Half Car Research Articles

Modelling and analysis of vehicle-structure-road coupled interaction considering structural flexibility, vehicle parameters and road roughness

To determine the dynamic forces acting on vehicle components a vehicle-structure-road interaction is considered. Coupled interaction was modelled using a flexible bridge-like thin beam structure with four and six Degree of freedom (DOF) half car models. In addition to the flexible structure, the road conditions were added to the model as random and non-random surface irregularities. A coupled equation of motion of the whole system was derived using Lagrange equations, and converted to a first-order state-space equation and then solved using the fourth-order Runge-Kutta method. Besides the dynamic forces, the effects of the vehicle speed, bridge flexibility, tire stiffness, random or non-random road irregularities on the passenger comfort are widely investigated. The results obtained were compared by several early VBI (Vehicle-bridge-interaction) studies in the literature and proved accurate with a 5 % difference.

The Investigation of a Ride Quality of Nonlinear Half-Car Model

The paper discusses the ride quality response of a half car model when a bilinear model and a power law model were implemented in the suspension of half car vehicle. The models were subjected to a step and double pothole disturbances. The nonlinearity of the model is contributed by the power law damper models which are located both at the front and at the rear of the vehicle. Passenger car dampers were initially tested on the damper test bench where the dynamic characteristics were obtained. From the experimental results it clearly showed that the automotive damper behaves nonlinearly. From the force-velocity graphs a backbone model was then developed and plot. Based on this graph two types of non-parametric model namely the bilinear model and power law model were then obtained through the Lavenberg-Marquardt curve fitting algorithm (LMA) method. From the multibody system simulations they clearly showed that the bounce and pitch responses of the bilinear damper model illustrates an overestimations of responses compared to the nonlinear damper model which may lead to a less accurate representation of a realistic damper.

Analysis of MR Damper for Quarter and Half Car Suspension Systems of a Roadway Vehicle

Magnetorheological (MR) dampers are evolving as one of the most promising devices for semi-active vibration control of various dynamic systems. In this paper, the suspension system of a car using MR damper is analysed for 2DOF quarter car and 4DOF half car models and then compared with corresponding suspension system using passive damper for ride comfort and handling. Magnetorheological damper is fabricated using a MR fluid of Carbonyl iron powder and Silicone oil added with additive. Experiments are conducted to establish the behaviour of the MR damper and are used to validate Spencer model for MR damper. Further, using the validated Spencer model of MR damper, the quarter car and half car models of Vehicle Suspension system are simulated by implementing a semi-active suspension system for analysing the resulting displacement and acceleration in the car body. The ride comfort and vehicle handling performance of each specific vehicle model with passive suspension system are compared with corresponding semi-active suspension system. The simulation and analysis are carried out using MATLAB/SIMULINK.

<b>Estimation of tracked vehicle suspension parameters

This work aims to estimate the suspension stiffness and damping coefficient of a tracked vehicle by using an inverse problem technique based on Particle Swarm Optimization (PSO) and on Random Restricted Window (R2W). The tracked vehicle has ten road wheels. Each road wheel is linked to a passive and independent suspension. A half car model with seven degrees of freedom describes the bounce and pitch dynamics of the chassis and the vertical dynamics of the wheels. Bounce and pitch accelerations are evaluated when the vehicle traverses a bump terrain. The inverse problem approach minimizes the total quadratic error between estimated and pseudo-experimental data for bounce and pitch accelerations. The viability of a field experiment to estimate the suspension parameters is analyzed, as well as the performance of the employed optimization methods and the effects of the noise on pseudo-experimental data.

IRI Estimation by the Frequency Domain Analysis of Vehicle Dynamic Responses

Smartphone based Dynamic Response Intelligent Monitoring System (iDRIMS) was developed to evaluate International Roughness Index (IRI) based on dynamic responses of ordinary vehicles [1]. However, the robustness and accuracy were limited. In this paper, iDRIMS is improved mainly by employing frequency domain analysis. The algorithm consists of two steps. The first step is to identify the vehicle model and the second step is to estimate the IRI by utilizing the identified vehicle model. In the first step, a half car (HC) model is selected as the vehicle model and its parameters are identified. The vehicle parameters are identified through a drive tests over a portable hump with a known size. As opposed to previous approach in the time domain using Unscented Kalman filter, the parameters are optimized to minimize the difference between simulation and measured hump responses in the frequency domain using genetic algorithm (GA). IRI is then estimated by measuring acceleration responses of ordinary vehicles. Measured acceleration is converted to the acceleration RMS of the sprung mass of standard quarter car by multiplying a transfer function. The transfer function, estimated through the simulation of the identified HC model as opposed to a QC model in previous approaches, reflects the vehicle pitching motions and sensor installation location. The RMS is further converted to IRI. Numerical simulation is conducted to investigate the IRI estimation performance in terms of various drive speeds and sensor locations. Experiment is carried out at a 13km road. Inacurate IRI estimation at speed change section is invesigated and compensated. Results from both simulation and experiment indicate that the proposed method accurately estimate IRI with high robustness and efficiency.

