Dynamic Behaviour of a 7 DoF Passenger Car Model

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
P.P.D. Rao ◽  
S. Palli ◽  
R.C. Sharma
Keyword(s):  
Natural Frequencies ◽  
Ride Comfort ◽  
Active Suspension ◽  
High Energy ◽  
Suspension System ◽  
Mode Shapes ◽  
Active System ◽  
Passenger Car ◽  
Conventional Vehicle ◽  
Suspension Systems

Conventional vehicle suspension systems, which are passive in nature consists of springs with constant stiffness and dampers with constant damping coefficient. These suspension systems cannot meet the characteristics such as ride comfort, road handing and suspension deflection during abnormal road conditions simultaneously. Active and semi-active suspension systems are the solutions to achieve the desired suspension characteristics. Since, active system is bulky and requires high energy for working, a semi-active suspension system is considered in the present work to analyze vehicle traversing over various road profiles for ride comfort. Mathematical model of a 7 DoF passenger car is formulated using Newton’s method. A semi-active suspension system with skyhook linear control strategy avoids the road excitations at resonant frequencies by shifting the natural frequencies of the model by varying damping coefficients based on the vehicle response for different road conditions where the excitations could be harmonic, transient and random. Modal analysis is carried out to identify the un-damped natural frequencies and mode shapes for different values of damping. The above analyses are carried out through analytical and numerical methods using MATLAB and ANSYS software respectively and the results obtained from both are in good agreement.

Control Bifurcations in a Nonlinear Active Suspension System for System Design

2005 ◽  
Author(s):  
Amit Shukla ◽  
Jeong Hoi Koo
Keyword(s):  
Control System ◽  
Ride Comfort ◽  
Active Suspension ◽  
Nonlinear Damping ◽  
Suspension System ◽  
Suspension Systems ◽  
System A ◽  
Controlled Systems ◽  
Automotive Suspension ◽  
Magneto Rheological

Nonlinear active suspension systems are very popular in the automotive applications. They include nonlinear stiffness and nonlinear damping elements. One of the types of damping element is a magneto-rheological fluid based damper which is receiving increased attention in the applications to the automotive suspension systems. Latest trends in suspension systems also include electronically controlled systems which provide advanced system performance and integration with various processes to improve vehicle ride comfort, handling and stability. A control bifurcation of a nonlinear system typically occurs when its linear approximation loses stabilizability. These control bifurcations are different from the classical bifurcation where qualitative stability of the equilibrium point changes. Any nonlinear control system can also exhibit control bifurcations. In this paper, control bifurcations of the nonlinear active suspension system, modeled as a two degree of freedom system, are analyzed. It is shown that the system looses stability via Hopf bifurcation. Parametric control bifurcation analysis is conducted and results presented to highlight the significance of the design of control system for nonlinear active suspension system. A framework for the design of feedback using the parametric analysis for the control bifurcations is proposed and illustrated for the nonlinear active suspension system.

Parametric Study on Proportional Integral Derivative Controlled Semi-Active Suspension System

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
E.M Allam ◽  
M.A.A Emam ◽  
Eid.S Mohamed
Keyword(s):  
Active Suspension ◽  
Suspension System ◽  
Proportional Integral Derivative ◽  
Active System ◽  
Proportional Integral ◽  
Quarter Car Model ◽  
Suspension Systems ◽  
Working Space ◽  
Active Suspension Systems ◽  
Quarter Car

This paper presents the effect of the suspension working space, body displacement, body acceleration and wheel displacement for the non-controlled suspension system (passive system) and the controlled suspension system of a quarter car model (semi-active system), and comparison between them. The quarter car passive and semi-active suspension systems are modelled using Simulink. Proportional Integral Derivative controllers are incorporated in the design scheme of semi-active models. In the experimental work, the influence of switchable damper in a suspension system is compared with the passive and semi-active suspension systems.

