Fuzzy identification of uncertain ground parameters for autonomous mobile machines. - In: International journal of vehicle autonomous systems, ISSN 1471-0226, Bd. 9 (2011), 3/4, S. 219-240
One of the most crucial problems by the 'Vehicle-Mover-Terrain' interaction lies in sufficiently exact identification of the friction and rolling parameters as well as in the subsequent interpretation of this information for on-board control systems. The simple analytical solutions are possible here in the case that a vehicle moves on the road or other anthropogenic surface. Otherwise the uncertainty of the motion environment complicates the problem. Especially this is true for unmanned autonomous vehicles and planetary rovers. Within the framework of the presented investigation the fuzzy method for handling the identification tasks is under discussion for the wheel-surface interaction by conditions with the different grade of uncertainty. Examples of fuzzy sets are considered for the physical characteristics of a bearing surface and vehicle dynamics parameters. The simulation results for vehicle control algorithms on the basis of the fuzzy derived information about the driving parameters are given in addition.
http://dx.doi.org/10.1504/IJVAS.2011.041386
Fuzzy methods in ground vehicle engineering : state-of-the-art and advanced applications. - In: Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011, ISBN 978-90-76019-31-4, (2011), S. 3008-3015
The paper discusses the evolution of fuzzy methods for core applications of ground vehicles and presents the results of several original works and conceptual solutions. The article introduces statistics of relevant research publications with special attention given to fuzzy control of brakes, suspension, vehicle stability, and energy management in hybrid and full electric ground vehicles. An analysis of nearly thirty-year bibliography dedicated to automotive fuzzy systems indicates steady trend to expansion of this research area. To illustrate implementation of fuzzy methods, the article presents the architecture of an integrated vehicle dynamics control system using parallel information channels from driving environment, vehicle dynamic parameters, and driver.
Multi-task integrated vehicle dynamics control. - In: Programme and proceedings, 2011, EAEC2011_C31, insges. 13 S.
An active implementation of mechatronic technologies and electronic drives leads to an essential increase of autonomy of sub-systems in modern and coming ground vehicles. On the one hand it makes possible efficient technologies of multi-task control. On the other hand the autonomy of vehicle sub-systems can call for internal conflicts of properties, for instance, between comfort and safety. From these positions the presented research discusses the following issues. 1) Multi-agent vehicle architecture: Analysis of connections between vehicle sub-systems and properties; introduction of vehicle structure composed from agents. 2) Multi-task strategy of vehicle dynamics control using objective functions: Search of a set of actuations to generate required yaw torque for vehicle stabilization taking into account estimated power demand and losses of energy during curvilinear motion of the vehicle. 3) Case study: Integrated control of handling, stability and performance of motion with different automotive sub-systems; Particular contribution of each subsystem under complex integrated control; Analysis of results obtained by computer simulation. The research outcomes show that an intelligent placing of priorities by the control on autonomous vehicle sub-systems allows achieving a certain simultaneous effect in performance and safety. The results of the presented research are oriented towards applications for electric vehicles, autonomous mobile machines, and vehicles with an intensive embedding of X-by-wire technologies.
Advancement of vehicle dynamics control with monitoring the tire rolling environment. - In: SAE International journal of passenger cars, ISSN 1946-4002, Bd. 3 (2010), 1, S. 199-216
One of the most important challenges for electronic stability control (ESC) systems is the identification and monitoring of tire rolling environment, especially actual tire-road friction parameters. The presented research considers an advanced variant of the ESC system deducing the mentioned factors based on intelligent methods as fuzzy sets. The paper includes: Overview of key issues in prototyping the algorithms of Electronic Stability Control. Case study for vehicle model. Procedures for monitoring of tire rolling environment: theoretical backgrounds, computing methods, fuzzy input and output variables, fuzzy inference systems, interface with ESC algorithm. Case study for ESC control algorithm. Examples of simulation using Hardware-in-the-Loop procedures. The proposed approach can be widely used for the next-generation of ESC devices having the close integration with Intelligent Transport Systems.
http://dx.doi.org/10.4271/2010-01-0108
Do drivers steer toward or away from lateral directional vibrations at the steering wheel?. - In: Proceedings of European Conference on Human Centred Design for Intelligent Transport Systems, ISBN 978-2-9531712-1-1, (2010), S. 227-236
A study was conducted to reveal whether drivers steer toward or away from vibro-tactile stimuli applied at either the left or the right half of the steering wheel. When instructed to react with a fixed mapping, steering toward the stimuli seems to be easier in an abstract environment with significantly faster reactions and fewer errors. However this effect is neutralized an tends to be inverted in a driving environment where steering away from the stimuli seems to be more logical.
