Page - 88 - in Maximum Tire-Road Friction Coefficient Estimation

4 Sensitivity Analysis 0.4 0.8 1.2 0 10 20 30 40 50 60 70 80 90 100 0.4 0.8 1.2 0.4 0.8 1.2 0.4 0.8 1.2 0.4 0.8 1.2 0.4 0.8 1.2 µmax b a x = -1 -2 -3 -4 -5 -6 µmax µmax µmax µmax µmax v x w fl , w fr w rl , w rr Figure 4.17.: Normalised sensitivities for all state variables except vy and bωz, which are zero within this region, for selected acceleration data points in Region 2 (negative longitudinal excitation) for 100 % braking torque on the front axle available on a future vehicle CAN than vy due to its relevance for VDC, it is included in Table 4.2. Nevertheless, the influence ofvy andβ onµ max is low compared to that of the wheel speeds. In addition, these influences have to be estimated for series application, which may compromise the robustness of an estimation algorithm ofµmax. In contrast, wheel speed sensors are standard in vehicles equipped with anti-lock braking systems (ABS) or electronic stability control (ESC). Thus, from the state variables presented in Table 4.2, only the wheel rotational speedswiwere selected for the observation strategy in Section 5. 88