Active Suspension Control for an Off-Road Vehicle

1987 ◽  
Vol 201 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D A Crolla ◽  
D N L Horton ◽  
R H Pitcher ◽  
J A Lines
Keyword(s):  
Attitude Control ◽  
Ride Comfort ◽  
Active Suspension ◽  
Active System ◽  
Road Vehicle ◽  
Suspension Systems ◽  
Body Attitude ◽  
Active Suspension Systems ◽  
Suspension Control ◽  
Recent Developments

After a review of recent developments in active suspension systems, a semi-active system fitted to an off-road vehicle is described. Theoretically predicted results are presented alongside data measured on the actual vehicle. The benefits of the semi-active system over a passive suspension are improved ride comfort and improved body attitude control.

Study of Dynamic Performance of a Vehicle With Planar Suspension Systems in a Split-µ Braking-in-Turning

2010 ◽  
Author(s):  
Jian Jun Zhu ◽  
Amir Khajepour ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Transient Response ◽  
Ride Comfort ◽  
Dynamic Performance ◽  
Suspension System ◽  
Dynamic Behaviors ◽  
Conventional Vehicle ◽  
Suspension Systems ◽  
Simulation Results ◽  
Different Characteristics ◽  
Better Than

A planar suspension system (PSS) has spring-damping struts in both the vertical and longitudinal directions so that the vibrations and shocks caused by road obstacles in any direction within the wheel plane can be effectively absorbed. Consequently, the ride comfort of a PSS vehicle can be improved considerably compared to a conventional vehicle. For a vehicle with such suspension systems, however, the wheels can move forth and back with respect to the chassis. The dynamic behaviors of a PSS vehicle under some special conditions, such as a split-μ turning combined with braking operation, may exhibit different characteristics. This paper presents the study of the transient response of a vehicle with PSS in such a case. The simulation results are also compared with those of a similar vehicle with conventional suspension under the same operational condition. The study demonstrates that the handling behavior of a PSS vehicle is generally comparable with, and in some conditions, even better than that of a conventional vehicle.

Effect of Non-Linear Components on the Performance of a Hydro -Pneumatic Slow-Active Suspension System

1996 ◽  
Vol 210 (1) ◽  
pp. 23-34 ◽  
Author(s):  
S M El-Demerdash ◽  
D A Crolla
Keyword(s):  
Linear Model ◽  
Linear Models ◽  
Ride Comfort ◽  
Active Suspension ◽  
Front Wheel ◽  
Suspension System ◽  
Approximation Technique ◽  
Active System ◽  
Working Space ◽  
Non Linear

In this work, the effects of component non-linearities on the ride performance of a hydro-pneumatic slow-active suspension system are studied theoretically. Based on the quarter car linear model, linear optimal control theory is used to calculate the feedback and feedforward gains. These gains are used in both linear and non-linear models with and without preview control. The Pade approximation technique is used to represent the preview time resulting from a preview sensor mounted on the vehicle front bumper to measure the road irregularities ahead of the front wheel. The results on a typical major road showed that at similar r.m.s. values of suspension working space, the non-linear slow-active system with preview provided a 28 per cent improvement in ride comfort and a 17 per cent reduction in dynamic tyre load compared with a passive system. However, the inclusion of non-linear effects of the components increases the ride comfort acceleration by 10 per cent and suspension working space by 12 per cent compared to the equivalent linear model at approximately equal values of r.m.s. dynamic tyre load.

An experimental and theoretical investigation into the design of an active suspension system for a racing car

1997 ◽  
Vol 211 (3) ◽  
pp. 161-173 ◽  
Author(s):  
D. J. Purdy ◽  
D. N. Bulman
Keyword(s):  
Active Suspension ◽  
Open Loop ◽  
Suspension System ◽  
Active System ◽  
Ride Height ◽  
Active Suspensions ◽  
Suspension Systems ◽  
System A ◽  
Active Suspension Systems ◽  
The Difference

The well-established quarter car representation is used to investigate the design of an active suspension system for a racing car. The work presented is from both a practical and theoretical study. The experimental open-loop and passive responses of the suspension system are used to validate the model and estimate the level of damping within the system. A cascade control structure is used, consisting of an inner body acceleration loop and an outer ride height loop. Comparisons are made between the experimental results and those predicted by the theory. During the 1980s and early 1990s a number of Formula 1 teams developed active suspension systems to improve the performance of cars. Little detail was published about these systems because of the highly competitive nature of the application. Some of these systems were very sophisticated and successful. Because of this, speed increased considerably and because of the costs involved, the difference in performance between the lower and higher funded teams became unacceptable. For this reason, the governing body of motor sport decided to ban active suspensions from the end of the 1993 racing season. Both authors of this paper were involved with different racing teams at that time, and this paper is an introduction to the very basic philosophy behind a typical active system that was employed on a Formula 1 car.

