Braking Simulation Test

The test simulates a pure braking event. Inputs are the c.g. height, the desired braking g load, and optionally aerodynamic download. Based on the c.g. height, the g load, and the vehicle weight, a pitch moment is applied to the chassis while corresponding ground plane longitudinal force is applied at each tire contact. Longitudinal force distribution amongst the four tires may be specified or can be proportional to the vertical load. The chassis is controlled in force control such that it finds a natural steady-state braking attitude. Chassis loads and displacements, as well as corresponding loads, displacements, and orientations at each of the four wheels are measured.

After running the braking simulation, the chassis motion is replayed through the rig without the ground plane forces present. This allows you to separate kinematics effects from compliance effects.

Here are some characteristics that are measured in a Braking Simulation Test:

  • Axle Steer
  • Steer Rate
  • Jacking Forces
  • Pitch Rate (per G)
  • Pitch Stiffness Total
  • Longitudinal Weight Transfer
  • Tire COP Migration
  • Tire Deflection Lateral
  • Pitch Rate (per Torque)
  • Tire Longitudinal & Vertical Forces
  • Dynamic Cross Weight
  • Friction / Hysteresis