speed on the relevant vibration performance indexes has been assessed. An approach for the identification of the suspension damping characteristics is introduced. A full and accurate characterization of a vehicle suspension system has been performed.     

Load distribution control system design for a semi-track air-cushion vehicle

This paper describes the design principle for a semi-track air-cushion vehicle working on soft terrain. A novel structure, i.e., a flexible joint mechanism is designed for the semi-track air-cushion vehicle suspension system. Focusing on optimizing the total power consumption of the vehicle, three main issues were studied in this paper. First, a theoretical model for minimizing the total power demand of the vehicle is developed. The effects of load distribution on total rolling resistance and total power requirement are calculated which are compared with the prototype experiment data. Second, the optimization procedure is presented. Third, a control scheme is proposed to minimize the power consumption by using a self-tuning PID fuzzy controller and the feasibility was examined by the simulations performed in Matlab/Simulink software environment.     

Simulation and hybrid fuzzy-PID control for positioning of a hydraulic system

Accuracy and precision of position control of hydraulic systems are key parameters for engineering applications in order to set more economical and quality systems. In this context, this paper presents modeling and position control of a hydraulic actuation system consisting of an asymmetric hydraulic cylinder driven by a four way, three position proportional valve. In this system model, the bulk modulus is considered as a variable. In addition, the Hybrid Fuzzy-PID Controller with Coupled Rules (HFPIDCR) is proposed for position control of the hydraulic system and its performance is tested by simulation studies. The novel aspect of this controller is to combine fuzzy logic and PID controllers in terms of a switching condition. Simulation results of the HFPIDCR based controller are compared with the results of classical PID, Fuzzy Logic Controller (FLC), and Hybrid Fuzzy-PID controller (HFPID). As a result, it is demonstrated that Hybrid Fuzzy PID Controller with Coupled Rules is more effective than other controllers.     

Active vibration isolation of machinery and sensitive equipment using H ∞ control criterion and particle swarm optimization method

Isolating the sensitive equipment from vibrating base or the foundation from machinery vibration is of practical importance in a number of engineering fields. With the development of the vibration control techniques and increasing requirements for the higher-performance vibration isolation in industry and everyday life, active vibration isolation exhibits the best performances. In this paper, active vibration isolation reducing vibration transmitted from vibrating base to sensitive equipment and from machinery to foundation was investigated. Controller as static output feedback was considered to design components of active isolation system. An active control is provided by using H _∞ control criteria to design this controller. This criterion is presented as a cost function and then optimized by Particle Swarm Optimization (PSO) algorithm. The approach is validated using numerical simulation. Results show that this static output feedback H _∞ controller using PSO algorithm can get good performance to reduce the effect of unwanted vibration and disturbances.     

Robust adaptive speed control of uncertain hybrid electric vehicle using electronic throttle control with varying road grade

The design objective of this paper is to apply various control techniques to control the speed of a hybrid electric vehicle (HEV) using an electronic throttle control system (ETCS). The DC servo motor is used for controlling the angular position of the throttle valve. A proportional-integral-derivative (PID), a self-tuning fuzzy PID (STF-PID) controller and a model reference adaptive system (MRAS) with a sliding mode (SM) adaptation mechanism are used for controlling the speed of the nonlinear vehicle. The integral error performance indices (IEPI) such as the integral of the absolute error (IAE), the integral of the square of error (ISE) and the time domain performance specifications such as overshoot (OS), settling time (ST) and rise time (RT) are taken into consideration for the performance analysis of HEV. The robust H_∞ controller using mixed sensitivity approach is designed and implemented for the linearized HEV. The robust stability of uncertain HEV with H_∞ controller using Kharitonov’s theorem is analyzed, and the stability margin of the linearized vehicle system is determined. These control techniques are developed to achieve the robust performance of the throttle controlled HEV with the target to achieve a wide range of speed, fuel economy, reduced pollution and improved efficiency.     

Analysis of vibration and frequency transmission of high speed EMU with flexible model

When the operation speed of the high-speed train increases and the weight of the carbody becomes lighter,not only does the sensitivity of the wheel/rail contact get higher,but also the vibration frequency range of the vehicle system gets enlarged and more frequencies are transmitted from the wheelset to the carbody.It is important to investigate the vibration characteristics and the dynamic frequency transmission from the wheel/rail interface to the carbody of the high-speed electric multi-uint（EMU）.An elastic highspeed vehicle dynamics model is established in which the carbody,bogieframes,and wheelsets are all dealt with as flexible body.A rigid high-speed vehicle dynamics model is set up to compare with the simulation results of the elastic model.In the rigid vehicle model,the carbody,bogieframes and wheelsets are treated as rigid component while the suspension and structure parameters are the same as used in the elastic model.The dynamic characteristic of the elastic high speed vehicle is investigated in time and frequency domains and the di ff erence of the acceleration,frequency distribution and transmission of the two types of models are presented.The results show that the spectrum power density of the vehicle decreases from the wheelset to the carbody and the acceleration transmission ratio is approximately from 1%to 10%for each suspension system.The frequency of the wheelset rotation is evident in the vibration of the flexible model and is transmitted from the wheelset to the bogieframe and to thecarbody.The results of the flexible model are more reasonable than that of the rigid model.A field test data of the high speed train are presented to verify the simulation results.It shows that the simulation results are coincident with the field test data.     

