I. INTRODUCTION
According to results published in mechanic, wear and tribology sciences, temperature seems to be a critical variable when describing the state of a brake disc [1]. In fact, the surface temperatures of the discs are closely connected to the braking efficiency. This last is implied in the control of the vehicle, so on the vehicle behavior. The connection between disc temperature and vehicle safety operates through the braking friction coefficient. This parameter is the ratio between the effective braking force (brake torque) and the braking force desired by the driver (control). Thus, a lack in the braking efficiency can appear when a disc reaches high temperatures. This phenomenon is known as “fading”. Nowadays, it seems necessary to be able to mount an active detection of such a lack of braking capacity. Indeed, mechanical actuation is softly replaced by electronic braking systems. As mechanical links become wires, drivers have no more physical feedback of what really happens on their vehicle (e.g. brake pedal oscillations when an overheating of the discs occurs). But, there are other direct consequences of the excessive disc temperatures. First, they are a source of premature wear of the brake pads. Secondly, they can cause strong damages on components nearby the discs. So, the safety and the security of the vehicles are really influenced by the temperature levels of the brake discs. Thus, overheating could lead to vehicle immobilization (interruption of the exploitation). The prevention of these kinds of failures has an economical impact.