Suspension Damping Research Articles

Experimental analysis of 2 DOF quarter-car passive and hydraulic active suspension systems for ride comfort

This paper describes an experimental analysis of 2 degree-of-freedom (DOF) quarter-car passive suspension system and hydraulic active suspension system (QC-H-ASS) for ride comfort. The passive suspension system, which models a quarter-car suspension, consists of the sprung mass, unsprung mass, a suspension spring and damper and a tyre spring. A hydraulic actuator has been considered as one of the most viable choices for an active suspension system due to its high power-to-weight ratio and low cost. Thus this model is modified to a 2 DOF QC-H-ASS by placing a hydraulic actuator, with its attendant control instrumentation, in between sprung and unsprung masses. The results show considerable improvement in ride comfort over the conventional passive system. The details of the quarter-car model development with the test set-ups for the passive and hydraulic active suspension systems, suspension elements employed, experimental analysis and results are presented.

Sensitivity Analysis of the Elastic Properties of Rail Vehicle Suspensions on Vibration Based on the HXN5 Locomotive Model

The dynamic performance of suspensions plays direct role in vibration control of railway vehicles and also has great impact on the ride comfort and operation stability. For assessment of the influence, a method of sensitivity analysis was performed, in which a Multi-Body System (MBS) dynamic model for the HXN5 locomotive counting for significant DOFs and nonlinearities was developed in SIMPACK platform and validated by real tests. More than tens of dynamic simulations were performed by a variety of damping and stiffness coefficients of the primary and secondary suspensions. By simulation, it is found that the vertical stiffness and damping of the primary suspension have the most sensitive influence. The lateral stiffness of the primary suspension, the longitudinal and lateral stiffness as well as the longitudinal and vertical damper of the secondary suspension possess the least effect on the railway locomotive vibration characteristics. It is also shown parameters of the longitudinal stiffness of the primary suspension, the vertical stiffness and lateral damper of secondary suspensions are of intermediate influence.

Design Principle and Method of a Passive Hybrid Damping Suspension System

This work presents an approach to realize hybrid damping passively on the basis of inerter-spring-damper system, and demonstrates a passive hybrid damping suspension system that offers the performances of skyhook and groundhook dampers, but without the need of an inertial frame. The design principle and method of the system are presented, and a full-car model is built to analyze and compare the performances of the conventional passive, ideal and passive hybrid damping suspensions. The results demonstrate that the ideal and passive hybrid damping suspensions have the quite consistent performance that they both can suppress body and wheel resonances. As a result, the presented suspension improves ride comfort and safety significantly. It therefore has a good comprehensive performance.

An experimental comparison between semi–active and passive suspensions for air–cushion vehicles

An experimental heave made model of a tracked air–cushion vehicle incorporating on–off semi–active (SA) damper suspension is described. Preliminary tests are conducted to assess the SA pneumatic damper characteristics. For identical sinusoidal ground inputs, the totally passive and on–off SA damping schemes are compared in terms of sprung mass vibration isolation properties. It is shown that the semi–active suspension offers significant advantages over the corresponding passive suspensions, while at the same time requiring only a small amount of control energy. Although the performance of the pneumatic SA device is judged to be adequate for the case under investigation, it is concluded that, for more demanding applications, requiring higher controller speeds of response, an hydraulic SA implementation will probably have to be used.

Nonlinear ride analysis of heavy vehicle using local equivalent linearization technique

A multi–degree–of–freedom ride model of a typical tractor–semitrailer configuration comprising of nonlinear suspension damping mechanisms is developed. A local equivalent linearisation technique based on energy balance is employed to obtain the ride response of the nonlinear vehicle model. The critical behaviour of vehicle suspension(s) lock–up due to high magnitude of Coulomb (dry) friction is modelled and incorporated in the analytical technique such that the nonlinear behaviour of the system can be effectively simulated by the equivalent linear system. The effectiveness of local equivalent linearisation technique is demonstrated by comparing it with respect to conventional numerical integration and statistical linearisation techniques. A comprehensive parametric study is performed to investigate the influence of vehicle suspension characteristics, vehicle geometry, speed, highway profile and trailer loading patterns.

