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ABSTRACT: Unsymmetrical loading on a car like mu-split braking, side wind forces, or unilateral loss of tire pressure results in unexpected yaw disturbances that require yaw stabilization either by the driver or by an automatic driver-assist system. The use of two-degrees-of-freedom control architecture known as the model regulator is investigated here as a robust steering controller for such yaw stabilization tasks in a driver-assist system. The yaw stability-enhancing steering controller is designed in the parameter space to satisfy a frequency-domain mixed sensitivity constraint. To evaluate the resulting controller design, a real-time hardware-in-the-loop simulator is developed. Steering tests with and without the controller in this hardware-in-the-loop setup allow the driver to see the effect of the proposed controller to improve vehicle-handling quality. The hardware-in-the-loop simulation setup can also be used for real-time driver-in-the-loop simulation of other vehicle control systems.
IEEE Transactions on Vehicular Technology 03/2009; · 1.92 Impact Factor
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ABSTRACT: This article presents a low-cost, real-time, multiple driver-in-the-loop vehicle simulator. This simulator is used to test ACC scenarios for highway traffic. The vehicle models and simulation maneuvers are created in Simulink. Moderate-complexity vehicle models with both lateral and longitudinal dynamics, incorporating engine and driveline subsystems were developed. A platoon of two vehicles are considered using an acceleration-limited, constant-headway-time control strategy. Several scenarios are designed and tested on the vehicle simulator for both straight-line cruising and cornering of the vehicles. The ACC simulator is easy to construct using off-the-shelf components and can be used for both educational and research purposes.
IEEE control systems 07/2006; · 2.49 Impact Factor
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ABSTRACT: This article describes several automotive controls-related senior design projects. In this project, a team of two students built several masked Simulink blocks comprising elements of a mean value engine model (MVEM) and assembled these blocks into a blockset in the Simulink block library. The MVEM blockset was used to create a virtual engine for which an idle-speed controller was designed. An interesting aspect of this project is that neither student was from the controls option, having taken only a compulsory introductory course on system dynamics and control. Yet, their first task after creating the MVEM engine model was to design a speed controller. The overall learning and design phases proceeded quickly due to the use of the sisotool graphical user interface (GU) in Matlab's control system toolbox. The aim of this project was to create an HIL and human-in-the-loop driving simulator for testing vehicle dynamics control algorithms, examining the effect of a steer-by-wire actuator on vehicle dynamics control (VDC) performance, investigating driver-controller interaction, and eventually for driver modeling.
IEEE control systems 11/2004; · 2.49 Impact Factor
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ABSTRACT: Robust steering control based on a specific two degree-of-freedom control structure is used here for improving the yaw dynamics of a passenger car. The usage of an auxiliary-steering actuation system for imparting the corrective action of the steering controller is assumed. The design study is based on six operating conditions for vehicle speed and the coefficient of friction between the tires and the road representing the boundary of the operating domain of the vehicle. The design is carried out by finding the region in controller parameter plane where Hurwitz stability and a mixed-sensitivity frequency-domain constraint are simultaneously satisfied. A velocity-based gain scheduling type implementation is used. Moreover, the steering controller has a fading effect that leaves the low-frequency driving task to the driver, intervening only when necessary. The effectiveness of the final design is demonstrated with linear simulations and nonlinear simulations using a highly realistic model of an actual car.
IEEE Transactions on Control Systems Technology 08/2004; · 1.77 Impact Factor
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ABSTRACT: Engine control and management systems are the earliest applications of control technology in road vehicles. The main aim of an engine control system is to achieve a desired level of fuel economy while keeping exhaust emissions at acceptable levels. An engine is a very complicated system with a large number of variables, nonlinear and time varying behaviour. The conflicting relation between fuel economy and emission reduction further complicates the situation. Reduction of the typically large number of experimental calibration tests requires the development of reliable and accurate models. Real time hardware in the loop testing of engine electronic control units also mandates the engine model to be real time capable. First, an MVEM based Simulink engine blockset prepared for this purpose is explained in this paper. The use of a virtual engine in hardware in the loop real time simulation of engine speed control is the main result reported in this paper.
Mechatronics, 2004. ICM '04. Proceedings of the IEEE International Conference on; 07/2004
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ABSTRACT: Yaw stability control systems are important components of active safety systems for road transport. A model regulator based yaw stability control system that was previously implemented and tested very successfully as a steering controller is adapted to work as an individual wheel braking controller in this paper. A two track nonlinear vehicle model is used to test the individual wheel braking actuated model regulator developed here. Simulation results are used to demonstrate the achievement of good yaw disturbance moment rejection by the proposed controller.
