Showing papers on "Vehicle dynamics published in 1999"
TL;DR: In this article, the application of stochastic state estimators in vehicle dynamics control is discussed, where it is often unrealistic to assume that all vehicle states and the disturbances acting on it can be measured.
Abstract: This paper deals with the application of stochastic state estimators in vehicle dynamics control. It is often unrealistic to assume that all vehicle states and the disturbances acting on it can be measured. System states that cannot be measured directly, can be estimated by a Kalman Filter. The idea of the Kalman filter is to implement a model of the real system in an on-board computer in parallel with the system itself. This paper will give 3 examples of this principle applied to automotive systems.
187 citations
01 Aug 1999
TL;DR: The control concept presented is composed of three feedback loops: Continuous operation steering control, emergency steering control and emergency braking control, which ensures that the vehicle's roll damping is robustly improved for a wide range of speed and height of the center of gravity.
Abstract: Steering and braking control is applied to avoid rollover of road vehicles. The control concept presented is composed of three feedback loops: Continuous operation steering control, emergency steering control and emergency braking control. In continuous operation the roll rate and the roll acceleration are fed back by velocity scheduled gains to the front wheel steering angle. Thereby, the vehicle's roll damping is robustly improved for a wide range of speed and height of the center of gravity. The latter may change for example with a truck from ride to ride. A rollover coefficient is defined that basically depends on the lateral acceleration at the center of gravity of the vehicle's sprung mass. For critical values of this variable the emergency steering and braking system is activated. The rollover coefficient is also used for nonlinear feedback to the front wheel steering angle. The control concept is evaluated by linear sensitivity analysis and by simulations. Additionally, absolute stability of the steering control concept is verified using Popov's criterion.
172 citations
TL;DR: INTELSIM moved vehicles simultaneously and produces solutions for a continuous time frame and produced the best agreement with the field data and required the least amount of calibration effort.
Abstract: Presented in this paper are the car-following methods and algorithms of the NETSIM, INTRAS, FRESIM, CARSIM, and INTELSIM models. Moreover, the car-following performance of these models is compared with the field data. NETSIM, INTRAS, FRESIM, and CARSIM car-following models first move the leader and then update the follower in one simulation time step. Because of this approach, these car-following models cannot be used to command vehicles in real-time intelligent transportation systems applications. Moreover, brake reaction times are limited by the simulation time step because of this method of updating the vehicles. INTELSIM was developed to overcome these deficiencies. INTELSIM moves vehicles simultaneously and produces solutions for a continuous time frame. INTELSIM produced the best agreement with the field data and required the least amount of calibration effort.
128 citations
TL;DR: In this paper, the authors present an approach to the assessment of the manoeuvrability of vehicles which is not based on the simulation of open-loop manoeuvres, nor does it rely on the modelling of the driver as a control system.
Abstract: This paper presents a novel approach to the assessment of the manoeuvrability of vehicles which is not based on the simulation of open-loop manoeuvres, nor does it rely on the modelling of the driver as a control system. Instead, the essence of the method is the solution of a two-point optimal control boundary value problem, in which a vehicle, subject to physical constraints like tyre adherence and road borders, among others, is required to go between given initial and final positions as fast as possible. The control inputs - i.e., the driver's actions - that make the vehicle move between the two states in the most efficient way are found as a part of the solution procedure and represent the actions of a sort of ideal, perfect driver. The resulting motion is called the optimal manoeuvre and, besides being the most efficient way that the given vehicle has for travelling between the two points according to the chosen optimal criterion, may be taken as a reference for meaningful comparisons with other vehic...
117 citations
TL;DR: The comprehensive process of developing such automated steering control system is described, which serves as a good case study for mechatronic system design integrating mechanical components, electronic devices, intelligence, and feedback control to perform vehicle automation functions.
Abstract: Automated steering control is a crucial element of vehicle automation. The California PATH Program at the University of California at Berkeley has developed one such system using magnetic markers embedded under the roadway for lateral guidance. This system was demonstrated during the August 1997 National Automated Highway System Consortium Feasibility Demonstration, San Diego, CA, without a single failure. Developing a successful demonstration system not only required theoretical understanding of the various control problems involved, but also strong appreciation of all practical issues. In the paper, the comprehensive process of developing such automated steering control system is described. This process consists of control objectives' determination, system structure definition, vehicle dynamics validation, lateral sensing system development, steering actuator design, test track installation, control algorithm development, software/hardware integration, and vehicle testing. The entire process also serves as a good case study for mechatronic system design integrating mechanical components, electronic devices, intelligence, and feedback control to perform vehicle automation functions.
