hood to sky
...Follow the track to the future.....by Sanguin.
Vehicle dynamics                                                                                                                                           language

   Vehicle dynamics: angles and accelerations ... and something more

This page is separate from the Vehicle Testing section because it is a particular kind of vehicle performance test that is not an elementary test or a simple measure of one only parameter but it is the measure of different parameters that have to be correlated each other in order to calculate suitable indicators to achieve the fingers of vehicle behaviour. 
Several publications and technical articles are available about this subject, with different approaches, from elementary to  complex and articulate , frequently  Math models are so complicate to be hard applying  to Testing  environment.  My personal  contact with the subject was when i had to distinguish the amount of tyre behaviour from the entire Vehicle performance. After freezing the test conditions (vehicle, vehicle setup, path, speed in the different sectors,..) i started to measure the three fundamental angles, 
Pitch, Roll e Yaw, and to calculate they related gradients (first and second) to achieve the angular speed and the angular acceleration and the accelerations on the  x,y,z axis, then i calculated the energy content by RMS; the result was fair but in some case it was inconsistent, thus i realized two things:- i had to correlate more variables to define "suitable fingers",- i had to take in account  the parameters that determine a certain behaviour (ie it is not enough to measure Roll angle, the best should be to normalize the angle value with lateral acceleration (measured or calculated by vehicle speed and steering angle, or both..)

Angles & Accelerations_1
Angles & Accelerations_2

Even if the work is not complete, currently several fingers are available, and for sure the Testing Methodology is strong, reliable and suitable for different  testing  areas: on road and off road, components/parts of the vehicle or entire vehicle.

Something Different 3D1
Something Different 3D2

All information combined together!

At last I would like to introduce a complementary (with the previous one) testing metodology / instrumentation that allows to records and analyse all kinds of information available while testing dynamically the vehicle: 

  • DATA from whatever sensor (Analog, Can Bus, Frequency,...) in order to measure, quantify , calculate and assess
  • VIDEOS coming from cameras in order to see and make easy the understanding of the previous measure (frequently we measure something but sometimes it is hard to realize the reason)
  • POSITION from GPS in order to  understand where a certain event occurs and what sector of the track is critical
All the three sources are perfectly synchronised on the time axis, the cursors allow to move the through the time but compared with a traditional data log here two more information are available, that is a powerful key for testing vehicles and components.

Short video to understand the  test condition
Demo for Tyres... Parts... and Vehicle