Simulation and Analysis of Ride Comfort of 4WD Electric Vehicle

Taking the independent four motorized wheels driving electric vehicle (4WD EV) as study object, the method and index evaluating ride comfort of automobile suspension system were described, and the input model of random road excitation and the dynamics model of 1/4 vehicle vibration system were established, then the simulation of ride comfort of the established model was conducted, so the evaluating indexes’ responses in time domain and frequency domain were obtained. Above all, the changes of these indexes which are suspension damping, spring stiffness and un-sprung mass were analyzed, their effects on the ride comfort of electric vehicle driven by motorized wheel studied, thus provided reference for the development of electric vehicle driven by in-wheel motor.

Optimization of Suspension Under the Condition of Curved Track in Railway Vehicle

This paper presents the optimization of suspension characteristics under the condition of curved track railway vehicles. Reducing lateral acceleration on curved track is an issue for high-speed railway vehicles. In terms of curved track running environments, reducing the lateral vibration of railway vehicles is critical to safety and curving performance. The properties of lateral damping and stiffness of both primary and secondary suspension show effect on wheel-set, bogie and car-body. Analysis for reducing the lateral vibration of rail vehicles with respect to the characteristics of both primary and secondary suspension has been developed using ADAMS/Rail. Response Surface Method has been chosen for the purpose of verifying correlation effects among design parameters. Also, this paper suggests the method for designing optimal suspension of railway vehicles on curved track. The optimization result indicates decrement of lateral acceleration on wheel-set by 3% and bogie by 1% on curved track. Finally, this paper comes to the conclusion that suspension system of railway vehicle (KTX I) is properly designed when regarding lateral vibration of railway vehicle on diverse curved track condition.

Coordinate Control of Vehicle Semi-Active Suspension Based on Adams/Car and Matlab/Simulink

To improve the ride comfort performance of electrical vehicle (EV) with in-wheel motor, the paper established a multi-body dynamic model of the vehicle, two road models and the suspension coordinate controller.The suspension coordinate, which can adjust suspension damper in real-time, was designed for the semi-active air suspension based fuzzy PID to control the suspension force, then the co-simulation were carried out under different conditions based on Adams and Matlab/Simulink. The results showed that the control method enhanced the ride comfort performance of EV with in-wheel motor significantly, especially the pitch performance.

Control of the motorized active suspension damper for good ride quality

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.

Response of a half-car model with optimal magnetorheological damper parameters

In this paper, control of the stationary response of a half-car model with a magnetorheological (MR) damper moving over a random road is considered. The MR damper is characterized using Bingham and modified Bouc–Wen models whose parameters are determined optimally using a multi-objective optimization technique and nondominated sorting genetic algorithm II. The multi-objective optimization problem is solved by minimizing the difference between the root mean square sprung mass acceleration, the sum of the front and rear suspension strokes and the sum of the front and rear road holding response of the half-car model with the MR damper, and those of an active suspension system based on linear quadratic regulator (LQR) control. The control force of the MR damper suspension is constrained to lie within ±5% of the control force corresponding to the active suspension system based on LQR control. It is observed that the MR damper suspension systems with optimal parameters perform an order of magnitude better than the passive suspension and perform as well as active suspensions with limited state feedback, and closer to the performance of fully active suspensions. In the case of MR damper suspensions, the vehicle response statistics are obtained using the equivalent linearization method and verified by Monte Carlo simulation.

