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.

Influence of the road profile accuracy on disturbance compensation in active suspension systems

2021 ◽  
Vol 69 (6) ◽  
pp. 485-498
Author(s):  
Felix Anhalt ◽  
Boris Lohmann
Keyword(s):  
Ride Comfort ◽  
Feedforward Control ◽  
Active Suspension ◽  
Disturbance Compensation ◽  
Critical Factors ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Road Profile ◽  
Profile Accuracy

Abstract By applying disturbance feedforward control in active suspension systems, knowledge of the road profile can be used to increase ride comfort and safety. As the assumed road profile will never match the real one perfectly, we examine the performance of different disturbance compensators under various deteriorations of the assumed road profile using both synthetic and measured profiles and two quarter vehicle models of different complexity. While a generally valid statement on the maximum tolerable deterioration cannot be made, we identify particularly critical factors and derive recommendations for practical use.

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.

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.

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.

scholarly journals Hybrid Modelling and Sliding Mode Control of Semi-Active Suspension Systems for Both Ride Comfort and Road-Holding

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1286
Author(s):  
Ayman Aljarbouh ◽  
Muhammad Fayaz
Keyword(s):  
Hybrid Model ◽  
Ride Comfort ◽  
Sliding Mode ◽  
Active Suspension ◽  
Suspension System ◽  
Vehicle Suspension ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
System Components ◽  
And Control

Rigorous model-based design and control for intelligent vehicle suspension systems play an important role in providing better driving characteristics such as passenger comfort and road-holding capability. This paper investigates a new technique for modelling, simulation and control of semi-active suspension systems supporting both ride comfort and road-holding driving characteristics and implements the technique in accordance with the functional mock-up interface standard FMI 2.0. Firstly, we provide a control-oriented hybrid model of a quarter car semi-active suspension system. The resulting quarter car hybrid model is used to develop a sliding mode controller that supports both ride comfort and road-holding capability. Both the hybrid model and controller are then implemented conforming to the functional mock-up interface standard FMI 2.0. The aim of the FMI-based implementation is to serve as a portable test bench for control applications of vehicle suspension systems. It fully supports the exchange of the suspension system components as functional mock-up units (FMUs) among different modelling and simulation platforms, which allows re-usability and facilitates the interoperation and integration of the suspension system components with embedded software components. The concepts are validated with simulation results throughout the paper.

Research on Optimal Control and Simulation for Active Suspension Systems

2013 ◽  
Vol 340 ◽  
pp. 631-635
Author(s):  
Yong Fa Qin ◽  
Jie Hua ◽  
Long Wei Geng
Keyword(s):  
Optimal Control ◽  
Ride Comfort ◽  
Mathematic Model ◽  
Active Suspension ◽  
Suspension System ◽  
Vehicle Body ◽  
Vertical Acceleration ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems

Vehicles with active suspension systems become more ride comfort and maneuverable stability, many types of active suspensions have been applied to passenger vehicles, but one of the shortcomings of an active susupension system is that the additional control power consumption is needed. The core issues of designing an active suspension system are to minimiaze vibration magnitute and control energy comsuption of the active suspension system. A new mathematic model for an active suspension system is established based on vehicle dynamics and modern control theory. An optimal control law is constructed through solving the Riccati equation, and then the transfer function is deduced to describe the relationship between the vetical velosity of the road roughness and the output of suspension system. Three typical parameters of vehicle ride comfort are researched, such as vertical acceleration of vehicle body, dynamic deflection of suspension system and dynamic deformation of tires. A case of a quarter vehicle model is studied by simulation to show that the proposed method of modeling and designing optimal controller are suitable to develop active suspension systems.

scholarly journals Enhanced Sliding Mode Control for a Nonlinear Active Suspension Full Car Model

2021 ◽  
Vol 1 (4) ◽  
pp. 501-522
Author(s):  
Erliana Samsuria ◽  
Yahaya M. Sam ◽  
Fazilah Hassan
Keyword(s):  
Sliding Mode Control ◽  
Ride Comfort ◽  
Controller Design ◽  
Sliding Mode ◽  
Active Suspension ◽  
Pso Algorithm ◽  
Hydraulic Actuator ◽  
The Road ◽  
Car Model ◽  
Mode Control