112 citations
TL;DR: In this paper, a survey of full scale as well as small scale model roller rigs is presented, including performance, most important experimental work and the emphasis of application, scaling strategies of model test rigs and the differences involved in roller rig experiments.
Abstract: Roller rigs have been built world-wide to research into the dynamics of railway vehicles and they have particularly been applied to the development of high-speed trains. This survey takes into consideration both full scale as well as small scale model roller rigs. Besides performance, most important experimental work and the emphasis of application, the scaling strategies of model test rigs and the differences involved in roller rig experiments are treated. Suggestions for potential future uses and developments are also given for this tool which is useful for demonstration and analysis of railway vehicle dynamic behaviour.
111 citations
01 Dec 1999
TL;DR: In this article, the authors reviewed recent trends of vehicle chassis control, paying attention to the basic nature of the vehicle dynamics, tyre characteristics and the effectiveness and limit of four-wheel steer.
Abstract: Recent trends of vehicle chassis control are reviewed, paying attention to the basic nature of the vehicle dynamics, tyre characteristics and the effectiveness and limit of four-wheel steer...
109 citations
TL;DR: In this article, a brief outline of nonlinear dynamics and its applications to vehicle systems dynamics problems is presented, and various equilibrium states are defined, and the important case of multiple equilibrium states and their dependence on a parameter is discussed.
Abstract: We present a brief outline of nonlinear dynamics and its applications to vehicle systems dynamics problems. The concept of a phase space is introduced in order to illustrate the dynamics of nonlinear systems in a way that is easy to perceive. Various equilibrium states are defined, and the important case of multiple equilibrium states and their dependence on a parameter is discussed. It is argued that the analysis of nonlinear dynamic problems always should start with an analysis of the equilibrium states of the full nonlinear problem whereby great care must be taken in the choice of the numerical solvers. When the equilibrium states are known certain linearizations around one chosen state may be applied carefully in order to facilitate or speed up the numerical solution of the dynamical problem. It is argued, however, that certain problems cannot be linearized. The applications of nonlinear dynamics in vehicle simulations is discussed, and it is argued that it is necessary to know the equilibrium states ...
108 citations
TL;DR: Stability of railway and road vehicles has been investigated since the 19th century as discussed by the authors, with the first hey-day with the work of Carter and Rocard on stability of locomotives.
Abstract: Stability of running of vehicles is one of the important design criteria of railway and road vehicles. Railway vehicle stability is based on kinematics as well as contact mechanics. It reaches back to the 19th century and had its first hey-day with the work of Carter and Rocard on stability of locomotives. A rediscovery of their knowledge, which seemed to have been forgotten, was inevitable due to increased vehicle speeds since the early Fifties. — Though investigations on road vehicle stability only began approximately in 1930 with the treatment of the shimmy phenomenon, realistic solutions were available at the same time as for railway vehicles. Besides considering historical aspects we discuss in the paper links which exist between both approaches; open questions are described.
93 citations
TL;DR: The paper describes concept, evaluation, and operation of a digital hardware-in-the-loop simulator for testing control-relevant parts of the vehicle and its inherent causality variations due to the combination of discrete switching effects and differential equations for currents or mechanical system parts.
Abstract: Control systems for converter-controlled rail vehicles are orders of magnitude more complex than controllers for previous generations of vehicles. While the dynamic behavior of previous generations of vehicles was to a large extent determined by its power components alone, an important part of the dynamics of modern vehicles is shaped by real-time software, distributed computing and intercontroller communication. To ensure proper operation of the vehicle on track, an integration test of the vehicle control system is performed before initial roll-out. In order to achieve a maximum test depth and to minimize risk and cost, this test is achieved by connecting the original vehicle control system to a real-time dynamic vehicle simulator in closed-loop operation. The paper describes concept, evaluation, and operation of a digital hardware-in-the-loop simulator for testing control-relevant parts of the vehicle. Particular emphasis is put on the hybrid nature of the underlying simulation problem and its inherent causality variations due to the combination of discrete switching effects, e.g., in diodes and controlled converters, with continuous system parts, e.g., differential equations for currents or mechanical system parts.
87 citations
TL;DR: The AYC (Active Yaw Control) and ASC (Active Stability Control) systems as mentioned in this paper control the driving and braking forces acting upon the right and left wheels in such a way that cornering force can be controlled directly by the driver.
