Hardware-in-the-loop Testing of On-Off Controllers in Semi-Active Suspension Systems

International audienceThis paper presents an experimental validation of a proposed Frequency Estimation-Based (FEB) controller for semi-active suspensions by using a Hardware-in-the-Loop (HiL) platform of a Quarter of Vehicle (QoV) model. The FEB approach is compared with three commercial On-Off controllers that have shown good results in comfort and road holding: Sky-Hook (SH), Groud-Hook (GH) and Mix-1-sensor (M1S). The comparison was done under the same experimental tests; the standards ISO-2631 and BS-6841 are used to evaluate the comfort and the Root Mean Square (RMS) index to quantify the road holding. The QoV model belongs to a front-left corner of a pick-up truck; the used experimental Magneto-Rheological (MR) damper is not symmetric and only hast 2 manipulation states. Experimental results show that the FEB controller has the best comfort performance at low frequencies (outperforms the benchmark controllers at 11.2%); while, for road holding, the improvement is slight; however, FEB controller works better for both goals simultaneously. By analyzing the suspension deflection, the FEB controller reduces up to 32.8% of motion respect to the GH controller. Additionally, the manipulation of the SH and GH controllers have several changes of actuation that do not allow the stabilization of the force in its desirable value; while FEB controller has a soft actuation defined on bandwidths

A LPV Quarter of Car with Semi-active Suspension Model including Dynamic Input Saturation

International audienceThis paper formulates a Linear Parameter Varying (LPV ) model for a semi-active quarter of car (QoC). The formulation depends on a new MR damper model which is based on the measurement of the maximum deflection velocity. In this device, the saturation is dynamic and it depends on the maximum current to apply and the velocity deflection. One scheduling parameter includes the variation of the damping coefficient and the dynamic saturation of the MR damper decreasing the conservatism of the model. Open and closed loop frequency responses comparison of the proposed model and a nonlinear QoC are given. The results shows that the new structure for the model is feasible and the nonlinear saturation can be used to weight the controller's output. In both tests, the applied current always is kept realistic

Adaptive Semi-Active Suspension Design Using Gain-Scheduling

International audienceA novel approach to design a road adaptive semi-active suspension is proposed. Two scheduling parameters are considered: the road frequency and the type of road. A single corner vehicle model with a nonlinear dynamic model of the semi-active damper is considered. The suspension deflection and its derivative are used as feedback signals. Nonlinear simulations show that an adaptive suspension controller: Frequency-Estimation-Based with road Adaptation (FEBA) provides better comfort and road holding over different types of road. The improvement of the performance ranges from 5-10 %

Control Strategies for an Automotive Suspension with a MR Damper

6 pagesInternational audienceA semi-active control system of an automotive suspension with an Magneto-Rheological (MR) damper as a key element is considered. Given its hysteretical and nonlinear behavior, the inclusion of a MR damper model in a controller synthesis is presented. Two controllers are proposed from different approaches: LPV control and a Frequency Estimation-Based (FEB) control. The LPV controller uses a LPV model of a quarter of vehicle based on the MR damper dynamics. The FEB controller is a model-free controller. These controllers are compared under comfort oriented standards. Simulation results show these controllers as new alternatives with excellent response for comfort and road holding (improving the comfort between 10-20 %)

A Semi-active Control-oriented Damper Model for an Automotive Suspension

International audienceThis paper deals with the modelling of a magneto-rheological damper as a component of a quarter-car model. The objective is to provide an analysis of the transient and frequency behavior of the suspension system in order to evaluate the inherent linearities of two identified models: a complex one and a control-oriented one. The models have a common structure but the effect of the current and the dynamic behavior has different principle. The results show that the design of experiments is a key issue in the identification process. A quarter of a vehicle which includes a control-oriented damper model is identified as well-suited for the synthesis of controllers that perform well in terms of accurate frequency response when compared with that of a quarter-car with a semi-active suspension simulated with experimental data

Hysteresis Modelling for a MR Damper

International audienceAn experimental dataset of a commercial Magneto-Rheological (MR) damper is exploited for identification of a Hysteresis-based Control-Oriented model. The model wellness for hysteresis, saturation and transient responses is shown through validation with experimental data. A study case that includes a Quarter of Vehicle (QoV) shows that the hysteresis phenomena could affect the primary ride and vehicle handling. Several analysis based on open and closed loop simulation demonstrated that hysteresis must be considered for controller design

Optimization of weighting function selection for H∞ control of semi-active suspensions

International audienceThe intent of this article is to present a methodology that deals with steering/braking coordination task, for automotive vehicle yaw control scheme. Because of the tire nonlinearity that is mainly due to the saturation of cornering forces, vehicle handling performance is improved but limited to a certain extent only by steering control. Direct yaw moment control using braking forces is effective not only in the linear region but also in the nonlinear ranges of the tire friction circle. However, braking effect is not desirable in normal driving situations. Consequently, the maximum benefit is gained through the coordinated and combined use of both steering and braking control methods. In this study, the coordination task is achieved through a suitable gain scheduled LPV (Linear Parameter Varying) controller, where braking control is activated only when the vehicle reaches the handling limits. The controller is synthetized within the LMI framework, while ensuring linear optimal Hinf performances. Computer simulations, carried out on a complex full vehicle model subject to critical driving situations, show that the vehicle handling is much improved by the integrated control system compared against an uncontrolled vehicle

Modélisation et commande LPV d'un amortisseur magnéto-rhéologique

International audienceCet article concerne l'étude d'un amortisseur semiactif de type Magnéto-Rhéologique. Tout d'abord un modèle de type quart-de-véhicule est représenté comme un système Linéaire à Paramètres Variants, afin de prendre en compte le comportement non linéaire de l'amortisseur. Ce modèle est validé à partir de données expérimentales obtenues au Tecnologico de Monterrey (Mexique) dans le cadre d'un projet PCP Mexique-France. Dans un second temps, une commande de type H2/LPV est synthétisée pour le modèle LPV quart-de-véhicule obtenu afin d'améliorer la tenue de route tout en préservant un bon confort pour les passagers. Des résultats de simulation montrent l'intérêt de la méthode proposée en comparaison avec d'autres types d'approches

Fault Detection in Automotive Semi-active Suspension : Experimental Results

http://papers.sae.org/2013-01-1234/International audienceA proposal of Fault detection using Linear Parameter Varying (LPV) systems is experimentally validated on embedded systems. The fault detection system is oriented to faulty sensors and / or actuators. The study case is a Quarter of Vehicle (QOV) with suspension using a controllable shock absorber which uses a SkyHook controller. The experimental testbed uses Hardware-in-the-Loop (HiL) to validate the fault detection approach. The HiL is an automotive Electronic Control Unit (ECU), and the QOV model is embedded in a Field-Programmable Gate Array (FPGA). Results exhibit the effectiveness of the approach which is consistent with numerical simulation. These results open the application of LPV approaches to commercial vehicles since it is easy of implementation for several features such as, low computation load, lumped parameter model and available for nonlinear dynamic systems