Automatic Brake Control for Trucks - What Good is It?

Dynamics of the Automobile Related to Driver Control

The objective of this study was to define those brake characteristics, within the space bounded by the relationship between brake pedal force and vehicle deceleration, which lead to acceptable driver-vehicle performance. A driver-vehicle braking test was performed in which the deceleration/pedal force ratio, the pedal displacement, the surface-tire friction, and driver characteristics (age, weight) were systematically varied in order to determine the influence of these variables upon minimum stopping distance and other performance variables. The tests that were performed on a low coefficient of friction surface showed that high values of deceleration/pedal force gain result in large number of wheel lockups and lower mean deceleration in bringing the vehicle to a stop, compared to intermediate or low deceleration/pedal force gain levels. Tests conducted on intermediate and high coefficient of friction surfaces showed that high and intermediate deceleration/pedal force gains produced greater mean decelerations and greater frequencies of wheel lockups than lower gain systems. The frequency of loss of lateral control was significantly greater with the high deceleration/pedal force gain brakes on all surfaces than with lower gains. There were minor benefits of 2.5 inch pedal displacement compared to zero inches. Potential brake failures and their effects upon pedal force requirements were analyzed. The implications of the findings for a vehicle braking standard were shown in terms of deceleration/pedal force gain and pedal force.

Brake force requirement study: driver - vehicle braking performance as a function of brake system design variables

This paper is concerned with the realization of semi-autonomous vehicle arrangements as the natural transition towards fully automated traffic In particular, we are interested in road trains or platoons, which involve a group of vehicles at close following distances This is known to reduce fuel -- or energy -- consumption due to reduced aerodynamic forces acting on them Currently, available techniques and technologies allow for inter-vehicle distances close to 5 meters with suboptimal fuel/energy savings To obtain the most savings from a platoon formation (with even less consumption for the lead vehicle), it has been shown that the inter-vehicle distance needs to be reduced to 25 meters or less making braking maneuvers even more dangerous In this paper, we present the design and analysis of a brake-by-wire system for the above case, whose operation is characterized by the law of the weakest That is, the system automatically adapts braking forces at different platoon members -- taking vehicles' load condition, etc into account -- to equalize that of the weakest one, ie, the one braking at the slowest rate in the platoon We present simulation results based on an automotive hardware-in-the-loop (HiL) setup with realistic car models Our experiments shows that the proposed system is safe, enabling for collision-free emergency braking at intervehicle distances of 25 meters and, hence, paving the way for highly efficient platoons

Braking in Close Following Platoons: The Law of the Weakest

Over the last 20 years there has been an exponential rise in the number of reports in the area of Tire-Road Skid Resistance. In a recent publication*, the authors surveyed the major findings and conclusions on this subject up to 1970. The present paper is a summary of that publication: it is designed to assist one in quickly becoming acquainted with the significant findings and landmark publications on the many different aspects of Tire-Road Skid Resistance research.

R. D. Lister

Papers

Retention of directional control when braking