Braking System

Collisions with other vehicles represent the biggest threat to riders of powered-two-wheeler (PTW), and while emergency braking is the evasive manoeuvre most frequently required in PTW riding, many riders fail to perform it adequately due to constraints on response time precipitated by failures of perception, cognition and control actions. Effective rider training methods are necessary for the development of braking proficiency in response to emergency situations. This study proposes a testing and training paradigm that exploits a closer similitude with the real-world scenario by maintaining the natural coupling of action (vehicle manoeuvring) and perception (higher order skill) that underlies any coordinated response to an emergency event. The aim of this study was to understand the behaviour of the riders in the execution of emergency braking coupled with visual perception of vehicle motion as a response to an imminent collision and determine parameters that can be used to identify differences in skill level. Participants performed emergency braking trials in a realistic and controlled scenario using a mock-up of an intersection conflict with a real car initiating a left turn manoeuvre across the path of a PTW approaching from the opposite direction (Left Turn Across Path/Opposite Directions). Analysis of the deceleration patterns recorded during 12 trials per participant revealed that performance of braking in response to an unpredicted moving hazard differs from that in a planned self-timed hard braking. In addition, our results indicate that PTW rider performance may be assessed in a reliable and objective way using the combination of vehicle kinematics and human performance measures. The study identified four categories of riders classified by their level skills. Finally, an important finding was the lack of correlation of both years of riding experience and self-assessed overall riding skill with an objective measure of emergency braking performance such as effective deceleration. The results of this study will support a new training approach and provide insights for future design of active safety systems.

— This work entails the design and analysis of a braking system based on FSAE application. Different Engineering software like SOLIDWORK and INVENTOR professionals, Mat lab and brake system calculator was utilized to determine the pedal ratio, master cylinders and caliper design, the number of rotors and their geometry. The guiding factors of the design process were maximum braking power, minimal weight and manageable temperatures while maintaining reliability. An approach drawn from Prof. Peter Wright concept was adopted. In this work, every progression of design was assessed and interpreted in details. Data acquired was also interpreted and related back to the assumptions used in the design analysis. The basic aim of this work is to achieve the required standards for brake design in FSAE and to scale through the technical inspection at the competition. For this to be actualized, the system must be able to lock up all the four wheels on pavement from acceleration run. Ergonomics and easy adjustability were also what was considered in this work. The project complied with all of the templates and envelopes required by the FSAE 2015 rules. The work serves as a guide to developing a high performance race car for the FSAE competition and will foster the ingenuity of designers by making the proposed indigenous car possible in view of the local content initiatives in Nigeria.

ABSTRACT
There are different ways of measuring a friction surface temperature. However, all known methods of measuring brake interface temperature, like contactless methods, such as optical and infrared methods, or direct temperature measurement using thermo-couples or different temperature-sensitive materials, allow measuring temperatures in fact only under laboratory test conditions.
In this work the real time friction surface temperature monitoring is based on the measurement of the temperature in the depth of the brake pad friction material. This indirect way of measuring of the friction surface temperature allows temperature sensor operation throughout the whole operating life of brake pads. As this way of temperature measuring depend on the depth of the brake lining, the LWH (Linear Wear Hypothesis) was used to enable temperature measurement compensation in relation to the depth of the friction material.
In this paper only first results of such an approach were presented, while further and more detailed work is foreseen in the near future.

KEYWORDS: Temperature Monitoring, Braking, Friction Surface, Measurement, Modelling

The tribological aspects concerning the behaviour of friction materials in the range of low and very low sliding speeds (0.2 – 200 mm/min) are essentially different of those in the high sliding speeds range. This paper aims to study the stick-slip phenomenon which occurs in the range of low and very low speeds. Typically, for the stick-slip phenomenon to occur, the static friction coefficient between the two contact surfaces of the friction materials must be larger than the kinetic friction coefficient. For disc brakes, the stick-slip phenomenon is mentioned in many specialized scientific papers. The phenomenon is manifested through self-induced vibrations. The experimental results were obtained on a dedicated testing machine where the parasite stick-slip motion is reduced through the use of bearings.

Effective operation of autonomous/intelligent braking within the frame of autonomous driving systems depends not only on application of advanced control systems (including both hardware and software), but also on superior behavior and characteristics of every component of the braking system. In particular, this applies to friction wheel brakes whose performance depend on many influencing factors, among which brake interface temperature is the most important, because its influence on friction variations is much higher than that of other three influencing factors – brake by itself (its kind, design and characteristics), in addition to brake sliding speed and brake control force/pressure. Therefore, it is always a particular challenge to knowing the actual brake interface temperature values under any given brake operation conditions. Measuring of the brake sliding surface temperature during brake pad life is a specific and very difficult task to perform due to variations in service conditions of brakes, wear appearance and presence of water, corrosion, and other immersive impacts, etc. Therefore, it seems that some kind of combination of measurement data with corresponding modeling approach might enable some kind of quasi " continuous monitoring " of brake interface temperature by its prediction. With this aim a number of passenger car disk brake samples tests were performed in the laboratory by means of a single-ended full-scale inertia dynamometer. Previously defined test program was applied composed of a number of different service modes which enable duplication of real service conditions being as close as possible. Brake temperature was measured during these tests by means of thermocouples placed at different locations in the depth of the brake pad, in addition to temperature sensor which was located " at the sliding surface itself " , i.e. 0,5 mm deep from the sliding surface in the friction pad. This specific individual temperature measurements serve only as control parameters necessary to assess quality of the model. Results of all other temperature measurements made inside the brake pad are used to design analytical relation between these temperature measurement values and those for the contact surface temperature measurements. Validation of such a mathematical model was indeed made by comparison of theoretical with the experimental results in order to enable experimental and analytical estimation of brake interface temperature to be combined so as to provide information on temperature values during any section or the entire service life of the brake pads. It may be demonstrated that the estimated interface temperature follows well the character of variation of the actual temperature at any measuring point, as well as the interface temperature. Estimated values of the brake interface temperature in any real time measurement sequence offer sufficiently high accuracy requested to be used in the prediction model, and thus in any potential application of it for management of braking process at the level of any individual brake application.