MacPherson Strut Kinematic Modelling

The MacPherson strut suspension is one of the most common front suspension types for road vehicles. Often this is due to it's packaging benefits, especially in vehicles with transversely mounted internal combustion engines. Understanding the fundamental geometry of the MacPherson strut suspension is important for creating new or designing modifications for such suspension systems. Traditionally this involves creating expensive bespoke prototype components to create a physical assembly and understand the system. A much more cost effective solution is to simulate the system to get an understanding of the design before any physical components are created. This can reduce the number of iterations of physical prototypes that need to be made or even eliminate them completely.

Quarter Car Model



The video above demonstrates Lamerton Simulation Ltd's quarter car kinematic model of a standard MacPherson strut suspension. Of modular construction and with just 13 degrees of freedom the model provides sufficient accuracy for basic kinematic analysis. Kinematic curves can be produced, for example camber and steer angle variation are plotted below against vertical wheel travel. These can be produced as well as standard geometric measures like King Pin Inclination (KPI), Caster Angle, Scrub Radius and Mechanical Trail. All can be calculated for various conditions.


Pic 2
Pic 2

Interested in getting a simulation for your suspension system?
Contact us by email at: info@lamertonsimulation.com

Standard Simulation Inputs

For a standard simulation the requirements are predominantly global locations in space (often referred to as hard points) for the following points:

  • Top Mount
  • Lower Control Arm(A-arm) Front and Rear mounts to Chassis
  • Lower Ball Joint
  • Track(Tie) Rod joint centres connecting to the steering rack and knuckle(upright)
  • Wheel Geometric Centre (or wheel centre outside face plus rim/tyre width)
Additionally Static Toe and Camber settings are required for accurate kinematic curves

Standard Simulation Outputs

  • Kingpin Inclination
  • Caster Angle
  • 3d image of kinematic assembly
  • Plot of kinematic Steer (variation with vertical wheel travel)
  • Plot of kinematic Camber (variation with vertical wheel travel)
Interested in getting a simulation for your suspension system?
Contact us by email at: info@lamertonsimulation.com

Who is this model suitable for?

This model is suitable for anyone looking to understand a MacPherson strut suspension system on a tight budget (e.g. low volume manufacturers, motorsport engineers, modders, students and automotive enthusiasts). This is significantly cheaper than the physical equivalent that can cost many thousands of pounds.

Want to run this model yourself?

This model is compatible with the OpenModelica simulation environment, contact us for further details.

And there's more...

This is just the tip of the iceberg in terms of the types of analysis that can be performed with this model, don't hesitate to contact us with any questions that you have. We are also developing equivalent models for other suspension types: double wishbone, RevoKnuckle, Super Strut as well as half car models with even more kinematic ability.