A suspension system with a variable roll centre for the improvement of vehicle handling characteristics

2001 ◽  
Vol 215 (6) ◽  
pp. 677-696 ◽  
Author(s):  
U Lee ◽  
C Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Body Side ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the improvement of vehicle handling characteristics using variable roll centre suspension (VRCS) is investigated. A vehicle with VRCS can improve stability and ride comfort by automatically controlling suspension geometry in accordance with the running conditions of the vehicle. To achieve this, a variable roll centre concept in the McPherson strut suspension system is suggested, while the two parts most sensitive for controlling the roll centre are suggested. One is between the vehicle body-side connecting portion of the lower arm and the vehicle body (control input, LCZ), and the other is between the vehicle body-side connecting portion of the strut and the vehicle body (control input, STY). Kinematic roll centre analysis, based on the analytic half-car model, shows that the use of two control inputs, LCZ and STY, can decrease migration of the roll centre and centre of gravity according to the side force. In order to quantify the relationship between roll centre and geometry control input and evaluate handling performance, a full vehicle model of 15 degrees of freedom (DOF) is constructed using multi-body dynamic analysis software, ADAMS. In step steering and double lane change manoeuvres, simulation results demonstrate that a vehicle with VRCS adjusts roll centre migration, and handling characteristics such as roll angle, lateral acceleration and yaw rate are much improved.

Enhancement of vehicle handling characteristics by suspension kinematic control

2001 ◽  
Vol 215 (2) ◽  
pp. 197-216 ◽  
Author(s):  
S H Lee ◽  
U K Lee ◽  
C S Han
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Lateral Acceleration ◽  
Vehicle Body ◽  
Control Input ◽  
Vehicle Handling ◽  
Kinematic Control ◽  
Front Suspension ◽  
Handling Characteristics ◽  
Suspension Geometry

In this paper, the enhancement of vehicle handling characteristics through the active kinematic control system (AKCS) is investigated. AKCS can improve the stability and ride comfort of a vehicle by automatically controlling suspension geometry in accordance with the running conditions of a vehicle. The variable roll centre suspension concept in a McPherson strut suspension is proposed, and lateral acceleration feedback control is derived to calculate the control input. The independent rear wheel steering system, which controls both rear wheels independently and actively, is also proposed. To achieve this, three suggested positions for controlling the suspension geometry are considered. The first position is between the mounting point of the lower arm of a McPherson front suspension and the vehicle body. The second position is between the mounting point of the strut and the vehicle body. The third position is between the mounting point of the lateral link of the multilink rear suspension and the vehicle body. In order to evaluate the handling performance, a 15 degrees of freedom full vehicle model is constructed using the commercial multibody analysis program ADAMS. The control inputs for integrated control of the front and rear suspensions are defined, and roll centre migration and vehicle behaviour are investigated. In step steering and double lane change manoeuvres, the simulation results demonstrate that integrated kinematic control can adjust the roll centre migration, by which the handling characteristics of the AKCS vehicle such as roll angle, lateral acceleration and yaw rate are much improved.

Golden Section Search Based Optimization of Road Vehicle Suspension System

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Prasad Bali ◽  
C.V. Chandrashekara
Keyword(s):  
Ride Comfort ◽  
Golden Section ◽  
Optimization Technique ◽  
Relative Displacement ◽  
Suspension System ◽  
Vehicle Body ◽  
Vehicle Handling ◽  
Golden Section Search ◽  
Design Requirements ◽  
Quarter Car

Suspension system is an important part of a vehicle which connects the road wheels and vehicle body. The major function of suspension is to isolate vehicle body from road disturbances. The design of suspension system is generally a compromise between many design requirements that aim to provide a comfortable ride and good vehicle handling. An optimization technique is used to choose the suspension parameters that meet these design requirements. In this present work a two degree of freedom quarter car vehicle vibration model is considered for optimization. Sprung mass acceleration and relative displacement of quarter car are considered as the measure of ride comfort and vehicle handling respectively. Golden section search optimization technique is used for single objective optimization of quarter car considering sprung mass acceleration as objective function and relative displacement as constraint. It is noticed that the accuracy level in getting the optimized value using this approach is comparatively high and reliable..

