Motion planning control of the airpath of a S.I. engine with Valve Timing Actuators

International audienceWe address the control of the airpath of a turbocharged S.I. engine equipped with Variable Valve Timing actuators (VVT). Compared to standard configurations, the engine does not possess any external EGR (Exhaust Gas Recirculation) loop. Rather, VVT are used to produce internal EGR, providing similar beneficial effects in terms of emissions reduction. The airpath dynamics takes the form of a single mono-dimensional air balance in the intake manifold. In this equation, the VVT act as a disturbance by impacting on the air mass flow through the inlet valves. This impact can be estimated from real-time measurements. We use this information in a motion planning based control strategy by, successively, turning the driver's torque demand into a trajectory generation problem for the air mass contained in the intake manifold, and then deriving an intake manifold pressure trajectory. Supportive simulation results show the relevance of this approach and suggest ways of further improvements

Modeling and control of a Diesel HCCI engine

International audienceThis article focuses on the control of a Diesel engine airpath. We propose a detailed description of the airpath of a Diesel HCCI engine supported by experimental results. Moreover, we propose a simple, yet innovative, motion planning control strategy. At the light of this study, we can finally conclude, with supportive results, that motion planning is indeed an appropriate solution for controlling the airpath dynamics

Constrained motion planning for the airpath of a Diesel HCCI engine

International audienceA constrained motion planning control strategy is proposed for the airpath control of turbocharged Diesel engines using exhaust gas recirculation (EGR). The considered model uses simple balance equations. The fully actuated dynamics are easily inverted, yielding straightforward open-loop control laws. Yet, practical constraints need to be accounted for. Convergence is proven and stress that saturation of infeasible control values yields longer yet successful transients. This fact is supported by reported extensive experimental tests on a 4-cylinder engine in Homogeneous Charge Compression Ignition (HCCI) mode. Conclusions stress the possibility of taking into account the non- minimum phase effects of this system by a simple, yet efficient and realistic in practice, control law

Transient control of a Diesel engine airpath

International audienceThis article focuses on the control of a diesel engine airpath during transients. The proposed control methodology uses a motion planning technique combined with an observer and two inner loop controllers. We extend and improve our previously published results by providing proof of global convergence and stability. The EU cycle serves as benchmark, and detailed experimental results (including transients in HCCI mode) are presented

Estimation et contrôle dynamique longitudinale d un véhicule électrique avec moteurs-roue

L'objectif principal de cette thèse est l'étude de l'exploitation de systèmes moteurs-roues (machines électriques intégrées à la roue) pour le contrôle de la dynamique véhicule. Cette thèse est issue d'un co-financement (numéro 186-654, 2010-2013) entre le Laboratoire des Signaux et Systèmes (CNRS) et l'Institut Français du Pétrole et Énergies Nouvelles (IFPEN). Les avantages apportés par l'utilisation du moteur électrique sont avérés et de nouvelles techniques de contrôle sont développées pour optimiser son utilisation. Les lois de contrôle basent généralement sur la grandeur principale du moteur électrique: le couple transmis, qui peut être mesuré via le courant consommé. Une autre caractéristique importante du moteur électrique est son temps de réponse, avec le fait qu'il peut produire des couples négatifs, pour ralentir le véhicule, tout en stockant l'énergie. La nouveauté du présent travail est de considérer le moteur-roue électrique comme seul signal de contrôle dans des phases d'accélération et des phases de ralentissement, simplifiant l'architecture de la conception du véhicule et des lois de contrôle. Pour répondre à la demande conducteur tout en préservant un comportement sain du véhicule, des stratégies d'estimation de la limite d'adhérence seront présentées. En fonction de cette adhérence maximale disponible entre la route et les pneus, un couple adéquat sera calculé pour assurer un comportement stable dans des phases d'accélération aussi bien que de freinage. L'aspect critique étudié dans ce travail est la non-linéarité des caractéristiques d'interaction entre la route et le pneu et la complexité de son estimation dans des conditions variables. La stratégie d'estimation devra détecter tous les changements d'adhérence de route et la loi de contrôle calculée devra maintenir la stabilité véhicule même lorsque la friction maximale change. Certaines formes de perturbation et de bruit seront également prises en compte afin de tester la robustesse des approches d'estimation et de contrôle proposés. Parmi les systèmes de sécurité active les plus importants en phase d'accélération, le système de contrôle de traction (TCS) rétablit la traction si les roues commencent à patiner et le programme de stabilité électronique (ESP) intervient pour prévenir une perte menaçante du contrôle latéral du véhicule. Dans le cas du freinage, le système décisif est le système d'antiblocage (ou ABS), qui empêche le blocage des roues. On peut trouver d'autres systèmes embarqués, comme le système de distribution de force de freinage électronique (EBD), qui assure une distribution optimale de la force de freinage transmise aux roues, pour éviter de déraper et assure un ralentissement stable du véhicule. Les systèmes embarqués qui fournissent les estimations doivent être robustes aux bruits de mesure et aux perturbations. A fortiori, ces calculs doivent être faits en temps réel, donc une complexité réduite et une réponse rapide de la loi de contrôle sont nécessaires. Enfin, l'environnement dans lequel le véhicule fonctionne est dynamique, les caractéristiques d'adhérence peuvent varier en fonction de l'état de la route et de la météo. Ainsi, on ne peut prévoir les réactions du conducteur pouvant influencer la réponse globale du véhicule dans des situations d'urgence. Le contrôleur devrait prendre en compte tous ces aspects pour préserver un comportement stable du véhicule. Bien que le contrôle latéral du véhicule présente une importance majeure dans la stabilité globale du véhicule, le présent travail est concentré sur le contrôle longitudinal du véhicule, puisqu'il représente le point de départ de la dynamique véhicule.The main objective of the present thesis focuses on the integration of the in-wheel electric motors into the conception and control of road vehicles. The present thesis is the subject of the grant 186-654 (2010-2013) between the Laboratory of Signals and Systems (L2S-CNRS) and the French Institute of Petrol and New Energies (IFPEN). The thesis work has originally started from a vehicular electrification project, equipped with in-wheel electric motors at the rear axle, to obtain a full electric urban use and a standard extra-urban use with energy recovery at the rear axle in braking phases. The standard internal combustion engines have the disadvantage that complex estimation techniques are necessary to compute the instantaneous engine torque. At the same time, the actuators that control the braking system have some delays due to the hydraulic and mechanical circuits. These aspects represent the primary motivation for the introduction and study of the integration of the electric motor as unique propelling source for the vehicle. The advantages brought by the use of the electric motor are revealed and new techniques of control are set up to maximize its novelty. Control laws are constructed starting from the key feature of the electric motor, which is the fact that the torque transmitted at the wheel can be measured, depending on the current that passes through the motor. Another important feature of the electric motor is its response time, the independent control, as well as the fact that it can produce negative torques, in generator mode, to help decelerate the vehicle and store energy at the same time. Therefore, the novelty of the present work is that the in-wheel electric motor is considered to be the only control actuator signal in acceleration and deceleration phases, simplifying the architecture of the design of the vehicle and of the control laws. The control laws are focused on simplicity and rapidity in order to generate the torques which are transmitted at the wheels. To compute the adequate torques, estimation strategies are set up to produce reliable maximum friction estimation. Function of this maximum adherence available at the contact between the road and the tires, an adequate torque will be computed in order to achieve a stable wheel behavior in acceleration as well as in deceleration phases. The critical issue that was studied in this work was the non-linearity of the tire-road interaction characteristics and its complexity to estimate when it varies. The estimation strategy will have to detect all changes in the road-surface adherence and the computed control law should maintain the stability of the wheel even when the maximum friction changes. Perturbations and noise are also treated in order to test the robustness of the proposed estimation and control approaches.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF

