<div class="htmlview paragraph">The increasing adoption of Antilock Braking Systems (ABS) has focussed attention on the stopping distances which can be achieved with such systems. At the same time, the efforts to “harmonise” the European and American braking regulations have highlighted the importance of the wheel-lock sequence and its effect on stopping distances.</div> <div class="htmlview paragraph">This paper investigates the parameters which influence the stopping distance potential of passenger cars with and without antilock control, and describes two alternative methods of analyzing the stopping capability, viz. a computer calculation program and a graphical design procedure. Examples of both methods are presented to illustrate the influence of the tire-to-road adhesion, the brake-force distribution and the antilock control on the stopping capability of typical passenger cars. Finally, a simple summary diagram enables stopping distance comparisons to be understood correctly.</div>

<div class="section abstract"><div class="htmlview paragraph">Linked front and rear braking systems are difficult to implement properly on motorcycles due to the large changes in wheel loading under braking. At the braking limit, there is little to no load on the rear wheel and any brake torque could lock it, making the vehicle laterally unstable. Therefore, most motorcycles have independent controls for the front and rear brakes, requiring the rider to balance the brake force distribution. Electric motorcycles have the ability to utilize the drive motor to apply braking torque at the rear wheel. In this paper a control technique has been developed to link rear wheel braking torque to the front brake lever without risking rear tire lock. Thereby, it is also possible to recapture the energy from rear wheel braking. The control strategy has been tested on a transient pitch model, with rotating wheels and tire model data. It has been found that the control strategy provides significant reduction of stopping time and distance when compared to only using the front brake, while maintaining lateral stability of the motorcycle and not requiring any additional effort from the rider.</div></div>

Antilock Braking System (ABS) is very useful in advanced automobiles to avoid slip and lock up of wheel when brakes applied. It is automobile protection system, the regulator is provided to regulate the required torque to sustain optimal slip ration. The slip ration signifies in terms of automobile speed and wheel spin. It is an automated system that relays on principles of threshold braking and cadence braking which were experienced by skilled drivers with former generation braking system. It reaction time is so fast to makes easy steering for the driver. ABS usually deliver advanced vehicle control and reduce the stopping distance in greasy and dry surface, on the other hand on loose surface like pebbles or snow covered pavement, ABS can knowingly rise braking distance, even though still improving vehicle control.[1].The antilock Braking System was developed by Gabriel Voisin in 1929

Heavy goods vehicles exhibit poor braking performance in emergency situations when compared to other vehicles. Part of the problem is caused by sluggish pneumatic brake actuators, which limit the control bandwidth of their antilock braking systems. In addition, heuristic control algorithms are used that do not achieve the maximum braking force throughout the stop. In this article, a novel braking system is introduced for pneumatically braked heavy goods vehicles. The conventional brake actuators are improved by placing high-bandwidth, binary-actuated valves directly on the brake chambers. A made-for-purpose valve is described. It achieves a switching delay of 3–4 ms in tests, which is an order of magnitude faster than solenoids in conventional anti-lock braking systems. The heuristic braking control algorithms are replaced with a wheel slip regulator based on sliding mode control. The combined actuator and slip controller are shown to reduce stopping distances on smooth and rough, high friction ( μ = 0.9) surfaces by 10% and 27% respectively in hardware-in-the-loop tests compared with conventional ABS. On smooth and rough, low friction ( μ = 0.2) surfaces, stopping distances are reduced by 23% and 25%, respectively. Moreover, the overall air reservoir size required on a heavy goods vehicle is governed by its air usage during an anti-lock braking stop on a low friction, smooth surface. The 37% reduction in air usage observed in hardware-in-the-loop tests on this surface theref

Antilock braking systems (ABS) have been developed to reduce tendency of wheel lock and to improve vehicle control during sudden braking especially on slippery road surfaces. The objective of such control is to increase wheel tractive force in the desired direction while maintaining adequate vehicle stability and steerability and also reducing the vehicle stopping distance. In this paper, an optimized hybrid controller using a fuzzy system is proposed for antilock braking systems. The objective function is defined to maintain wheel slip to a desired level so that maximum wheel tractive force and maximum vehicle deceleration are obtained. All components of fuzzy system are optimized using a genetic algorithm and error based optimization technique. The error based global optimization approach is used for fast convergence near optimum point. Simulation results show fast convergence and good performance of the controller for different road conditions

Antilock braking systems (ABS) have held promise for reducing the incidence of accidents because they reduce stopping times on slippery surfaces and allow drivers to maintain steering control during emergency braking. Farmer et al. (Accident Anal. Prevent. 29 (1997) 745) provide evidence that antilock brakes are beneficial to nonoccupants: a set of 1992 model General Motors vehicles equipped with antilock brakes were involved in significantly fewer fatal crashes in which occupants of other vehicles, pedestrians, or bicyclists were killed. But, perversely, the risk of death for occupants of vehicles equipped with antilock brakes increased significantly after adoption. Farmer (Accident Anal. Prevent. 33 (2001) 361) updates the analysis for 1996- 1998 and finds a significant attenuation in the ABS anomaly. Researchers have put forward two hypotheses to explain this antilock brake anomaly: risk compensation and improper operation of antilock brake-equipped vehicles. We provide strong evidence for the improper operation hypothesis by showing that the antilock brake anomaly is confined largely to drinking drivers. Further, we show that the attenuation phenomenon occurs consistently after the first three to four years of vehicle service.

Quelques problèmes de commande et d'estimation liés aux systèmes d'antiblocage des roues Cette thèse aborde trois problèmes liés à l’ABS dans le cadre de la dynamique de la roue : l’estimation de la rigidité de freinage étendue (XBS) des pneus lors du freinage d’urgence, la commande de l’ABS basée sur l’estimation de l’XBS, et l’estimation de la vitesse et de l’accélération angulaires de la roue à partir des mesures provenant d’un codeur avec des imperfections. L’objectif général de ce travail est de développer des outils visant à améliorer la performance des systèmes de freinage, en utilisant des techniques adaptées de l'automatique non linéaire. La première partie de la thèse est consacrée à la construction d’un observateur adaptatif commuté pour l’XBS, c’est-à-dire un observateur adaptatif dont les gains d’estimation commutent entre deux valeurs possibles en fonction du signe de la sortie mesurée du système. La stabilité de l’observateur est analysée en utilisant des outils pour des systèmes commutés et en cascade, ainsi que des concepts tels qu’excitation permanente et transformations singulières d’échelle de temps. La deuxième partie de la thèse est dédiée à la conception d’une loi de commande pour l’ABS. L’objectif de contrôle est formulé en termes de l’XBS et une loi de commande hybride est conçue afin de faire en sorte que les trajectoires du système satisfassent les conditions requises pour l’estimation de l’XBS. La stabilité du contrôleur est analysée en utilisant l'application de Poincaré. La troisième partie de la thèse aborde la construction d’un algorithme pour estimer la vitesse et l’accélération angulaires de la roue et éliminer des perturbations qui sont introduites par les imperfections du codeur, et dont l’amplitude et la fréquence sont une fonction de la position, la vitesse, et l’accélération angulaires (réelles) de la roue. L’algorithme est basé sur la méthode connue comme « time-stamping algorithm », ainsi que sur des techniques de filtrage est d’estimation de paramètres. Des essais expérimentaux et des simulations numériques illustrent la performance des algorithmes d’estimation et de contrôle présentés dans cette thèse. Dans tous les cas nos résultats sont comparés par rapport à l’état de l’art.