An LP V/H∞ integrated Vehicle Dynamic Controller

International audienceThis paper is concerned with the design and analysis of a new multivariable LP V /H∞ (Linear Parameter Varying) robust control design strategy for Global Chassis Control. The main objective of this study is to handle critical driving situations by activating several controller subsystems in a hierarchical way. The proposed solution consists indeed in a two-step control strategy that uses semi-active suspensions, active steering and electro-mechanical braking actuators. The main idea of the strategy is to schedule the 3 control actions (braking, steering and suspension) according to the driving situation evaluated by a specific monitor. Indeed, on one hand, rear braking and front steering are used to enhance the vehicle yaw stability and lateral dynamics, and on the other hand, the semi-active suspensions to improve comfort and car handling performances. Thanks to the LP V /H∞ framework, this new approach allows to reach a smooth coordination between the various actuators, to ensure robustness and stability of the proposed solution, and to significantly improve the vehicle dynamical behavior. Simulations have been performed on a complex full vehicle model which has been validated using data obtained from experimental tests on a real Renault Mégane Coupé. Moreover, the suspension system uses Magneto-Rheological dampers whose characteristics have been obtained through experimental identification tests. A comparison between the proposed LPV/H∞ control strategy and a classical LTI/H∞ controller is performed using the same simulation scenarios and confirms the effectiveness of this approach

A LPV/Hinf fault tolerant control of vehicle roll dynamics under semi-active damper malfunction

International audienceThis paper proposes a LPV/Hinf fault tolerant control strategy for roll dynamics handling under semi-active damper's malfunction. Indeed, in case of damper's malfunction, a lateral load transfer is generated, that amplifies the risks of vehicle roll over. In this study, the suspension systems efficiency is monitored through the lateral (or longitudinal) load transfer induced by a damper's malfunction. The information given by the monitoring system is used in a partly fixed LPV/Hinf controller structure that allows to manage the distribution of the four dampers forces in order to handle the over load caused by one damper's malfunction. The proposed LPV/Hinf controller then uses the 3 remaining healthy semi-active dampers in a real time reconfiguration. Moreover, the performances of the car vertical dynamics (roll, bounce, pitch) are adapted to the varying parameter given by the monitoring of the suspension system efficiency, which allows to modify online the damping properties (soft/hard) to limit the induced load transfer. Simulations are performed on a complex nonlinear full vehicle model, equipped by 4 magneto-rheological semi-active dampers. This vehicle undergoes critical driving situations, and only one damper is considered faulty at ones. The simulation results show the reliability and the robustness of the proposed solution

LPV methods for fault-tolerant vehicle dynamic control

International audienceThis paper aims at presenting the interest of the Linear Parameter Varying methods for vehicle dynamics control, in particular when some actuators may be in failure. The cases of the semi-active suspension control problem and the yaw control using braking, steering and suspension actuators will be presented. In the first part, we will consider the semi-active suspension control problem, where some sensors or actuator (damper leakage) faults are considered. From a quarter-car vehicle model including a non linear semi-active damper model, an LPV model will be described, accounting for some actuator fault represented as some varying parameters. A single LPV fault-tolerant control approach is then developed to manage the system performances and constraints. In the second part the synthesis of a robust gain-scheduled H1 MIMO vehicle dynamic stability controller (VDSC), involving front steering, rear braking, and four active suspension actuators, is proposed to improve the yaw stability and lateral performances. An original LPV method for actuator coordination is proposed, when the actuator limitations and eventually failures, are taken into account. Some simulations on a complex full vehicle model (which has been validated on a real car), subject to critical driving situations (in particular a loss of some actuator), show the efficiency and robustness of the proposed solution

A novel design and control solution for an aircraft sidestick actuator based on Halbach permanent magnet machine