Performance Analysis of Half Car Suspension Model with 4 DOF using PID, LQR, FUZZY and ANFIS Controllers

The suspension system helps to enhance the ride quality, steering stability, passenger comfort and NVH. In this paper, using a half car active suspension model with 4 Degrees Of Freedom (4 DOF) the controllers such as Proportional Integral Derivative, Linear Quadratic Regulator, Fuzzy and Adaptive Neuro Fuzzy Inference System (ANFIS) are designed using MATLAB-Simulink. The response of these controllers has been analysed using the random road profile (ISO 8608) against the conventional passive suspension system. The results indicate that ANFIS based controller performs better on the parameters ‘Settling Time’ and ‘Amplitude’ of the road disturbances, compared with other controllers.

Pareto Optimization of a Half Car Passive Suspension Model Using a Novel Multiobjective Heat Transfer Search Algorithm

Most of the modern multiobjective optimization algorithms are based on the search technique of genetic algorithms; however the search techniques of other recently developed metaheuristics are emerging topics among researchers. This paper proposes a novel multiobjective optimization algorithm named multiobjective heat transfer search (MOHTS) algorithm, which is based on the search technique of heat transfer search (HTS) algorithm. MOHTS employs the elitist nondominated sorting and crowding distance approach of an elitist based nondominated sorting genetic algorithm-II (NSGA-II) for obtaining different nondomination levels and to preserve the diversity among the optimal set of solutions, respectively. The capability in yielding a Pareto front as close as possible to the true Pareto front of MOHTS has been tested on the multiobjective optimization problem of the vehicle suspension design, which has a set of five second-order linear ordinary differential equations. Half car passive ride model with two different sets of five objectives is employed for optimizing the suspension parameters using MOHTS and NSGA-II. The optimization studies demonstrate that MOHTS achieves the better nondominated Pareto front with the widespread (diveresed) set of optimal solutions as compared to NSGA-II, and further the comparison of the extreme points of the obtained Pareto front reveals the dominance of MOHTS over NSGA-II, multiobjective uniform diversity genetic algorithm (MUGA), and combined PSO-GA based MOEA.

The Simulation of The Influence of Surface Irregularities in Road Pavements on The Response of The Bridge to Moving Vehicle

The surface irregularities in the road pavement cause kinematic excitation of the moving vehicle. It leads to a significant increase of the dynamic load exerted on the road structures as well as on the bridge structures. There is used a home-made contact algorithm based on the Newmark scheme to create a numerical simulation of the vehicle-bridge interaction. The beam elements are used to create the model of the bridge and the vehicle is defined as a multi-body system that has characteristics of a half car model. The presented results of the numerical simulation that involves the irregularities show how the response of the bridge changes if there are used different random road roughness profiles. The roughness profiles that are used in the simulation are generated with consideration of the classification ISO 8608 Standard. The results of the simulations are also compared with the results obtained from the simulation where the roughness of the profile measured with the 3D scanner is used. This comparison shows that employment of the generated profile with the same classification as the measured one gives slightly different results.

Investigation of the energy recuperation potential of the damper system for a compact class passenger car

In this paper an investigation of the potential of harvesting the energy dissipated by shock absorbers is presented, with a special focus on compact-class passenger cars, representative of electric vehicles (EVs). The calculations include the pitch movement due to the acceleration of the vehicle. The road roughnesses are modelled according to DIN ISO 8608. The vehicle model considered is a half car model. The tyre model considers the damping and the absorption behaviour via an integrative filter. A large number of driving cycles are studied by using their predefined velocity profiles, including the NEDC the FTP75, and different city cycles like the NYC-cycle, and the Tokyo City cycle. The road roughnesses are projected onto the driving cycle profiles. The simulation results show the potential for energy harvesting systems for different road roughnesses and driving cycles. Parameter studies are conducted to study the influence of different factors on the harvestable energy.

Investigation of the energy recuperation potential of the damper system for a compact class passenger car

In this paper an investigation of the potential of harvesting the energy dissipated by shock absorbers is presented, with a special focus on compact-class passenger cars, representative of electric vehicles (EVs). The calculations include the pitch movement due to the acceleration of the vehicle. The road roughnesses are modelled according to DIN ISO 8608. The vehicle model considered is a half car model. The tyre model considers the damping and the absorption behaviour via an integrative filter. A large number of driving cycles are studied by using their predefined velocity profiles, including the NEDC the FTP75, and different city cycles like the NYC-cycle, and the Tokyo City cycle. The road roughnesses are projected onto the driving cycle profiles. The simulation results show the potential for energy harvesting systems for different road roughnesses and driving cycles. Parameter studies are conducted to study the influence of different factors on the harvestable energy.