This paper delivers findings on optimal robust control studies of nonlinear full car models. A nonlinear active suspension full car model is used, which considers the dynamic of a hydraulic actuator. The investigation on the benefit of using Sliding Mode Control (SMC) structure for the effective trade-off between road handling. The design of SMC in the chassis/internal subsystem is enhanced by modifying a sliding surface based on Proportional-Integral-Derivatives (PID) with the utilization of particle swarm optimization (PSO) algorithm in obtaining the best optimum value of control parameters. The switching control is designed through the Lyapunov function, which includes the boundedness of uncertainties in sprung masses that can guarantee the stability of the control design. The responses of the proposed controller have improved the disturbance rejection up to 60% as compared to the conventional SMC controller design and shown the high robustness to resist the effect of varying the parameter with minimal output deviations. The study proved that the proposed SMC scheme offers an overall effective performance in full car active suspension control to perform a better ride comfort as well as the road handling ability while maintaining a restriction of suspension travel. An intensive computer simulation (MATLAB Simulink) has been carried out to evaluate the effectiveness of the proposed control algorithm under various road surface conditions.

Multi-Object Control of Active Suspension Subject to Parameter Uncertainties under Non-Stationary Running

2012 ◽  
Vol 224 ◽  
pp. 440-443
Author(s):  
Li Ping Zhang ◽  
Li Xin Guo
Keyword(s):  
Ride Comfort ◽  
Active Suspension ◽  
State Feedback Control ◽  
Parameter Uncertainties ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Hard Constraints ◽  
Feedback Control Strategy ◽  
Control Forces ◽  
And Control

Based on the building of non-stationary road surface excitation mode, a study on the active suspension control under non-stationary running condition was conducted using control, state feedback control strategy for linear systems with time-domain hard constraints was propose. The proposed approach was applied to design active suspension systems on the basis of a two-degree-of-freedom quarter car mode, Simulation results show that the proposed constrained controller can achieve a promising improvement on ride comfort, while keeping dynamic suspension deflections, dynamic tire loads and control forces within given bounds, even non-stationary running.

Application of Constrained H∞ Control to Active Suspension Systems on Half-Car Models

2004 ◽  
Vol 127 (3) ◽  
pp. 345-354 ◽  
Author(s):  
H. Chen ◽  
Z. -Y. Liu ◽  
P. -Y. Sun
Keyword(s):  
Ride Comfort ◽  
Active Suspension ◽  
Disturbance Attenuation ◽  
Linear Matrix ◽  
Actuator Dynamics ◽  
Lmi Optimization ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Hard Constraints ◽  
And Control

This paper formulates the active suspension control problem as disturbance attenuation problem with output and control constraints. The H∞ performance is used to measure ride comfort such that more general road disturbances can be considered, while time-domain hard constraints are captured using the concept of reachable sets and state-space ellipsoids. Hence, conflicting requirements are specified separately and handled in a nature way. In the framework of Linear Matrix Inequality (LMI) optimization, constrained H∞ active suspensions are designed on half-car models with and without considering actuator dynamics. Analysis and simulation results show a promising improvement on ride comfort, while keeping suspension strokes and control inputs within bounds and ensuring a firm contact of wheels to road.

scholarly journals Hybrid Sliding Mode Control of Full-Car Semi-Active Suspension Systems

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2442
Author(s):  
Ayman Aljarbouh ◽  
Muhammad Fayaz ◽  
Muhammad Shuaib Qureshi ◽  
Younes Boujoudar
Keyword(s):  
Ride Comfort ◽  
Sliding Mode ◽  
Experimental Tests ◽  
Active Suspension ◽  
Suspension Systems ◽  
Production Code ◽  
Car Suspension ◽  
Automotive Production ◽  
Suspension Model ◽  
And Control

With the advance in technology in driving vehicles, there is currently more emphasis on developing advanced control systems for better road handling stability and ride comfort. However, one of the challenging problems in the design and implementation of intelligent suspension systems is that there is currently no solution supporting the export of generic suspension models and control components for integration into embedded Electronic Control Units (ECUs). This significantly limits the usage of embedded suspension components in automotive production code software as it requires very high efforts in implementation, manual testing, and fulfilling coding requirements. This paper introduces a new dynamic model of full-car suspension system with semi-active suspension behavior and provides a hybrid sliding mode approach for control of full-car suspension dynamics such that the road handling stability and ride comfort characteristics are ensured. The semi-active suspension model and the hybrid sliding mode controller are implemented as Functional Mock-Up Units (FMUs) conforming to the Functional Mock-Up Interface for embedded systems (eFMI) and are calibrated with a set experimental tests using a 1/5 Soben-car test bench. The methods and prototype implementation proposed in this paper allow both model and controller re-usability and provide a generic way of integrating models and control software into embedded ECUs.

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