This paper is concerned with the design and control of a new sidestick actuators used to handle a civilian aircraft behaviour. Indeed, a discrete robust adaptive sliding mode control for a new designed aircraft sidestick based on synchronous Halbach permanent magnet machine. The main objective is to provide a new design structure and a control solution that ensures maintaining high performance specifications for the actuator and respects the set of constraints required by the considered aeronautical application. Indeed, this study achieved in a partnership with an industrial center of excellence for Fly by Wire Cockpit Controls (side sticks, rudder controls, thrust controls), proposes a novel design that enhances the characteristics of the actuator’s structure and the human machine interface between the pilot and the aircraft. Then, a new control strategy is proposed to optimize the efficiency of this actuator for the considered application. It is based on a discrete optimal adaptive sliding mode control considering time delays and uncertainties in the model by using a delay ahead predictor. The proposed strategy combines an optimal sliding mode surface with the delay ahead predictor in an adaptive control structure. Indeed, a varying parameter is used to achieve an ”on-line” adaption to the varying level of disturbances that affects the system. Then, since the sidestick actuator is designed to handle an aircraft displacement, the proposed control strategy is designed for position tracking. Simulations performed on the previously designed actuator prove the efficiency of the proposed technological solution for aircraft position control

Study and comparison of non linear and LPV control approaches for vehicle stability control

International audienceThis paper proposes a study and a comparison between two efficient and novel vehicle control dynamics strategies, namely, the non linear Flatness control strategy and the LPV/Hinf control strategy. The first one concerns a controller based on the differential algebraic flatness of non linear systems and an algebraic non linear estimation applied to commercial vehicles. The second one is a LPV/Hinf (Linear Varying Parameter with the Hinf norm ) control using a stability monitoring system to achieve the vehicle dynamics control objective. These two strategies use Active Steering and Electro- Mechanical Braking actuators and aim at improving the vehicle stability and steerability by designing a multivariable controller that acts simultaneously on the lateral and longitudinal dynam- ics of the car. Simulations are performed on a complex nonlinear full vehicle model, the same driving scenario is applied for the two control strategies. The model parameters are those of a Renault Mégane Coupé (see table.I), obtained by identification with real data. Promising simulations results are obtained. Comparison between the two proposed strategies and the uncontrolled vehicle show the reliability and the robustness of the proposed solutions, even if one is governed within the linear control framework while the other one is a non linear control approach

A new LPV/Hinf semi-active suspension control strategy with performance adaptation to roll behavior based on non linear algebraic road profile estimation

International audienceThis paper presents a new LPV/Hinf semi-active suspension control strategy for a commercial vehicle equipped with 4 Magneto-Rheological dampers. The proposed approach concerns road adaptation using on-line road profile identification based on a non linear algebraic observer with unknown input. Then, the suspensions forces distribution in each corner of vehicle is performed considering roll dynamics. In this LPV/H1 strategy, 2 varying parameters are used to model the semi-active behaviour of the MR dampers, and 2 other ones, namely, the road roughness identification and roll dynamics, are considered for the road adaptation and the full vehicle vertical dynamics control. Different ISO road classes are used to test the efficiency of the on-line non linear algebraic road profile identification. Simulations scenarios, applied on a non linear full vehicle model, are used to evaluate the LPV/H1 controller performances in term of passengers comfort and road holding improvement in different driving situations

An open benchmark for distributed formation flight control of Fixed-Wing Unmanned Aircraft Systems

The capability of autonomous formation flight has the potential to significantly enhance the utility and efficiency of small low-cost Unmanned Aerial Systems (UAS). Formations of small, inexpensive fixed-wing UAS allow for the sharing of remote sensing functionality, mission-level redundancy and range enhancements due to aerodynamic interactions widely exploited by migratory birds. This article presents a benchmark problem for scalable distributed flight control of formations of UAS with only local relative state information, one of the open problems in this field as of today. The benchmark is openly available and comprises a nonlinear six degrees of freedom dynamics model of an electric glider UAS. In this article we furthermore introduce a nominal guidance frame that does not require state information of other UAS and point out a fundamental issue related to wake vortex tracking during formation maneuvers. A set of LQ baseline controllers that are part of the benchmark is presented along with simulation results

