A Novel Active Suspension System for Automotive Application

1994 ◽  
Vol 208 (4) ◽  
pp. 243-250 ◽  
Author(s):  
N J Leighton ◽  
J Pullen
Keyword(s):  
Computer Simulation ◽  
Active Suspension ◽  
Input Power ◽  
Suspension System ◽  
Automotive Application ◽  
Test Results ◽  
Active System ◽  
Spring Element

This paper describes a novel type of active suspension based on a buckling spring element installed in an actively controlled variable leverage system. The development of the suspension system through stages of computer simulation, implementation and test is outlined, together with the test results. The suspension system does not fall into any of the established categories of active system but may be seen as fitting into a recently identified category of variably leverage systems. The system is shown to be capable of controlling a vehicle body's motion while providing excellent road input isolation and requiring input power levels of below 150 watts per wheel.

A Study of Control Strategy for Vehicle Semi-Active Suspension System

1991 ◽  
Author(s):  
Yiming Zhang ◽  
Ye Lin
Keyword(s):  
Optimal Control ◽  
Control Strategy ◽  
Active Suspension ◽  
Suspension System ◽  
Statistical Characteristics ◽  
Active System ◽  
Optimal Control Strategy ◽  
Performance Limit ◽  
Passive Suspension ◽  
Isolation Performance

Abstract This paper investigates a reference control strategy for Vehicle semi-active suspension. The control is conducted by following the idea optimal active controller. The passive actuator is set to optimal whenever the active and passive actuators have the same signs; and set to zero output whenever the two signs are opposite. The simulation results of a 2DoF vehicle show that the semi -active suspension system can follow the ideal active system very well, both are superior to conventional passive systems. In this paper, a 2DoF vehicle model was also used to study a statistical optimal control strategy of the semi-active suspension system. The statistical optimal concept is the result of the combination of the nonlinear programming and controllable damper. A way of estimating statistical characteristics of road irregularities was also proposed. Vehicle active, suspension, due to its perfect v i bra t i on isolation performance, gets moreand more attention. Active suspension can be generally divided into two categories, totally active suspension system and semi-active suspension system. From the published results it is known that active suspension can surpass the performance limit of conventional passive suspension and greatly improve the vehicle riding comfort and steering ability. But active suspension has a critical disadvantage of less applicability, due to its high cost and low reliability. Also it consumes large amount of energy as it works. The idea of semi-active suspension was put forward to overcome the shortcoming of active suspension. It is a compromise between active suspension and passive suspension. Semi-active suspension has approximately the same behavior as active suspension, and almost consumes no energy as it works. So semi-active suspension possesses a great potential in application. At. present, in the field of suspension research over the world, a great deal of attention is paied to semi-active suspension. At present, for the cotrol of semi-active suspension the widely studied strategy is “on off” control [1] [2], which is first put forward by Karnopp. “On-off” control can eliminate the phenomenon of vibration amplification for passive suspension, thus it can improve the suspension performance to certain extent. At present, no substantive result has been obtained yet in the field of optimal control of semi-active suspension. This paper will investigate a reference control strategy on the basis of linear optimal control. The control is conducted by following the optimal ctive controller. The referrence control result is optimal when the outputs of the active and semi-active force generators have the same signs.

Mathematical Model of a Buckled Spring for Vehicle Active Suspension

1997 ◽  
Author(s):  
Shiping Yao ◽  
Colin Morgan ◽  
Nigel J. Leighton
Keyword(s):  
Dynamic Performance ◽  
Active Suspension ◽  
Effective Rate ◽  
Suspension System ◽  
Leaf Spring ◽  
Practical Application ◽  
Resonance Effects ◽  
Spring Element ◽  
Constant Rate ◽  
Force Displacement

Abstract The basic characteristic of a conventional spring is that of a constant rate, that is a linear force-displacement relationship. If, however, a flat, thin leaf spring is end-loaded past its buckling point it will deform into a curve and the resulting force-displacement relationship can be made virtually flat; that is a very low effective rate is seen, once the buckling force is exceeded. A novel form of automotive active suspension system proposed by Leighton & Pullen (1994) relies upon the “buckled spring” element acting through a variable geometry wishbone assembly to provide wheel to body forces that are controllable by a low power actuator but are virtually independent of wheel to body displacement. The dynamic behavior of the spring element is also significant, since resonance effects may affect the vibration isolating properties of the suspension system and may result in unstable modes of motion. This paper presents a rigorous derivation of the static and dynamic characteristic of the spring element and of the effect of design compromises that are essential for practical application. Comparison of the experimental and simulation results shows that the simulation can be used to predict the static and dynamic performance of the spring.

Zero-Energy Active Suspension System for Automobiles With Adaptive Sky-Hook Damping

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Kalpesh Singal ◽  
Rajesh Rajamani
Keyword(s):  
Active Suspension ◽  
Suspension System ◽  
Energy Management System ◽  
Zero Energy ◽  
Passive System ◽  
Active System ◽  
Active Suspensions ◽  
Resonant Frequencies ◽  
Active Systems ◽  
Automotive Suspension

Previous research has shown that a semiactive automotive suspension system can provide significant benefits compared to a passive suspension but cannot quite match the performance of a fully active system. The advantage of the semiactive system over an active system is that it consumes almost zero energy by utilizing a variable damper whose damping coefficient is changed in real time, while a fully active suspension consumes significant power for its operation. This paper explores a new zero-energy active suspension system that combines the advantages of semiactive and active suspensions by providing the performance of the active system at zero energy cost. Unlike a semiactive system in which the energy is always dissipated, the proposed system harvests and recycles energy to achieve active operation. An electrical motor-generator is used as the zero-energy actuator and a controller and energy management system are developed. An energy adaptive sky-hook gain is proposed to prevent the system from running out of energy, thereby eliminating the need to switch between passive and active systems. The results show that the system performs at least as well as a passive system for all frequencies, and is equivalent to an active system for a broad range of frequencies including both resonant frequencies.

scholarly journals Design of the optimal control for the active suspension

2021 ◽  
Vol 31 ◽  
pp. 1-6
Author(s):  
Sorin MARCU ◽  
◽  
Dinel POPA ◽  
Nicolae-Doru STANESCU ◽  
Nicolae PANDREA
Keyword(s):  
Optimal Control ◽  
Degrees Of Freedom ◽  
Active Suspension ◽  
Suspension System ◽  
Vertical Acceleration ◽  
Passive System ◽  
Active System ◽  
Matlab Simulink ◽  
Two Degrees Of Freedom ◽  
Lqr Control

The main purpose of the suspension is to minimize vertical acceleration. Through this paper we aim to analyze two PID and LQR control techniquesto reduce system vibrations. The active system will be compared to a passive system using two types of profile. Matlab / Simulink software is used to evaluate the performance of the two controllers using a system with two degrees of freedom. The analysis shows that we can control the suspension system using the two techniques to improve the comfort and safety of the vehicle.

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.

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.

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.

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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