Use of nonlinear asymmetrical shock absorbers in multi-objective optimization of the suspension system in a variety of road excitations

2016 ◽  
Vol 231 (2) ◽  
pp. 372-387 ◽  
Author(s):  
Abolfazl Seifi ◽  
Reza Hassannejad ◽  
Mohammad Ali Hamed
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Low Cost ◽  
Suspension System ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Vehicle Handling ◽  
Multi Objective ◽  
Shock Absorbers ◽  
The Impact

In this study, a new method to improve ride comfort, vehicle handling, and workspace was presented in multi-objective optimization using nonlinear asymmetrical dampers. The main aim of this research was to provide suitable passive suspension based on more efficiency and the low cost of the mentioned dampers. Using the model with five degrees of freedom, suspension system parameters were optimized under sinusoidal road excitation. The main functions of the suspension system were chosen as objective functions. In order to better illustrate the impact of each objective functions on the suspension parameters, at first two-objective and finally five-objective were considered in the optimization problem. The obtained results indicated that the optimized viscous coefficients for five-objective optimization lead to 3.58% increase in ride comfort, 0.74% in vehicle handling ability, and 2.20% in workspace changes for the average of forward and rear suspension.

scholarly journals Mathematical Modelling of Two-Wheeler Suspension system in a wavy road

2019 ◽  
Vol 8 (11) ◽  
pp. 3630-3635
Keyword(s):  
Ride Comfort ◽  
Health Hazard ◽  
Suspension System ◽  
Vehicle Body ◽  
Continuous Exposure ◽  
Potential Health ◽  
Suspension Spring ◽  
The Road ◽  
Potential Health Hazard ◽  
Two Wheeler

Two wheelers like motorbikes and scooters are one of the major transports in India. In major cities and towns, it is most common private transport as it is fast and easy approach to the destination. But the prolonged drive in the two-wheeler leads to the potential health hazard and musco-skeletal disorder due to continuous exposure to the vibration caused during the ride and force transmitted to the vehicle body due to road irregularities. It is a challenge of automobile engineers to design a promising suspension system to overcome the risk of ride comfort during continuous driving. In this research, two-wheeler suspension system is modelled with a condition of bump and valley in a wavy road. The road surface is assumed to be wavy and the response of new suspension spring with different materials (stainless steel, tungsten and polymeric) along with viscous damper is analyzed and compared. By this analysis, it will be proposed to industry to modify the suspension system to improve its efficiency and reduce force transmitted to the human body to improve the ride comfort

Automobile active tilt based on active suspension with H∞ robust control

2020 ◽  
pp. 095440702096620
Author(s):  
Jialing Yao ◽  
Meng Wang ◽  
Yanan Bai
Keyword(s):  
Robust Control ◽  
Degrees Of Freedom ◽  
Load Transfer ◽  
Ride Comfort ◽  
Simulation Analysis ◽  
Active Suspension ◽  
Roll Angle ◽  
Lateral Acceleration ◽  
Roll Moment ◽  
Roll Control

Automobile roll control aims to reduce or achieve a zero roll angle. However, the ability of this roll control to improve the handling stability of vehicles when turning is limited. This study proposes a direct tilt control methodology for automobiles based on active suspension. This tilt control leans the vehicle’s body toward the turning direction and therefore allows the roll moment generated by gravity to reduce or even offset the roll moment generated by the centrifugal force. This phenomenon will greatly improve the roll stability of the vehicle, as well as the ride comfort. A six-degrees-of-freedom vehicle dynamics model is established, and the desired tilt angle is determined through dynamic analysis. In addition, an H∞ robust controller that coordinates different performance demands to achieve the control objectives is designed. The occupant’s perceived lateral acceleration and the lateral load transfer ratio are used to evaluate and explain the main advantages of the proposed active tilt control. To account the difference between the proposed and traditional roll controls, a simulation analysis is performed to compare the proposed tilt H∞ robust control, a traditional H∞ robust control for zero roll angle, and a passive suspension system. The analysis of the time and frequency domains shows that the proposed controller greatly improves the handling stability and anti-rollover ability of vehicles during steering and maintains acceptable ride comfort.

