Q2. What are the future works mentioned in the paper "Tire/road friction coefficient estimation applied to road safety" ?
Following this work, the authors plan to validate the method embedded on a real vehicle, and to integrate the multi-model approach to estimate the maximum lateral friction coefficient.
Q3. What is the main objective of the first block?
The main objective of the first block is to provide the vehicle mass, the load transfer and vertical forces applied at the tire/road level, and the corrected lateral acceleration relative to vehicle roll, denoted ay .
Q4. Why does the friction coefficient for a wet road exceed the saturation limit?
Because of the extremely low friction, and the speed of 60km/h, the dynamics of interaction exceeds the saturation limit for the lateral forces.
Q5. What is the purpose of the estimation process?
The estimation process consists of two blocks, and its role is to estimate side slip angle, normal and lateral forces at each tire/road contact point, which provides the input of the process of estimating the maximum friction described in Section IV.
Q6. What is the lateral force at the center of gravity?
Where ax and ay are respectively the longitudinaland lateral accelerations, ψ̇ is the yaw rate, θ̇ is the roll rate, ∆i j (i represents the front(1) or the rear(2) and j represents the left(1) or the right (2)) is the suspension deflection, wi j is the wheel velocity, Fzi j and Fyi j are respectively the normal and lateral tire-road forces, αi j is the side slip angle at the center of gravity (cog).
Q7. What are the inputs of the simulator CALLAS?
The simulator CALLAS provide parameters of vehicle dynamics that constitute the inputs of the block “ Observer (Data)” in Figure 3, which are essentially: suspension deflections, longitudinal and lateral accelerations , yaw rate, wheel speeds and steering angle (inputs for their forces observers in Figure 2).
Q8. What is the lateral force of the simulated vehicle?
Hypothesis 2: If Hypothesis 1 is verified, the authors assume that at every time k of the trajectory, it is possible to calculate an error ei j = Fyi j −Fyi j where Fyi j is the lateral force calculated with the Dugoff model and Fyi j the lateral force estimated by the observer.
Q9. What is the lateral force of the vehicle?
Fy11 denotes the lateral force estimated by their forces observers with the parameters provided by CALLAS; Fydugo f f11 denotes the lateral force estimated by the Dugoff model for a given µmax , and e11 the error function.