Optimal Preview Semiactive Suspension

1996 ◽  
Vol 118 (1) ◽  
pp. 99-105 ◽  
Author(s):  
L. Jezequel ◽  
V. Roberti

This paper examines an optimal preview semiactive suspension of a quarter-coach model moving along randomly profiled track. This optimal computer-controlled suspension is designed only to dissipate energy, and is able to use knowledge of track irregularities over a distance L in front of the train. Thus the deformation of the track can be taken into account when calculating the semi-active suspension control law. First, the expression of the optimal preview semiactive control law is established. Then, using a two-degrees-of-freedom quarter-coach model, preview information is shown to improve the behavior of an optimal non-preview semi-active system, which can come close to the performance of an active system.

Author(s):  
Sorin MARCU ◽  
◽  
Dinel POPA ◽  
Nicolae-Doru STANESCU ◽  
Nicolae PANDREA

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.


1986 ◽  
Vol 108 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Aleksander Hac´

A discrete-continuous vibrating system, which can be treated as a model of a vehicle with an active suspension moving on a randomly profiled road, is considered in this paper. By the use of stochastic optimal control and estimation theory the suspension control forces and the steady-state behavior of an optimally controlled system in the presence of measurement errors are calculated and compared with the performance of an optimal passive system. The emphasis is on modeling and measurement problems. The need for taking body elasticity into account in the vehicle model is considered and the influence of sensor arrangement and accuracy upon the performance of the active system is determined.


Author(s):  
D A Crolla ◽  
D N L Horton ◽  
R H Pitcher ◽  
J A Lines

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.


Author(s):  
S. Gosselin-Brisson ◽  
M. Bouazara ◽  
M. J. Richard

This paper presents the design of an active suspension controller for an automotive vehicle. A four degrees of freedom linear model is used to represent a vehicle with different front and rear characteristics. Filtered road and acceleration inputs are applied to the model to simulate real life use. The performance criterion are filtered to include frequency sensitivity and weighted based on a standard passive suspension system. Independent front and rear controllers are optimised with the genetic algorithm. The controller includes linear gains and frequency dependency to take advantage of these two different control methods. The number of sensors and the order of the filters are limited to facilitate implementation on a real vehicle.


2010 ◽  
Vol 2010 ◽  
pp. 1-19 ◽  
Author(s):  
Lingjiang Chai ◽  
Tao Sun

A full vehicle model with seven degrees of freedom based on active suspension control is established, and linear quadratic gaussian (LQG) is designed by applying optimal control theory. Especially, the methodology of Analytic Hierarchy Process (AHP) is used to make the selection of weighted coefficients of performance indexes, which can reduce ineffective job in contrast with experience method. From the simulation results, it is shown that ride quality of the vehicle with active suspension has been effectively improved in comparison with the vehicle of passive suspension by the methodology of AHP applying to the selection of the weights.


2015 ◽  
pp. 992-1039
Author(s):  
Laiq Khan ◽  
Shahid Qamar

Suspension system of a vehicle is used to minimize the effect of different road disturbances for ride comfort and improvement of vehicle control. A passive suspension system responds only to the deflection of the strut. The main objective of this work is to design an efficient active suspension control for a full car model with 8-Degrees Of Freedom (DOF) using adaptive soft-computing technique. So, in this study, an Adaptive Neuro-Fuzzy based Sliding Mode Control (ANFSMC) strategy is used for full car active suspension control to improve the ride comfort and vehicle stability. The detailed mathematical model of ANFSMC has been developed and successfully applied to a full car model. The robustness of the presented ANFSMC has been proved on the basis of different performance indices. The analysis of MATLAB/SMULINK based simulation results reveals that the proposed ANFSMC has better ride comfort and vehicle handling as compared to Adaptive PID (APID), Adaptive Mamdani Fuzzy Logic (AMFL), passive, and semi-active suspension systems. The performance of the active suspension has been optimized in terms of displacement of seat, heave, pitch, and roll.


Author(s):  
R. Michael Van Auken

The control of wheeled ground vehicle suspension systems is well suited for analysis and refinement using multi-input multi-output (MIMO) control law synthesis methods for linear systems. Usually it is necessary and desirable to develop the control algorithms using a reduced order model of the system. Since such vehicles are also characterized by correlated road inputs with time delay between the front and rear wheels, it is also desirable to consider this delay during the model reduction process. If this delay is taken into consideration, then it may be possible to develop low order control algorithms which compensate for the vehicle modes that are disturbed by the road inputs, resulting in improved overall performance. This paper describes the application of model reduction to a model of a ground vehicle for active suspension control law synthesis. The vehicle is described by a high order MIMO model of a “half-car” with four rigid-body degrees of freedom and flexible body modes to account for structural vibration, plus additional states to represent colored noise road disturbance inputs. Fourth order MIMO models suitable for control law synthesis are then determined using internal balancing, taking into consideration the time delay between the front and rear wheels, followed by subsystem elimination. The performance of the vehicle (high order model) with the resulting low order active suspension control laws is then assessed.


2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Daniel Soto-Guerrero ◽  
José Gabriel Ramírez-Torres

This document introduces the holonomic flying capabilities of the Hexapodopter, a six-legged walking machine capable of vertical take-off and landing. For ground locomotion, each limb has two degrees-of-freedom (2DoF); while the thrust required for flying is provided by six motors mounted close to every knee, so the thrust vector can be reoriented depending on the configuration of each limb. The capacity of reorienting the thrust forces makes the Hexapodopter a true holonomic vehicle, capable of individually controlling its six degrees-of-freedom (6DoF) on the air without reorienting any of the thrust motors nor the body. The main design criteria and validation will be discussed on this paper, as well as a control law for the vehicle.


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