Abstract: In line with improvements in vehicle performance and increasing diversification in vehicle applications, improvements in active safety are becoming increasingly important. For its part, Mitsubishi Motors has developed a variety of wheel control technologies that enhance both safety and performance by exploiting the inherent properties of wheels and tyres. This paper describes two of Mitsubishi Motors’ latest developments: the AYC (Active Yaw Control) system and the ASC (Active Stability Control) system. These systems control the driving and braking forces acting upon the right and left wheels in such a way that cornering force can be controlled directly by the driver. As a result, they enable significantly safer and more enjoyable driving.
TL;DR: In this article, comparative experiments with three different thrust control algorithms over a wide range of unsteady operating conditions suggest that model-based control algorithms offer transient thrust-control performance superior to that of their nonmodel-based counterpart.
Abstract: This paper reports comparative experiments with two novel and one conventional thrust control algorithms for the unsteady (transient) control of thrust generated by conventional bladed-propeller marine thrusters. First, comparative experiments with three different thrust control algorithms over a wide range of unsteady operating conditions suggest that model-based control algorithms offer transient thrust-control performance superior to that of their nonmodel-based counterpart. Second, hybrid simulations combining actual real-time experimental thruster responses with simulated one-dimensional real-time vehicle dynamics suggest that model-based thrust control algorithms offer vehicle position control superior to that of its nonmodel-based counterpart.
02 Jun 1999
TL;DR: In this article, a combined steering and speed controller for the automated highway system (AHS) program of the California Partners for Advanced Transportation and Highways (PATH) is presented.
Abstract: This paper covers developments in the control integration part of the automated highway system (AHS) program of the California Partners for Advanced Transportation and Highways (PATH). The control integration project investigates the potential for improving controller performance through an integrated design of a combined steering and speed controller specifically designed to address the coupling between the steering and speed controls. The following results are presented: (1) the identification and characterization of the various coupling effects through an analysis of vehicle dynamics; (2) the design of a combined controller which compensates for the coupling effects; and, (3) the evaluation of the improvements contributed by the coupling compensation through simulations and through experiments on full-scale test vehicles. Sliding control and dynamic surface control (DSC) methods are used to facilitate the inclusion of the complex, nonlinear coupling effects in the controller derivation. A multiple-rate observer is designed to obtain a lateral velocity estimate which is essential to the implementation of the controller on the test vehicle. Simulations and experiments show that the coupling compensation does improve controller performance and that the combined controller is robust to modeling imperfections and vehicle parameter variations. The combined controller described in this paper may be the ideal basis for future implementation of the automated highway system.
01 Jan 1999
TL;DR: In this paper, a combined method of model observer and direct integration method is used to overcome difficulties in slip angle estimation due to nonlinear characteristics of tires and the influence of road surface slant.
Abstract: In this paper, the author presents a strategy for vehicle slip angel estimation which can be applied to direct yaw-moment control systems. The strategy employs a combined method of model observer and direct integration method. This method is used to overcome difficulties in slip angle estimation due to nonlinear characteristics of tires and the influence of road surface slant.
01 Aug 1999
TL;DR: Robust reduction of transient rollover risk is shown by evaluation of the sensitivity function at various operating points and the control law presented is based on feedback of the roll rate and the roll acceleration.
Abstract: Active steering is applied to robustly reduce the rollover risk of vehicles with an elevated center of gravity. An actuator sets an auxiliary steering angle which is mechanically added to the steering angle commanded by the driver. The control law presented, is based on feedback of the roll rate and the roll acceleration. The controller gains are scheduled with the speed and the vehicle's CG height. The controller gains are found by the parameter space approach and constrained optimization in frequency domain. Robust reduction of transient rollover risk is shown by evaluation of the sensitivity function at various operating points. Simulation of a double lane change maneuver illustrates the benefits in time domain.
TL;DR: In this paper, a mathematical model concerning steering torque is developed; it takes into account the actual kinematic behaviour of the vehicle and the properties of motorcycle tyres, and several numerical results are presented, and the influence of tyre properties and some geometrical and inertial properties on steering torque are discussed.
Abstract: When driving along a circular path, the driver of a motorcycle controls the vehicle mainly by means of steering torque. If low steering torque is necessary, the driver feels that the vehicle is manoeuvrable. In this paper, a mathematical model concerning steering torque is developed; it takes into account the actual kinematic behaviour of the vehicle and the properties of motorcycle tyres. Tyre forces act at the contact points of toroidal tyres, which are calculated according to kinematic analysis. Non-linear equations are solved using an iterative approach. Several numerical results are presented, and the influence of tyre properties and some geometrical and inertial properties of the vehicle on steering torque are discussed.
Patent•
29 Mar 1999
TL;DR: In this paper, a road vehicle moves along a defined section of road that has a number of different sections including curves, and the vehicle receives information from several mobile communication beacons (12) allowing the vehicle to be informed of conditions related to the vehicle dynamics.