Theoretical Study of Suspension System for Two-Dimensional Model of the Vehicle and its Effects on limiting speed and Driver Comfort

Vibration in cars is undesirable because it causes discomfort to passengers, and can also lead to fatigue and failure of some parts of the vehicle. Therefore, the study and analysis of comments movements cart embedded in ever to research vehicles since the invention. And associated vibration cart passenger comfort, safety and stability of the vehicle. The researchers analyzed several vibration of vehicles by looking at different models, such as quarter wagon model ,and Half Car Model and full vehicle model with different types of excitement experienced by the vehicle and intended here excitement is a set of external forces arising from the terrain. This research includes a half vehicle linear model , written for four degrees of freedom plus one (4 +1 DOF) after addition degree of freedom which is driver / passenger seat system becomes a five degrees of freedom, also the vehicle body is assumed as a rigid body and taking into account the Bounce and Pitch. The system governing equations of motion are formulated by using the finite element method (FEM). A Fortran language computer program has been established for this purpose and used in the process covering (Simulation) and stand on the performance evaluation and analysis riding cart at the design stage and stand on the impact driver way through a study on the subject and the quality of the driver's seat, Two criterion of standards of comfort has been used, such as standard rate of absorbed energy (Average Absorbed Power) to be the norm over the driver comfort or not. And the comfort factor which is the vertical acceleration root mean square is used as an indication for the ride comfort. In factthe driver is the most important link in the process of using vehicles because the decision-maker and dominant direct the movement of vehicle.

Self-tuning PID controller design using fuzzy logic for half car active suspension system

A car active suspension system plays an imperative role in adequately guaranteeing the stability of the car, retaining the continuous road wheel contact and improving the suspension performances. In this paper, Proportional Integral Derivative (PID), fuzzy logic and $$\hbox {H}\infty $$ controllers are used to control the car suspension system based on half car model. Moreover, a self-tuning PID controller based on fuzzy logic is developed to improve the performance of the system. The proposed structure overcomes the difficulty of having suitable responses in controlling the process in all conditions, especially when the system parameters are changing. The controllers are designed based on the mathematical model of the system. Through the proposed method, suspension working space is minimized and the best comfort of the driver is achieved. The comparison between simulation results demonstrates that by applying the presented method, the performance of the suspension system will be improved significantly.

Beam response analysis of moving vehicle with half car modeling

There were several tragedies concerning damages of bridge which seem to be sooner than the predicted period. One of hypothesis in this situation is an addition of vibration caused by long vehicle such as super long truck which has huge force transferred into the bridge and its long body causes more vibration due to phase difference of front and rear tire. The selected method which is used in this problem is using a simulation for modeling a bridge- vehicle system using half car vehicle model. The simulation is done using ANSYS Workbench 15.0 with some variation such us the thickness of beam and its supports. There are 3 kind of variation used in the thickness variety which are 2 m, 1 m, and 0.5 m. While in supports variation, we have fixed support, knife-edge support, and slider support. The results show that there is addition of vibration caused by long vehicle. It is proved by an oscillation which is showed in every response of beam's total deformation. Highest total deformation is achieved in slider support beam of 0.5 thicknesses, 1.08 mm in 1.12 second. First ripple seen in responses is at 0.84 second. Meanwhile, response of knife-edge and fixed support beam show a similarity. The ripple in this situation is caused by beat modulation from the front and rear tire.

Improvement of ride performance with an active suspension based on fuzzy logic control

The physiological and psychological effect of vehicle vibrations on passengers is still a challenging problem. Therefore, the passenger ride comfort, which depends on a combination of vehicle displacement (heave) and angular displacement (pitch), has been one of the major issues of vehicle design. This paper proposes a fuzzy logic control (FLC) strategy for active vehicle suspension system which is utilized to generate counter-force to isolate vibration from the rough ground. A four degree-of-freedom (DOF) half car mathematical model is firstly presented. And a “decoupling transformation” is applied to the translation and pitch motion. The hydraulic actuator is then introduced as well. Last the ADMAS control module is used to render co-simulation between ADAMS and MATLAB to verify efficiency of FLC and decoupling transformation. Compared with passive suspension system, it is indicated that the proposed active suspension system is very effective in reducing peak values of vehicle body accelerations, especially within the most sensitive frequency range of human response. The root mean square of vehicle vertical and pitch angle accelerations is reduced. Therefore, the ride comfort is improved.