Optimal Design of Active and Semi-Active Suspensions Including Time Delays and Preview

1993 ◽  
Vol 115 (4) ◽  
pp. 498-508 ◽  
Author(s):  
A. Hac´ ◽  
I. Youn
Keyword(s):  
Ride Comfort ◽  
Controller Design ◽  
Piecewise Linear ◽  
Active Suspension ◽  
Front Wheel ◽  
Active System ◽  
Control Laws ◽  
The Road ◽  
Suspension Systems ◽  
And Control

Several control laws for active and semi-active suspension based on a linear half car model are derived and investigated. The strategies proposed take full advantage of the fact that the road input to the rear wheels is a delayed version of that to the front wheels, which in turn can be obtained either from the measurements of the front wheels and body motions or by direct preview of road irregularities if preview sensors are available. The suspension systems are optimized with respect to ride comfort, road holding and suspension rattle space as expressed by the mean-square-values of body acceleration (including effects of heave and pitch), tire deflections and front and rear suspension travels. The optimal control laws that minimize the given performance index and include passivity constraints in the semi-active case are derived using calculus of variation. The optimal semi-active suspension becomes piecewise linear, varying between passive and fully active system and combinations of them. The performances of active and semi-active systems with and without preview were evaluated by numerical simulation in the time and frequency domains. The results show that incorporation of time delay between the front and rear axles in controller design improves the dynamic behavior of the rear axle and control of body pitch motion, while additional preview improves front wheel dynamics and body heave.

H∞ Control of Active Suspension System for a Quarter Car Model

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
N.M. Ghazaly ◽  
A.S Ahmed ◽  
A.S Ali ◽  
G.T Abd El- Jaber
Keyword(s):  
Ride Comfort ◽  
Active Suspension ◽  
Suspension System ◽  
Passive Suspension ◽  
Quarter Car Model ◽  
Suspension Systems ◽  
Car Model ◽  
Active Suspension Systems ◽  
Passive Suspension System ◽  
Quarter Car

In recent years, the use of active control mechanisms in active suspension systems has attracted considerable attention. The main objective of this research is to develop a mathematical model of an active suspension system that is subjected to excitation from different road profiles and control it using H∞ technique for a quarter car model to improve the ride comfort and road handling. Comparison between passive and active suspension systems is performed using step, sinusoidal and random road profiles. The performance of the H∞ controller is compared with the passive suspension system. It is found that the car body acceleration, suspension deflection and tyre deflection using active suspension system with H∞ technique is better than the passive suspension system.

Simulation and Analysis of a Fractionally Controlled Active Suspension System Using Quarter Car Model

2015 ◽  
Author(s):  
Duval A. Johnson
Keyword(s):  
Fractional Calculus ◽  
Body Position ◽  
Active Suspension ◽  
Suspension System ◽  
Control Force ◽  
Active System ◽  
Suspension Systems ◽  
Car Suspension ◽  
Automobile Suspension ◽  
Quarter Car

This study is conducted to provide preliminary data that fractional calculus can be used to optimize active automobile suspension systems. Most automobile suspension systems perform their duties using a single spring with fixed damping rates and are referred to as being a passive system. An active suspension system has the ability to directly control force actuators in the suspension system or by varying the damping rates within the shock absorbers to provide control over body position, velocity, and acceleration. A mathematical model for a quarter car suspension system has been obtained to compare passive, integer, and fractionally controlled active suspension systems and show that fractional calculus may be used to improve the performance of any active system.

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