Abstract: A road vehicle moves along a defined section of road that has a number of different sections including curves. The vehicle receives information from a number of different mobile communication beacons (12). This allows the vehicle to be informed of conditions related to the vehicle dynamics.
TL;DR: In this paper, the authors investigated the onset and effects of separation between the moving vehicle and bridge and proposed an algorithm to account for the impact on the re-establishment of contact.
TL;DR: In this article, a set of linear maneuvering equations representing the four-wheel steering motions and independent wheel torques for lateral/directional plus roll dynamics were obtained and the steering angles were actively controlled by steering wheel commands through the actuator mechanisms for the lateral and directional and roll motions.
01 Jan 1999
TL;DR: In this paper, a new H/sub /spl infin// yaw-moment control scheme using brake torque for improving vehicle performance and stability especially in high speed driving is proposed.
Abstract: This paper proposes a new H/sub /spl infin// yaw-moment control scheme using brake torque for improving vehicle performance and stability especially in high speed driving. Its characteristics is that only one brake is used for control depending on the vehicle state. Steering angles are modeled as a disturbance input to the system and the controller minimizes the difference between the performance of the actual vehicle behavior and that of its 'model' behavior under the disturbance input. Various simulations with a nonlinear 8-DOF vehicle model show that the controller enhances the vehicle performance and stability.
01 Mar 1999
TL;DR: This paper gives a statistical description of the five most frequently occurring rear-end precrash scenarios based on vehicle and driver characteristics and can be applied towards estimating the safety benefits of advanced technology rear- end collision avoidance systems.
Abstract: This paper studies different driver and vehicle characteristics as they impact pre-crash scenarios of rear-end collisions. It gives a statistical description of the five most frequently occurring rear-end precrash scenarios based on vehicle and driver characteristics. Variables were drawn from the General Estimates System (CRASH) crash database. Results from the study can be applied towards estimating the safety benefits of advanced technology rear-end collision avoidance systems for reducing the number of crashes and mitigating the level of severity.
TL;DR: In this article, a worst-case evaluation method is presented to identify worstcase maneuvers so that the performance of dynamic systems under extreme conditions can be evaluated, where classical optimal control and game theories are used to construct algorithms to obtain linear solutions analytically.
Abstract: A worst-case evaluation method is presented in this paper. The objective of this method is to identify worst-case maneuvers so that the performance of dynamic systems under extreme conditions can be evaluated. Depending on the dynamics and information structure of the system, the worst-case evaluation problems can be classified into four sub-cases. Classical optimal control and game theories are used to construct algorithms to obtain linear solutions analytically. When the plant and/or the control algorithm is nonlinear, the true worst-case solution can be obtained from numerical methods. Two case-study examples are presented. A linear example presents the time domain and frequency domain results comparing the four linear algorithms. The generation of the worst-case steering and braking maneuver to rollover an articulated vehicle is then presented as a "real" application example. Interested reader can download the PC-based software and generate the simulation results by visiting the website
TL;DR: In this article, a sliding-mode theory-based control system for manoeuvering with independent brake for the avoidance of spin and drift-out is presented, which is also equipped with parameter identification for correcting model errors.
Abstract: It has become popular to control vehicle manoeuvering with independent brakes for the avoidance of spin and drift-out. To ensure effective control, we applied sliding-mode theory, which enabled a robust control system against various driving conditions including changes in velocity, road friction and vehicle weight. By estimating the tyre status with a simple tyre model, the side slip angle of vehicle and road friction, we made it possible to easily install the system on vehicles. Our system is also equipped with parameter identification for correcting model errors. We confirmed the effectiveness of our system through full vehicle simulation and field tests.
22 Aug 1999
TL;DR: In this article, the authors address realistic subjects encountered in the challenge of achieving technology improvement in a vehicle stability control system, including driver intent recognition, control development philosophy, vehicle side slip estimation, and road bank angle estimation.
Abstract: This paper addresses realistic subjects encountered in the challenge of achieving technology improvement in a vehicle stability control system. They include driver intent recognition, control development philosophy, vehicle side slip estimation, and road bank angle estimation.
TL;DR: A nonlinear vehicle model with 22 motion degrees of freedom, used for synthesis of the system autopilot, and proposed scheme of the distributed hierarchy control enables control of entire vehicle dynamics as a multibody dynamic system.
