Multi-objective control of decoupled vehicle suspension systems

IEEE Transactions on Control Systems Technology, 2002

Multiobjective optimal control strategy is pursued here for finding feedback control laws used in controlled suspensions for automotive vehicles. The balanced vehicle ride and handling performances are the main concern of this paper. The ride performance (car body performance) is characterized by an 2 system norm, and the handling performance (wheel performance) is characterized by an system norm, and the control method optimizes the mixed 2 performances. The 2 and system norms used in the mixed 2 performance optimization are scaled by the corresponding open-loop norms such that the relative importance of the individual variables can be reflected in the performance index for the vector variables. The comparison between passive and controllable suspensions shows in simulation the advantages of this optimal control strategy. The simulation result also shows that the invariant point for controlled suspensions in the quarter car case exists in the seven degree-of-freedom model. The control scheme was tested and validated for a test vehicle, current paper only shows the simulation work.

PROCEEDINGS OF THE 45TH INTERNATIONAL CONFERENCE ON APPLICATION OF MATHEMATICS IN ENGINEERING AND ECONOMICS (AMEE’19)

A look-ahead approach to mobile robot path tracking based on distance-only measurements A linear quadratic regulator synthesis for a semi-active vehicle suspension part 2 -Multiobjective synthesis Abstract. The paper considers obtaining of the control law, based on a Linear Quadratic Regulator (LQR), of a semiactive suspension of a vehicle represented in the vertical plane -so-called "Half car model". The basic circumstance for the suspension synthesis is the simultaneous realization of the requirements for the vehicle's ride comfort and its road holding as a factor for the vehicle's stability. The first requirement is related to the reduction of the acceleration transmitted to the sprung mass and driver, and as generally imposes one soft suspension. The second is related to the reduction of the dynamic component of the normal forces of interaction between the tires and road pavement and as generally, imposes a more hard suspension. Furthermore, those requirements are changing in some frequency diapasons of the excitations, arisen from the road unevenness. The possibilities of the passive implementation of the vehicle's suspension, for the obtaining of a sufficiently good compromise, are limited. The using of the semi-active controllable dampers gives considerably more possibilities in this direction. In this first part of the paper the dynamic model of the system is given and all characteristics, needed for control law synthesis, are obtained.

Journal of Computational and Nonlinear Dynamics, 2014

This article deals with the dynamic response optimization of mechanical systems, based on the computation of independent state sensitivities. Specifically, the dynamic behavior of a coach is analyzed in detail so as to improve its response in terms of handling and ride comfort behaviors. To that end, the coach is modeled as an 18-DOF multibody system, whose equations of motion are posed using an efficient dynamic formulation based on Maggi's equations. Next, a direct-automatic differentiation approach for the computation of independent state sensitivities is applied. This allows one to quantify the effect of 19 design parameters on the vehicle dynamic response and to compute the design sensitivities or objective function gradients. Finally, handling and ride comfort objective functions are defined and are used to carry out a multi-objective suspension design optimization process, improving the vehicle response by 70% in an effective yet automatic way.

Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2004

This paper studies a new FAMOS strategy for suspension control. FAMOS stands for frequency-adaptive multi-objective suspension. This strategy adjusts the control law based on certain frequency information and achieves a balanced ride and handling performance. It contains a road profile identifier, several multi-objective control laws which optimize a mixed H 2 /H ϱ performance index based on different performance preferences, and an adaptive law based on the frequency contents estimated from the identified road profile. The strategy is applied to a quarter car suspension control and the simulation results show that the achieved performance is better than many existing results.

2009

There are many types of car suspensions control. H1 control of vehicle suspension is studied in the literature for a brave time ago. We can define active suspensions as control systems incorporating a parallel spring and an electronically controlled damper. The contribution of this paper relies on H1 control design to improve comfort and road holding of the car, and on control validation through simulation on an quarter Car and Half Car model with seat-passengers of the suspensions system. In this paper an H1 controller is designed for a actuated active suspension system of a quarter-modelled and half-modelled with seat-passengers vehicle in a cascade feedback structure. In this paper we will make a comparison between application of quarter car and half car model. In the framework of Linear Matrix Inequality (LMI) optimization, constrained H1 active suspensions are designed on half-car models.

