    Returns:
      A tuple with the 2x2 A matrix, and 2x1 B matrix
  
    Parameters in the vehicle model:
      cF: Tire stiffnes Front [N/rad]
      cR: Tire stiffnes Front [N/rad]
      aF: Distance from CG to front wheels [m]
      aR: Distance from CG to rear wheels [m]
      m: Mass [kg]
      j: Rotational inertia [kg m^2]
      sR: Steering ratio [-]
 
</s> remove     If the speed is too small we can't use the dynamic model (tire slip is undefined),
 </s> add     If the speed is too low we can't use the dynamic model (tire slip is undefined), </s> remove   Ax + Bu = 0 => x = A^{-1} B u
 </s> add   Ax + Bu = 0 => x = -A^{-1} B u </s> remove Dynamic bycicle model from "The Science of Vehicle Dynamics (2014), M. Guiggiani"
 </s> add Dynamic bicycle model from "The Science of Vehicle Dynamics (2014), M. Guiggiani"
    cF: Tire stiffness Front [N/rad]
    cR: Tire stiffness Front [N/rad]
    Returns:
      A tuple with the 2x2 A matrix, and 2x1 B matrix
  
    Parameters in the vehicle model:
    cF: Tire stiffness Front [N/rad]
    cR: Tire stiffness Front [N/rad]
    cF: Tire stiffness Front [N/rad]
    cR: Tire stiffness Front [N/rad]
      aF: Distance from CG to front wheels [m]
      aR: Distance from CG to rear wheels [m]
      m: Mass [kg]
      j: Rotational inertia [kg m^2]
      sR: Steering ratio [-]
keep keep keep keep replace replace keep keep keep keep keep
 Fxing some typos in vehicle_model.py comments (#20220) 
selfdrive/controls/lib/vehicle_model.py