A model of human walking energetics with an elastically-suspended load

Elastically-suspended loads have been shown to reduce the peak forces acting on the body while walking with a load when the suspension stiffness and damping are minimized. However, it is not well understood how elastically-suspended loads can affect the energetic cost of walking. Prior work shows that elastically suspending a load can yield either an increase or decrease in the energetic cost of human walking, depending primarily on the suspension stiffness, load, and walking speed. It would be useful to have a simple explanation that reconciles apparent differences in existing data. The objective of this paper is to help explain different energetic outcomes found with experimental load suspension backpacks and to systematically investigate the effect of load suspension parameters on the energetic cost of human walking. A simple two-degree-of-freedom model is used to approximate the energetic cost of human walking with a suspended load. The energetic predictions of the model are consistent with existing experimental data and show how the suspension parameters, load mass, and walking speed can affect the energetic cost of walking. In general, the energetic cost of walking with a load is decreased compared to that of a stiffly-attached load when the natural frequency of a load suspension is tuned significantly below the resonant walking frequency. The model also shows that a compliant load suspension is more effective in reducing the energetic cost of walking with low suspension damping, high load mass, and fast walking speed. This simple model could improve our understanding of how elastic load-carrying devices affect the energetic cost of walking with a load.

Improving Vehicle Lateral Stability Based on Variable Stiffness and Damping Suspension System via MR Damper

The capability of a variable stiffness and damping (VSVD) suspension system via a magnetorheological (MR) damper on improving vehicle lateral stability is investigated in this paper. First, a type of the VSVD suspension system is briefly introduced with the application of variable damping to realize the capability of VSVD. Then, variable damping via the MR damper is extended, and the characteristics of damping force are presented with the Bouc-Wen model. Then, the proposed VSVD system is inserted into a full vehicle model as a front suspension system to control tire normal forces. A control strategy composed of a fuzzy controller that the output is wheel slip ratio and a simple on/off controller to model the application of VSVD is developed to illustrate its ability in improving vehicle stability. It is shown from simulation that VSVD can increase tire normal forces and make vehicles present better performance on lateral stability.

1B13 Experimental investigation on a controllable colloidal damper for vehicle suspension(The 12th International Conference on Motion and Vibration Control)

1B13 Experimental investigation on a controllable colloidal damper for vehicle suspension(The 12th International Conference on Motion and Vibration Control)

10.5937/jaes12-5445 = A contribution to passive shock absorber force investigation

Shock absorbers are fundamental part of the vehicle suspension. Suspensions are needed to guarantee vehicle handling and passenger riding comfort. For good handling and braking performance of the vehicle, the tire-road contact forces need to be as stable as possible. Each wheel should always remain in contact with the ground. Comfort means that vibrations, induced by road profile during riding, are of a minimal nuisance to the passengers. When designing a new vehicle, a lot of development effort is focused on the optimal choice of the suspension parameters, stiffness and damping. This paper presents some results of an experimental study conducted on three shock absorbers types that are in current production at Magneti-Marelli. Experimental tests were performed in conditions of random excitation. The aim of this study, based on the experimental data and by use of statistical methods, was to investigate which of the kinematic parameters of excitation has the major impact on damping force of shock absorber (displacement, velocity or acceleration).

Driver Steering Control and Full Vehicle Dynamics Study Based on a Nonlinear Three-Directional Coupled Heavy-Duty Vehicle Model

Under complicated driving situations, such as cornering brake, lane change, or barrier avoidance, the vertical, lateral, and longitudinal dynamics of a vehicle are coupled and interacted obviously. This work aims to propose the suitable vehicle and driver models for researching full vehicle dynamics in complicated conditions. A nonlinear three-directional coupled lumped parameters (TCLP) model of a heavy-duty vehicle considering the nonlinearity of suspension damping and tire stiffness is built firstly. Then a modified preview driver model with nonlinear time delay is proposed and connected to the TCLP model to form a driver-vehicle closed-loop system. The presented driver-vehicle closed-loop system is evaluated during a double-lane change and compared with test data, traditional handling stability vehicle model, linear full vehicle model, and other driver models. The results show that the new driver model has better lane keeping performances than the other two driver models. In addition, the effects of driver model parameters on lane keeping performances, handling stability, ride comfort, and roll stability are discussed. The models and results of this paper are useful to enhance understanding the effects of driver behaviour on full vehicle dynamics.