Simulation analysis of the EUSAMA Plus suspension testing method including the impact of the vehicle untested side

The work deals with the simulation analysis of the half car vehicle model parameters on the suspension testing results. The Matlab simulation software was used. The considered model parameters are involved with the shock absorber damping coefficient, the tire radial stiffness, the car width and the rocker arm length. The consistent vibrations of both test plates were considered. Both wheels of the car were subjected to identical vibration, with frequency changed similar to the EUSAMA Plus principle. The shock absorber damping coefficient (for several values of the car width and rocker arm length) was changed on one and both sides of the vehicle. The obtained results are essential for the new suspension testing algorithm (basing on the EUSAMA Plus principle), which will be the aim of the further author's work.

Optimization and static output-feedback control for half-car active suspensions with constrained information

In this paper, the static output-feedback control problem of active suspension systems with information structure constraints is investigated. In order to simultaneously improve the ride comfort and stability, a half car model is used. Other constraints such as suspension deflection, actuator saturation, and controller constrained information are also considered. A novel static output-feedback design method based on the variable substitution is employed in the controller design. A single-step linear matrix inequality (LMI) optimization problem is solved to derive the initial feasible solution with a sparsity constraint. The initial infeasibility issue of the static output-feedback is resolved by using state-feedback information. Specifically, an optimization algorithm is proposed to search for less conservative results based on the feasible controller gain matrix. Finally, the validity of the designed controller for different road profiles is illustrated through numerical examples. The simulation results indicate that the optimized static output-feedback controller can achieve better suspension performances when compared with the feasible static output-feedback controller.

Accumulated tolerance analysis of suspension by geometric tolerances based on multibody elasto-kinematic analysis

Tolerance design of vehicle suspension is an important factor that affects the ride and handling quality and cost of the vehicle. Also, applying geometric tolerance to an analysis model is found to be a difficult process. This paper presents a method for tolerance analysis of wheel alignment of vehicle suspension. Monte-Carlo simulation method is applied to multibody elasto-kinematic model to analyze the accumulated geometric tolerances. As an example, Macpherson Strut Type front half car model is used, and wheel alignment dispersion and contribution ratio to the dispersion by accumulated geometric tolerances is computed. This paper also presents an efficient modeling and analysis method for elasto-kinematic model of vehicle suspensions by computing the stiffness matrix analytically. The simulation results of a Macpherson Strut Type demonstrates the validity and accuracy of the proposed method.

Coupling Mechanism and Decoupled Suspension Control Model of a Half Car

A structure decoupling control strategy of half-car suspension is proposed to fully decouple the system into independent front and rear quarter-car suspensions in this paper. The coupling mechanism of half-car suspension is firstly revealed and formulated with coupled damping force (CDF) in a linear function. Moreover, a novel dual dampers-based controllable quarter-car suspension structure is proposed to realize the independent control of pitch and vertical motions of the half car, in which a newly added controllable damper is suggested to be installed between the lower control arm and connection rod in conventional quarter-car suspension structure. The suggested damper constantly regulates the half-car pitch motion posture in a smooth and steady operation condition meantime achieving the expected completely structure decoupled control of the half-car suspension, by compensating the evolved CDF.

Experimental validation and robustness analysis of a multiple model switching antilock braking system control algorithm

In this paper, antilock braking system (ABS) control algorithms based on multiple model switching lead lag controllers are designed and are experimentally validated. Algorithms are designed to be adaptive with changing driving and road conditions in a switched multiple model manner. The effectiveness of the switching controllers is evaluated during transitions between different road friction coefficients. As the structure of the original experimental test device did not allow for the dynamic modification of the friction coefficient, controller switching stability was demonstrated under varying normal wheel load conditions implemented through simple modifications made on the test setup. The performance of the proposed controllers against varying vehicle speed and friction was also evaluated through simulations involving a half car braking model where a combined multiple model controller and observer structure was implemented. Experimental and simulation results indicate that the proposed control method is a potential candidate for implementation on a test vehicle.

Multi-Objective Optimization of Vehicle Passive Suspension System Using NSGA-II, SPEA2 and PESA-II

This paper presents a constrained multi-objective optimization study of vehicle passive suspension system which is modeled as a passive half car ride model. For multi-objective optimization the most widely used multi-objective evolutionary algorithms such as NSGA-II, SPEA2 and PESA-II are employed. The potential of the MOEAs in obtaining the better Pareto front of optimal solutions and in maintaining the diversity among the optimal solutions is tested by conducting 2 and 3-objective optimization studies. The results show that NSGA-II is able to yield a better Pareto front in terms of minimizing the objective vector but SPEA2 and PESA-II has a better diversified set of optimal solutions. Overall, all three algorithms have performed equally in optimizing the problem with the nature of the equations is second order ordinary differential equations.