scholarly journals Sliding Mode Control of Laterally Interconnected Air Suspensions

2020 ◽  
Vol 10 (12) ◽  
pp. 4320 ◽  
Author(s):  
Dou Guowei ◽  
Yu Wenhao ◽  
Li Zhongxing ◽  
Amir Khajepour ◽  
Tan Senqi
Keyword(s):  
Ride Comfort ◽  
Control Method ◽  
Sliding Mode ◽  
Suspension System ◽  
Lateral Acceleration ◽  
Sliding Mode Controller ◽  
The Road ◽  
Air Suspension ◽  
Simulation Based ◽  
Different Levels

This paper presents a control method based the lateral interconnected air suspension system, in order to improve the road handling of vehicles. A seven-DOF (Degree of freedom) full-vehicle model has been developed, which considers the features of the interconnected air suspension system, for example, the modeling of the interconnected pipelines and valves by considering the throttling and hysteresis effects. On the basis of the well-developed model, a sliding mode controller has been designed, with a focus on constraining and minimizing the roll motion of the sprung mass caused by the road excitations or lateral acceleration of the vehicle. Moreover, reasonable road excitations have been generated for the simulation based on the coherence of right and left parts of the road. Afterwards, different simulations have been done by applying both bumpy and random road excitations with different levels of roughness and varying vehicle lateral accelerations. The simulation results indicate that the interconnected air suspension without control can improve the ride comfort, but worsen the road handling performance in many cases. However, by applying the proposed sliding mode controller, the road handling of the sprung mass can be improved by 20% to 85% compared with the interconnected or non-interconnected mode at a little cost of comfort.

Mechanism for the Reduction of Lateral Friction Capabilities of a Delaminated Tire

2012 ◽  
Author(s):  
Paul T. Semones ◽  
David A. Renfroe ◽  
H. Alex Roberts ◽  
Don Y. Lee
Keyword(s):  
Coefficient Of Friction ◽  
Test Procedure ◽  
Lateral Acceleration ◽  
Test Vehicle ◽  
Vehicle Handling ◽  
Passenger Vehicles ◽  
Handling Characteristics ◽  
Structural Rigidity ◽  
Vehicle Testing ◽  
Lateral Friction

Tire delamination is a significant vehicle dynamics safety problem contributing to the loss of control of passenger vehicles, often resulting in accidents and injuries. This paper examines vehicle handling characteristics after a complete outer tread belt separation on 2-steel belt and 3-steel belt tires. The test vehicle used to examine this phenomenon was a Ford 15-passenger van. The test procedure was the SAE J266 circle test, and the measure of effectiveness was taken to be the lateral acceleration at which the vehicle transitioned to an oversteer characteristic. For a typical tread separation on a 2-steel belted tire, the tire loses one of its steel belts and thus much of its structural rigidity. Vehicle testing using a 3-steel belted tire, in which only the outermost single belt was removed, and the remaining two belts were oriented along opposite diagonals, showed that the vehicle remained in an understeer condition at higher lateral accelerations than with the 2-steel belted tire, indicating that the retention of greater structural rigidity to the impaired tire resulted in it maintaining much of its cornering stiffness. Until now, it has been assumed that the reduction in cornering stiffness of a delaminated tire was predominately due to the low coefficient of friction of the exposed steel belt after delamination. The testing described in this paper suggests that a significant influence on the remaining cornering stiffness of the tire after tread separation is the overall remaining structural rigidity of the tire. From this testing, it is theorized that the rigidity of the delaminated tire is at least as important as the reduced coefficient of friction for the purposes of maintaining vehicle understeer behavior after a delamination.