The Effect of Vibration and Vehicle Body Movement of Car Suspension Systems due to Different Damper Characteristics in Cornering Tests

This paper investigates the effect of vibration and vehicle body movements acting on the vehicles wheel due to the different damping characteristics of suspension systems. Three different damping characteristics damper named Absorber A, Absorber B and Absorber C was installed on the suspension system of the Proton Persona which was used as a test car. This test car was equipped with accelerometers and wire potentiometer sensor on the front and rear suspensions, gyroscopic, Global Positioning System (GPS) and connect with DEWEsoft software as a data acquisition. To study the effect of three different damper characteristics on suspension system, the ride comfort analysis and car body movement analysis were used to analyze the result during experimental testing. There were 3 maneuver testing experiment were performed including steady-state cornering, single-lane change and slalom testing experiment. Based on the results, comparison between the suspension damper characteristics due to the driving maneuvers and car movement were made and their performance also were ranked. Absorber A was the hardest damper as compared to Absorber C and Absorber B according to the damping constant value. The result showed that the best performance for car movement made by Absorber A then followed by Absorber C and Absorber B, while the best performance for ride comfort analysis was made by Absorber B followed by Absorber C and A.

Improving the critical speeds of high-speed trains using magnetorheological technology

With the rapid development of high-speed railways, vibration control for maintaining stability, passenger comfort, and safety has become an important area of research. In order to investigate the mechanism of train vibration, the critical speeds of various DOFs with respect to suspension stiffness and damping are first calculated and analyzed based on its dynamic equations. Then, the sensitivity of the critical speed is studied by analyzing the influence of different suspension parameters. On the basis of these analyses, a conclusion is drawn that secondary lateral damping is the most sensitive suspension damper. Subsequently, the secondary lateral dampers are replaced with magnetorheological fluid (MRF) dampers. Finally, a high-speed train model with MRF dampers is simulated by a combined ADAMS and MATLAB simulation and tested in a roller rig test platform to investigate the mechanism of how the MRF damper affects the train’s stability and critical speed. The results show that the semi-active suspension installed with MRF dampers substantially improves the stability and critical speed of the train.

The Method for Identification of Damping Coefficient of the Trucks Suspension

The modern commercial vehicle with a weight of more than 3,5 [Mg] is a complex design solution, which contains many of mechatronic systems. The standard equipment are the ability of the driver assistance systems such as ABS (Anti-Lock Braking System), ESP (Electronic Stability Program), ASR (Acceleration Slip Regulation). The technical condition of the modern car's suspension determines the value of the indicators of road safety. An essential element of the suspension system, whose function is to change the mechanical vibration energy into thermal energy, is the shock absorber. Incorrect functioning of shock absorbers affects the quality of the operation of these systems improve safety. In the case of gradually wears of shock absorber even an experienced driver is able to notice this phenomenon. For this reason it becomes necessary the need for regular technical condition monitoring of dampers. Diagnostic dampers on buses and trucks are limited to the organoleptic examination and propose based on intermediate symptoms such as accelerated tire wear. The paper describes the method for estimating the suspension damping characteristics of commercial vehicle in operating conditions.

Development of an adaptive relay control law for damped suspension of multi-wheeled vehicles in order to prevent linear-angular fluctuations in the housing

Development of an adaptive relay control law for damped suspension of multi-wheeled vehicles in order to prevent linear-angular fluctuations in the housing

Research on Vibration Model of Special Vehicle Based on Dual-Mass System

Taking a special vehicle vibration system as the research object, according to the actual structure of the chassis, the spring damping and stiffness of the nonlinear characteristics and the tire vertical elastic accounted, a nonlinear vibration model of special vehicle based on dual-mass-system is set up. The tire radial stiffness value is analyzed in Ansys, a simulation is performed by leading the mathematical model of suspension system into Adams, a characteristic curve of stiffness and damping of suspension system is obtained.