Infinite response. While using it with discrete vehicle model.

Hello I have modeled a 4 dof vehicle and I wanted to use this block to generate forces acting upon the tires.

I have measured values of: Motor Torque, Steering angle on the front wheels, Vx,YawRate

My model estimates: Vx, Vy, YawRate.

If I'd like to model the tires using LuTs the model somewhat works, to improve the model performance I wanted to utilize this function block however It seems to be unstable and I quite can't figure out why.

Answer 1

[Sam Chak]

Hi @Sebastian

Assuming the physical modeling blocks were constructed correctly in Simulink, use knowledge of 4DOF vehicle dynamics and the combined-slip wheel model to identify the component in the mathematical model responsible for the instability. This component may be a linear term, , or a nonlinear term, , where k is the coefficient that affects the system’s stability.

Next, based on the stability analysis in your research, determine the stability threshold for the parameter k and adjust k accordingly to balance performance and stability while satisfying engineering constraints.

If you troubleshoot complex engineering problems like this one without applying engineering knowledge, then it will be much harder, often like searching for a needle in a haystack. Physics and engineering knowledge helps by narrowing the search, and suggesting likely failure modes, and providing reliable methods to isolate the causes.