Semi-active Fuzzy Sliding Mode Control of Full Vehicle and Suspensions

2005 ◽  
Vol 11 (8) ◽  
pp. 1025-1042 ◽  
Author(s):  
H. Liu ◽  
K. Nonami ◽  
T. Hagiwara
Keyword(s):  
Ride Comfort ◽  
Sliding Mode ◽  
Suspension System ◽  
Vehicle Body ◽  
Mode Switch ◽  
Low Frequencies ◽  
Comfort Care ◽  
Fuzzy Sliding Mode Control ◽  
Fuzzy Sliding Mode ◽  
Real Vehicle

The suspension of a vehicle is the support system between a vehicle body and wheels. The purpose of a suspension system is to support the vehicle body and increase ride comfort. Care must be taken in the design of a suspension system because if the attenuation force becomes large, the passenger will be subjected to a very rough ride under high-frequency disturbances, and if the attenuation force becomes small, the ride will feel overly soft at low frequencies. Furthermore, if the spring constant is too low, the vehicle’s natural frequency of vibration will be low, and thus the heave, rolling, and pitching will be large. In this study, a fuzzy sliding mode controller for a real vehicle has been designed. A new method for designing the fuzzy sliding mode switch hyperplane has been proposed. Experiment results are presented to confirm the effectiveness of this new algorithm.

An Approach on Performance Comparison of Quarter Car Suspension System

2014 ◽  
Vol 984-985 ◽  
pp. 629-633
Author(s):  
Palanisamy Sathishkumar ◽  
Jeyaraj Jancirani ◽  
John Dennie
Keyword(s):  
Degrees Of Freedom ◽  
Performance Comparison ◽  
Suspension System ◽  
Vehicle Body ◽  
Vehicle Suspension ◽  
Passive Suspension ◽  
Passenger Comfort ◽  
Car Model ◽  
Car Suspension ◽  
Vehicle Suspension System

The present article introduces an approach that combines passive and active elements to improve the ride and passenger comfort. The main aim of vehicle suspension system should isolate the vehicle body from road unevenness for maintaining ride and passenger comfort. The ride and passenger comfort is improved by reducing the car body acceleration caused by the irregular road surface. The vehicle body along with the wheel system is modelled as two degrees of freedom one fourth of car model. The model is tested on road bump with severe peak amplitude excitations. In the conclusion, a comparison of active, semi-active and passive suspension is shown using MATLAB simulations.

The Use of Accident Data in Studying Vehicle Handling Performance

1975 ◽  
Vol 189 (1) ◽  
pp. 243-258 ◽  
Author(s):  
I. S. Jones
Keyword(s):  
Weight Ratio ◽  
Control Measures ◽  
Lateral Acceleration ◽  
Loss Of Control ◽  
Accident Rate ◽  
Vehicle Handling ◽  
Handling Performance ◽  
Handling Characteristics ◽  
Accident Causation ◽  
Accident Data

A study to establish the relation between vehicle handling performance and accident causation. Since deficiencies in handling are likely to be associated with accidents involving loss of control, measures of handling which are likely to express proneness to loss of control are first suggested; emphasis is placed on simplicity of measurement to allow as many different models of car as possible to be included in the study. Accident rates for the various types of accident which are likely to be influenced by these parameters are then determined by model of car. The effect of other factors, such as variation in driver characteristics between different models of car on these rates is then assessed so that the relation between handling characteristics and accident frequency can be defined. Finally, the relative importance of the various measures of handling suggested are assessed. The results suggest that there is a definite relation between handling performance and accident causation although it is relatively small when compared to driver effects. In explaining the variation in the accident rate between different models of car, driver effects account for as much as 70 per cent; if driver effects are removed from the accident rate then handling parameters explain between 35 and 40 per cent of the remaining variation between models of car. The important parameters appear to be weight, a measure of the change in understeer as a function of lateral acceleration and power to weight ratio.

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