LPV/H ∞ suspension robust control adaption of the dynamical lateral load transfers based on a differential algebraic estimation approach

version soumise de 8 pagesInternational audienceThis paper is concerned with a new global chassis strategy combining the LPV/H ∞ control framework and the differential algebraic estimation approach. The main objective is to enhance the vehicle performances by adapting its control to the dynamical lateral load transfers using a very efficient algebraic dynamical behaviour estimation strategy. Indeed, the lateral load transfers influence considerably the vehicle dynamical behaviour, stability and safety especially in dangerous driving situations. It is important to emphasize that the dynamical load transfers are different from the static ones generated mainly by the bank of the road. The computation of these dynamics must be based on the effective lateral acceleration and roll behaviour of the car. Such effective data cannot be given directly by the hardware sensors (which give correlated measures). The information on the real dynamical lateral load transfers is very important to ensure a good adaptation of the vehicle control and performances to the considered driving situation. A very interesting differential algebraic estimation approach allows to provide the effective needed measures for the control strategy using only sensors available on most of commercial cars. It is based on the differential flatness property of nonlinear systems in an algebraic context. Then, thanks to this estimation approach, the dynamical lateral load transfers can be calculated and used to adapt the vertical performances of the vehicle using the LPV/H ∞ for suspension systems control. Simulations performed on non linear vehicle models with data collected on a real car are used to validate the proposed estimation and control approaches. Results show the efficiency of this vehicle control strategy

A novel structure design and control strategy for an aircraft active sidestick

This paper is concerned with a new design of an aircraft active sidestick based on Permanent Magnet Synchronous Machine (PMSM) and proposes an innovative robust control strategy based on an adaptive optimal sliding mode controller. Indeed, such an application requires high performance specifications which impose many constraints (torque, torques ripples, temperature). Here, a new design for the sidestick actuator is provided with a specific structure: a double airgap rotating one adapted to the considered process. Then, an optimization is performed to enhance the set of specifications of the PMSM w.r.t the aeronautical application. Also, a new adaptive optimal robust control for the designed actuator is provided based on the linear quadratic approach combined with the sliding mode control method. Then, an adaptive disturbances rejection is performed with the proposed strategy. Due to the considered design of the actuator (1/12 of a complete PMSM), a position control is achieved based on the LQRSliding mode approach to meet the required performances and to manage the plant parameter variation and load disturbances. Also, a varying parameter is used to adapt "on-line" the considered control to the varying level of disturbance that affect the system. First simulation results of the considered strategy applied to the newly designed actuator (compared to other strategies) proves the efficiency of the proposed solution for position control of the actuator and robustness considering load disturbances

Development of Sliding Mode Control Strategies and Haptic Feedback for Permanent Magnet Synchronous Motor (PMSM) Actuated Sidestick

The avionics society is in constant demand to optimize aircraft performance and improve the interaction between pilots and aircraft. This paper aims with the design and implementation of a stable nonlinear sliding mode control strategy and haptic feedback on PMSM actuated sidesticks to improve the tracking performance. The controller currently used in aircraft is a cascade of PID controllers in a linearized system, which cannot be considered more than a local solution as it doesn’t necessarily prove the stability in realistic conditions. Several nonlinear strategies were attempted on the model which accurately represents the new generation sidestick system powered by the permanent magnet synchronous motor (PMSM) actuator. Eventually, sliding mode nonlinear control strategy is considered as it provides solid stability while ensuring the desired performance. Furthermore, the execution of haptic feedback aims at fulfilling the lack of communication from the aircraft to the pilots, especially at extreme flight conditions. The pilot’s arm is assumed as a mass-spring-damper system ( to consider muscles stiffness and damping with the human response time) where force feedback is provided to the pilot for the command input. In conclusion, all the above-mentioned strategies are tested on a real sidestick system based on an innovative direct-drive linear actuator