Control Applications, 2003. CCA 2003. Proceedings of 2003 IEEE Conference on; 07/2003
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ABSTRACT: Yaw stability control is an important consideration in active safety of road transport. As steer by wire systems are now commercially available, steering actuated yaw stability controllers are expected to become more significant. The steer by wire actuator bandwidth and saturation limits may set achievable performance constraints on such steering controllers. This paper focuses on hardware in the loop (HIL) testing of steering controllers to investigate such performance problems. A HIL steering controller test setup is presented in this paper for that purpose.
Control Applications, 2003. CCA 2003. Proceedings of 2003 IEEE Conference on; 07/2003
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ABSTRACT: Active safety of road transport requires, among other things, the improvement of road vehicle yaw stability by active control. One approach for yaw dynamics improvement is to use differential braking, thereby creating the moment that is necessary to counteract the undesired yaw motion. An alternative approach is to command additional steering angles to create the counteracting moment. The maximum benefit, of course, can be gained through coordinated and combined use of both methods of corrective yaw motion generation in a control strategy. This problem has been approached by using a revised model regulator here as the main controller that utilizes coordinated steering and individual wheel braking actuation, with the aim of achieving better vehicle yaw stability control. Independent use of the individual means of actuation are treated first. Possible strategies for combined and coordinated use of steering and individual wheel braking action in a vehicle yaw dynamics controller are then presented. Simulation results on a nonlinear two track vehicle model are used to illustrate the effectiveness of the coordinated approach.
Intelligent Vehicles Symposium, 2003. Proceedings. IEEE; 07/2003
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ABSTRACT: A robust 2-DOF add-on controller design based on the disturbance
observer is presented in this paper for improved performance in vehicle
automatic steering. The application example is the benchmark problem on
automatic steering of a city bus with large variations in mass and speed
and for which the reference maneuvers and specifications are available
in the literature. The analytical formulation of the compensator is
presented, followed by evaluation and demonstration of the enhanced
model regulation and disturbance rejection properties achieved by its
use. Improved steering dynamics can be achieved using yaw rate feedback
without the need for a yaw rate sensor. Noting that the steering angle
rate actuator saturation forms a major limitation of performance,
especially in the presence of the integrating actuator used in the city
bus example, the performance enhancement due to the disturbance
observer-based add-on compensator is investigated in the presence of
actuator saturation. Finally, a disturbance feedforward-based add-on
compensator is also presented for well-defined reference trajectories
like the entering a bus stop bay maneuver, enabling preview
IEEE Transactions on Control Systems Technology 02/2002; · 1.77 Impact Factor
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ABSTRACT: Unsymmetrical loading on a car (like μ-split braking, side wind forces or unilateral loss of tire pressure) result in unexpected yaw disturbances that require yaw stabilization either by the driver or by an automatic driver assist system. The use of the two degree of freedom control architecture known as the model regulator is investigated here as a robust steering controller for such yaw stabilization tasks in a driver-assist system. Robust controller design for satisfying a mixed sensitivity constraint is presented. The technique of mapping frequency domain bounds to parameter space is used in the design calculations and explicit formulas for the point condition solution are obtained for the steering model regulator. Design and subsequent simulation studies are conducted at six exemplary operating conditions. While linear simulation results based on the linearized single track model are given, the nonlinear single track model based simulation results are also given to demonstrate the fulfillment of the desired control tasks of yaw moment disturbance rejection and model regulation. The nonlinear single track model simulations are also used to demonstrate the effectiveness of the gain scheduled implementation of the steering model regulator used.
Control Applications, 2002. Proceedings of the 2002 International Conference on; 02/2002
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ABSTRACT: The disturbance observer is a widely used form of a two degree of
freedom control architecture which reduces sensitivity to modeling error
while enhancing disturbance rejection properties. While standard robust
stability analysis of the disturbance observer in the presence of
unstructured modeling error is well known and results in a simple design
guideline, similar results are lacking for the case of structured, real
parametric uncertainty in the plant. Considering the case in which the
plant has real parametric uncertainty, the real structured singular
value method is applied to stability and performance robustness
analysis, resulting in less conservative results. The model of an
electrohydraulic positioning system with large parametric variation
especially in its damping ratio is used to illustrate the concept. The
results are extended to the case in which the plant under disturbance
observer regulation is also under feedback control, as is usually the
case in applications
American Control Conference, 2001. Proceedings of the 2001; 02/2001
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ABSTRACT: This paper presents a new collision warning (CW) algorithm for rear-end collisions. Considering the large number of traffic accidents that result due to driver errors or situations that are unpredictable for the driver, many CW Algorithms were developed in the past years. However, these algorithms did not adequately take into account vehicles with an adaptive cruise control (ACC) System. This paper aims to modify these algorithms assuming the presence of an ACC system and to develop a new algorithm considering human factors and maneuvers of vehicles with ACC in critical situations
Intelligent Vehicles Symposium, 2006 IEEE;