Controlling the vertical shift of an isolated body based on the vibration of nonlinear systems with asymmetric damping forces

Asymmetric damping forces induce the equilibrium position of the isolated body to shift downward. Inspired by this phenomenon, this paper proposes the novel concept of shifting an isolated body based on the vibration of nonlinear systems with asymmetric damping forces. To verify the feasibility of this concept, a piecewise smooth isolation system is established. The incremental harmonic balance method is used to analyze the nonlinear vibration system and to obtain a steady-state analytical solution. The accuracy of the solution is verified by the Runge–Kutta method. Based on the analytical solution, the influences of some key parameters on the system vibration response are analyzed, revealing that the shift in the isolated body height increases with increasing excitation amplitude and damping asymmetry ratio. Additionally, this shift first increases and then decreases with increasing excitation frequency, reaching a peak near the natural frequency of the intermediate body. Finally, considering the complex structure, high energy consumption, and slow response of active suspension actuators, the proposed concept is applied to the tilt control of a vehicle. The simulation results show that the proposed methodology based on this concept can tilt a vehicle body to a certain angle in the turning direction, enabling the use of a semi-active actuator for vehicle tilt control to realize the control effect achieved by an active actuator.

     

静电陀螺支承控制的自适应逆控制分析

静电陀螺的支承控制系统中由于不可避免地存在建模不准确及对象扰动,传统的控制器设计只能在系统动态控制与对象扰动消除之间折衷。根据自适应逆控制的结构,利用模糊径向基函数神经网络进行对象建模、逆对象建模和扰动消除建模,设计了带扰动消除的自适应逆控制的八电极静电陀螺支承控制器。仿真表明,该控制器可以同时提高控制的精度和鲁棒性,在保证支承系统动态性能的同时,大大抵消对象扰动的影响,克服传统控制方法的折衷缺陷,对静电陀螺的自适应逆控制器的工程实现具有重要意义。     

Automated design of fractional PI QFT controller using interval constraint satisfaction technique (ICST)

In this paper, a fractional-order proportional-integral (FOPI) controller is proposed and designed for a class of nonlinear integer-order (IO) systems. For fair comparison, the proposed FOPI and the traditional integer-order PID (IOPID) controllers are designed following the same set of imposed tuning constraints, which can guarantee the desired control performance and the robustness of the designed controllers to the loop gain variations. This proposed design scheme offers a practical and systematic way of controller design for the nonlinear IO plant. We also propose a new and efficient method for automated synthesis of a fixed structure Quantitative Feedback Theory (QFT) FO controller. This is achieved by solving QFT quadratic inequalities of robust stability and performance specifications. The controller synthesis problem is posed as interval constraint satisfying problem (ICSP) and solved with interval constraint solver. The main feature of this method is that it guarantees to find all feasible controllers of given structure in the specified search domain. The designed FOPI and the traditional IOPID controllers are tested on the experimental setup designed by Educational Control Product (ECP) Magnetic Levitation Setup ECP 730. From the experimental results presented, it is observed that the designed FO controllers work more efficiently, with improved performance compared with the designed stabilizing IOPID controller.     

Performance evaluation of electronic control suspension featuring vehicle ER dampers

This paper presents ride comfort and driving stability performances of electronic control suspension (ECS) equipped with controllable electrorheological (ER) damper and appropriate control strategy. In order to achieve this goal, a cylindrical type ER damper which is applicable to Macpherson strut type suspension of a mid-sized passenger vehicle is designed and manufactured on the basis of the required damping force level of an existing passenger vehicle. After experimentally evaluating the field-dependent damping force and dynamic characteristics of the controllable ER damper, ECS consisting of sprung mass, spring, tire and controller is established in order to investigate the ride comfort and driving stability performances. On the basis of the governing equation of motion of the suspension system, five control strategies (soft, hard, comfort, sports and optimal mode) are formulated. The proposed control strategies are then experimentally realized with the quarter-vehicle ECS system. Control performances such as vertical acceleration of the car body and tire deflection are evaluated in both time and frequency domains under various road conditions. In addition, a comparative work is undertaken to investigate inherent control characteristics of each control strategy.     

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本文建立了二自由度1/4车体液压悬架的数学模型，介绍了利用模糊控制工具箱设计汽车液压半主动悬架模糊控制器的方法，通过应用MATLAB/Simulink对比仿真，得出了具有模糊控制器的液压半主动悬架的控制效果明显优于被动悬架，为半主动悬架在车辆上的应用提供了成功的范例。