IOP Conference Series: Materials Science and Engineering

This article explores the task for the multicriterial synthesis of the control-law from the type Linear Quadratic Regulator (LQR), for a semi-active vehicle suspension. It is consists of obtaining the optimal compromise between the requirements for sufficient ride comfort and vehicle stability on the road pavement. The relevant object-functions are defined. It is proposed an algorithm for a multicriterial hierarchical approach for identifying in the Pareto's set of solutions, this solution that realizes the optimal compromise in the sense of John Nash's sustained strategy from the antagonistic games theory. Based on this approach, a new algorithm for the synthesis of LQR is proposed, combined with a compensator, in which the weight matrices being the subject of optimization. This synthesis was applied for a spatial model of a semi-active suspension of a vehicle. J J J J J J zt d t J z T T   min max J n game

Robust design and multi objective optimization of semi active suspension system, 2020

This paper presents a robust multi-objective optimal design (RMOP) of a passenger car with a semiactive suspension system. The mean-effective values of the root mean square of the passenger's head acceleration, suspension travel, and tire deflection are considered as design objectives. The passive components of the suspension and the design details of the Linear Quadratic Regulator (LQR) algorithm are used as design parameters. During the design, global sensitivity analysis is carried out using the Fourier Amplitude Sensitivity Test (FAST) to specify the elements of the model that can highly alter the design objectives. The mass of the passenger's head and upper body, the mass of the passenger's lower body and cushion, passenger and cushion's elastic properties, and the sprung mass of the vehicle are selected for the sensitivity analysis. Results show that the design criteria are very sensitive to the variations in the sprung mass of the vehicle as compared to the other parameters. As a result, the variations in this parameter and passive elements of the suspension system are considered. Constraints are applied on the objectives in compliance with the requirements of ISO 2631-1 on the design of car suspension systems. The optimization problem is solved by the NSGA-II (non-dominated sorting genetic algorithm II) and robust Pareto front and set are obtained. The Pareto set includes multiple design options from which the decision-maker can choose to implement. Responses of the passenger's head acceleration, suspension travel, and tire deflection show that the robust multi-objective design algorithm (RMOA) is very effective and guarantees less sensitivity to the suspension passive elements.

Journal of Vibration and Control, 2004

We present an application of a new controller order reduction technique with stability and performance preservation based on linear matrix inequality optimization to an active suspension system. In this technique, the rank of the residue matrix of a proper rational approximation of a high-order Hoo controller subject to the H,,norm of a frequency-weighted error between the approximated controller and high-order H,, controller is minimized. However, since solving this matrix rank minimization problem is very difficult, the rank objective function is replaced with the nuclear-nonn that can be reduced to a semidefinite program, so that it can be solved efficiently Application to the active suspension system of the Automatic Laboratory of Grenoble provides a fourth-order controller. The experimental results show the control specifications are met to a large extent.

Article , 2025

Developing a reliable control algorithm for a mechatronic suspension can be tricky because of the nonlinear nature of the system and the necessity to achieve a good trade-off between the requirements of road handling ability and the comfort of passengers. This paper assesses the performance of two control methods, the H-Infinity (H ∞) and linear quadratic regulator (LQR), applied to an active suspension system. This suspension system uses sensors and actuators in addition to the springs and dampers of the traditional suspension system. It combines software, electrical, and mechanical parts to improve the car handling and convenience of passengers on the road. A quarterly car automotive suspension model consisting of 2 degrees of freedom (2 DOF) is proposed as the case study. The suspension deviation, wheel displacement, and upward acceleration of the car frame are the performance parameters considered in this research. The aim is to strike a perfect balance while achieving minimum readings of car chassis acceleration and wheel deflection demonstrated by each controller when steady state error approaches zero from the suspension response. The body acceleration and wheel deflection affect the passenger comfort and road handling, respectively. Time-based simulation is carried out in MATLAB/Simulink environment to verify the effectiveness of the proposed control mechanisms. The results of the simulation demonstrate the effectiveness and robustness of the proposed control schemes.

2020

To improve road dealing with and passenger consolation of a vehicle, a suspension system is supplied. An<br>active suspension system is taken into consideration better than the passive suspension system. In this<br>paper, an active suspension system of a linear quarter vehicle is designed, that's issue to exclusive<br>disturbances on the road. Since the parametric uncertainty within the spring, the shock absorber and the<br>actuator has been taken into consideration, robust control is used. H∞ and µ-Synthesis controllers of are<br>used to improve using consolation and road dealing with potential of the vehicle, in addition to confirm the<br>sturdy stability and overall performance of the system. In the H∞ design, we designed a driving force for<br>passenger consolation and to preserve the deflection of the suspension small and to reduce the disturbance<br>of the road to the deflection of the suspension. For the µ synthesis system, ...