Beeinflussung der Interpretation synthetischer Lenkradvibrationssignale durch Variation der Stimulusparameter. - In: Useware 2010, (2010), S. 49-58
Kinematic discrepancy minimization for AWD terrain vehicle dynamics control. - In: SAE Mobilus, 2010, 2010-01-1895, insges. 16 S.
Stability of motion, turnability, mobility and fuel consumption of all-wheel drive terrain vehicles strongly depends on engine power distribution among the front and rear driving axles and then between the left and right wheels of each axle. This paper considers kinematic discrepancy, which characterizes the difference of the theoretical velocities of the front and rear wheels, as the main factor that influences power distribution among the driving axles/wheels of vehicles with positively locked front and rear axles. The paper presents a new algorithm which enables minimization of the kinematic discrepancy factor for the improvement of AWD terrain vehicle dynamics while keeping up with minimal power losses for tire slip. Three control modes associated with gear ratio control of the front and rear driving axles are derived to provide the required change in kinematic discrepancy. Computer simulation results are presented for different scenarios of terrain and road conditions. The effectiveness of the proposed control algorithm was analytically proved by modeling the same vehicle with no kinematic discrepancy control.
https://doi.org/10.4271/2010-01-1895
Der Vollkatalysator vor dem Turbolader - effektive Abgasnachbehandlung vs. Fahrdynamik. - In: 5. [Fachtagung] Emission Control, (2010), insges. 22 S.
Moderne Dieselmotorenkonzepte mit variabler Turbinengeometrie zeichnen sich durch eine hohe spezifische Leistung und niedrigen Kraftstoffverbrauch aus. Der hohe Wirkungsgrad führt jedoch zu niedrigeren Abgastemperaturen. Dieser Effekt beeinflußt die Funktion der notwendigen Abgasnachbehandlungssysteme nachteilig. Im Hinblick auf eine sich weiter verschärfende Abgasgesetzgebung und der Entwicklungstendenz hin zu zweistufigen Aufladesystemen stellt die möglichst motornahe Positionierung des Oxidationskatalysators einen vielversprechenden Lösungsansatz dar. Im Rahmen eines Forschungsprojekts wurde ein Vorturbolader-Katalysator mit bis zu einem Liter Volumen für maximale Konvertierungsraten entwickelt.
Slip power loss and fuel consumption control in 4x4 terrain vehicle applications. - In: Proceedings, 2010, insges. 15 S.
4x4 terrain vehicle applications widely use positively locked power dividing units (PDU) in the transfer case. Such PDUs considerably improve vehicle mobility by keeping identical rotational velocities of the front and rear wheels and re-distributing the torque between the driving axles as terrain conditions require. The mentioned equality of the angular speeds leads to kinematic discrepancy in linear velocities of the driving axles when a vehicle undertakes turns. The paper presents an analytical method to evaluate this discrepancy and analytically demonstrates its influence on extra power losses on slippage of the front and rear tires and thus on extra fuel consumption. To avoid these extra power losses and fuel consumption, the paper presents a method for controlling the kinematic discrepancy by reducing it to zero values. This was done without negative impacts on vehicle dynamics. The theoretical propositions are illustrated by computer simulations of a 4x4 heavy-duty truck turning in terrain. A comparative analysis is presented with regard to the same truck but without kinematic discrepancy control. The results proved the proposed approach to managing the kinematic discrepancy in 4x4 vehicles with positive engagement of the driving axles to improve vehicle energy efficiency.
System fusion in off-road vehicle dynamics control. - In: Proceedings, 2010, insges. 14 S.
One of the most challenging problems in off-road vehicle dynamics control is connected with development of new generation of systems aimed at simultaneous optimization of performance, safety, and mobility. Progress in this area is closely associated with fusion of driveline, braking and steering control on the basis of intelligent architecture. The presented work contributes to this topic and discusses the following aspects.1) Multi-level architecture of integrated off-road vehicle control: Controlling systems and vehicle properties as intelligent agents, decision-making process.2) Fusion of control systems: Control philosophy of integrated electronic stability program, torque vectoring, and active front steering from viewpoint of vehicle performance and stability. 3) Simulation: Case studies for simultaneous operation of electronic stability program, torque vectoring and active front steering. The results presented in the paper can be used by development of vehicle dynamics control systems both for off-road mobile machines and for autonomous vehicles.