Motion planning for experimental airpath control of a diesel homogeneous charge-compression ignition engine

International audienceA strategy based on motion planning is proposed for airpath control of turbocharged diesel engines equipped with exhaust gas recirculation. The objective is to manage the air and burned gas masses in the cylinder. The model considered uses simple balance equations for the intake manifold. The fully actuated dynamics are easily inverted, yielding straightforward open-loop control laws. This approach is complemented by experimentally derived look-up tables to apply driver requests into the problem of designing transitions between operating points. Experimental tests are reported for a four-cylinder homogeneous charge-compression ignition engine. Conclusions stress the possibility of taking into account the non-minimum phase effects of this system by a control law that is simple, yet efficient in practice

Experimental motion planning in airpath control for HCCI engine

Abstract — A motion planning based control strategy is proposed for the airpath control of turbocharged Diesel engines using exhaust gas recirculation (EGR). The considered model uses simple balance equations. The fully actuated dynamics are easily inverted, yielding straightforward open-loop control laws. This approach is complemented by experimentally derived lookup tables to cast the driver’s requests into transients between operating points. Estimation of required variables from the intake pressure measurements is addressed and experimental tests are reported on a 4-cylinder engine in Homogeneous Charge Compression Ignition (HCCI) mode. Conclusions stress the possibility of taking into account the non-minimum phase effects of this system by a simple, yet efficient in practice, control law. Observed transients are accurate and fast. I

Periodic input estimation for linear periodic systems: Automotive engine applications

International audienceIn this paper, we consider periodic linear systems driven by T0-periodic signals that we desire to reconstruct. The systems under consideration are of the form dx/dt=A(t)x+A0(t)w(t), y=C(t)x, x ∈ Rn, w ∈ Rm, y ∈ Rp, (m leq p leq n) where A(t), A0(t), and C(t) are T0-periodic matrices. The period T0 is known. The T0-periodic input signal w(t) is unknown but is assumed to admit a finite dimensional Fourier decomposition. Our contribution is a technique to estimate w from the measurements y. In both full state measurement and partial state measurement cases, we propose an efficient observer for the coefficients of the Fourier decomposition of w(t). The proposed techniques are particularly attractive for automotive engine applications where sampling time is short. In this situation, standard estimation techniques based on Kalman filters are often discarded (because of their relative high computational burden). Relevance of our approach is supported by two practical cases of application. Detailed convergence analysis is also provided. Under standard observability conditions, we prove asymptotic convergence when the tuning parameters are chosen sufficiently small