Abstract: A nonlinear vehicle model with 22 motion degrees of freedom, used for synthesis of the system autopilot, was described in the paper. It was demonstrated how a controller can be designed on the basis of such relatively complex dynamic model, ensuring simultaneous motion stability of the vehicle in longitudinal, lateral and vertical directions, as well as the stability of roll, pitch, and yaw dynamics of the vehicle about corresponding axes. Vehicle automatic control was realized at two hierarchical levels: tactical and executional. Proposed scheme of the distributed hierarchy control enables control of entire vehicle dynamics as a multibody dynamic system. Control has been synthesized in such a way that the system satisfies set criteria of dynamic behavior. The synthesized controller improves system motion caused by action of casual, external perturbations, and internal inertial and centrifugal forces which appear as a consequence of an inadequately adapted ride velocity to the road geometry. Also, necessary information for estimation of unknown time-variant parameters of the dynamic model and of tire-road interaction were briefly given in the paper. Simulation results were presented and analyzed for one example of characteristic trajectory with perturbation of type of an uneven and slippery road, as well as a wind gust.
TL;DR: Results in developing an automatic guidance and control system for Romeo are presented and the system performance in the proximity of the coast, where there is only a very shallow column of free water between the ice-pack and the sea-bed, is discussed.
Abstract: In this article, after a brief overview of trends in underwater unmanned vehicle (UUV) design and applications, results in developing an automatic guidance and control system for Romeo are presented. Attention is focused on the design, development, and testing in the operating conditions of a bottom and ice-canopy following system and on the development of methodologies for the at-field identification of the vehicle dynamics in order to guarantee high motion-control performance, even in the presence of variations in the vehicle configuration. In particular, the system performance in the proximity of the coast, where there is only a very shallow column of free water between the ice-pack and the sea-bed, is discussed.
02 Jun 1999
TL;DR: The paper develops the mathematical framework that is required for integrated vision/inertial navigation system design and details a design example for an air vehicle landing on an aircraft carrier.
Abstract: Addresses the problem of navigation system design for autonomous aircraft landing. New nonlinear filter structures are introduced to estimate the position of an aircraft with respect to a possibly moving landing site, such as a naval vessel, based on measurements provided by airborne vision and inertial sensors. By exploring the geometry of the navigation problem, the navigation filter dynamics are cast in the framework of linear parametrically varying systems (LPVs). Using this set-up, filter performance and stability are studied in an H/sub /spl infin// setting by resorting to the theory of linear matrix inequalities (LMIs). The design of nonlinear, globally stable filters to meet adequate H/sub /spl infin// performance measures is thus converted into that of determining the feasibility of a related set of LMIs and finding a solution to them, if it exists. This is done by resorting to widely available numerical tools that borrow from convex optimization techniques. The paper develops the mathematical framework that is required for integrated vision/inertial navigation system design and details a design example for an air vehicle landing on an aircraft carrier.
TL;DR: In this article, an adaptive control law is derived for the rotational maneuver of the spacecraft and a stabilizer is designed using elastic mode velocity feedback for the stabilization of the zero dynamics.
Abstract: This work treats the question of large angle rotational maneuver and stabilization of an elastic spacecraft (spacecraft-beam-tip body configuration). It is assumed that the parameters of the system are completely unknown. An adaptive control law is derived for the rotational maneuver of the spacecraft. Using the adaptive controller, asymptotically decoupled control of the pitch angle of the space vehicle is accomplished, however this maneuver causes elastic deformation of the beam connecting the orbiter and tip body. For the stabilization of the zero dynamics (flexible dynamics), a stabilizer is designed using elastic mode velocity feedback. In the closed-loop system including the adaptive controller and the stabilizer, reference pitch angle trajectory tracking and vibration suppression are accomplished. Simulation results are presented to show the maneuver capability of the control system.
15 Jun 1999-Jsme International Journal Series C-mechanical Systems Machine Elements and Manufacturing
TL;DR: In this paper, an integrated control system of active rear wheel steering and yaw moment control using braking forces is presented, which is designed using model matching control theory to make the vehicle performance follow a desired dynamic model even during large decelerations or lateral accelerations.
Abstract: An integrated control system of active rear wheel steering and yaw moment control using braking forces is presented in this paper.Due to the tire nonlinearity that is mainly due to the saturation of cornering forces, the improvement of vehicle handling and stability is limited to a certain extent when using only rear wheel steering control.Yaw moment control using braking forces is effective not only in linear but also nonlinear ranges of the tire friction circle.Considering the tire friction circle, the control system is designed using model matching control theory to make the vehicle performance follow a desired dynamic model even during large decelerations or lateral accelerations.Various computer simulations in severe driving conditions were carried out and verified that vehicle handling and stability are much improved by the integrated control system.