Stochastic Optimal Control of Vehicles With Elastic Body and Active Suspension

1986 ◽  
Vol 108 (2) ◽  
pp. 106-110 ◽  
Author(s):  
Aleksander Hac´
Keyword(s):  
Optimal Control ◽  
Stochastic Optimal Control ◽  
Measurement Errors ◽  
Active Suspension ◽  
Active System ◽  
State Behavior ◽  
Controlled System ◽  
Sensor Arrangement ◽  
Suspension Control ◽  
Control Forces

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.

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.

scholarly journals Reducing Response Time in Fork-Join Systems under Heavy Traffic Via Imbalance Control

2013 ◽  
Vol 45 (4) ◽  
pp. 1137-1156
Author(s):  
Saul C. Leite ◽  
Marcelo D. Fragoso
Keyword(s):  
Optimal Control ◽  
Response Time ◽  
Control Problem ◽  
Stochastic Optimal Control ◽  
Numerical Experiments ◽  
Heavy Traffic ◽  
Controlled System ◽  
Reflected Diffusion ◽  
Stochastic Optimal Control Problem ◽  
Workload Imbalance

We consider the problem of reducing the response time of fork-join systems by maintaining the workload balanced among the processing stations. The general problem of modeling and finding an optimal policy that reduces imbalance is quite difficult. In order to circumvent this difficulty, the heavy traffic approach is taken, and the system dynamics are approximated by a reflected diffusion process. This way, the problem of finding an optimal balancing policy that reduces workload imbalance is set as a stochastic optimal control problem, for which numerical methods are available. Some numerical experiments are presented, where the control problem is solved numerically and applied to a simulation. The results indicate that the response time of the controlled system is reduced significantly using the devised control.

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.

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.

scholarly journals Reducing Response Time in Fork-Join Systems under Heavy Traffic Via Imbalance Control

2013 ◽  
Vol 45 (04) ◽  
pp. 1137-1156
Author(s):  
Saul C. Leite ◽  
Marcelo D. Fragoso
Keyword(s):  
Optimal Control ◽  
Response Time ◽  
Control Problem ◽  
Stochastic Optimal Control ◽  
Numerical Experiments ◽  
Heavy Traffic ◽  
Controlled System ◽  
Reflected Diffusion ◽  
Stochastic Optimal Control Problem ◽  
Workload Imbalance

We consider the problem of reducing the response time of fork-join systems by maintaining the workload balanced among the processing stations. The general problem of modeling and finding an optimal policy that reduces imbalance is quite difficult. In order to circumvent this difficulty, the heavy traffic approach is taken, and the system dynamics are approximated by a reflected diffusion process. This way, the problem of finding an optimal balancing policy that reduces workload imbalance is set as a stochastic optimal control problem, for which numerical methods are available. Some numerical experiments are presented, where the control problem is solved numerically and applied to a simulation. The results indicate that the response time of the controlled system is reduced significantly using the devised control.

Optimal Preview Semiactive Suspension

1996 ◽  
Vol 118 (1) ◽  
pp. 99-105 ◽  
Author(s):  
L. Jezequel ◽  
V. Roberti
Keyword(s):  
Degrees Of Freedom ◽  
Active Suspension ◽  
Control Law ◽  
Semiactive Control ◽  
Active System ◽  
Two Degrees Of Freedom ◽  
Suspension Control ◽  
Computer Controlled ◽  
Track Irregularities ◽  
Semiactive Suspension

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.

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