Multipost Rig

Saving time and development costs is of paramount concern when setting up the suspension of any vehicle, and because of this, Multimatic Engineering offers a vehicle evaluation and setup service.

With the help of a multi post servo-hydraulic test rig fitted with simulated aerodynamic downforce, Multimatic's engineers can assist users in quickly evaluating and understanding vehicles. A range of problems (such as suspension installation flexibility, friction level, non-linearity chassis torsional flexibility) can be measured and a good basic suspension setup can be achieved, setting a vehicle in an ideal starting point for final track optimization. The test techniques, which can often be completed in one day, give an insight into a range of vehicle parameters that would normally take a significant amount of track-testing effort to achieve.

Testing the Ford Mustang FR500CT at Multimatic Engineering's North America facility.	The control room includes a meeting area with overhead projecter for direct display of results, as well as control interface.
Multimatic Engineering’s test facility in Europe

Users can take advantage of the Dynamic Suspensions technique using test rigs at Multimatic Engineering's' UK headquarters or in Canada. Alternatively, complete multi post rigs can be supplied as can retrofit measurement/analysis systems for existing rigs.

The suspension of a road vehicle is normally set by subjective assessment of its behavior when it is being driven over known road surfaces. This process is expensive and time consuming and the quality of the result depends upon the experience and sensitivity of test drivers. Multimatic Engineering uses a multi post hydraulic test rig, a capable and flexible measurement system as well as analytical tools to supplement track tests. The combination of the two techniques reduces the cost and time required to develop a vehicle and also supplements qualitative assessment with quantitative performance measures. It has been shown consistently to yield improved overall performance for a broad spectrum of applications, ranging from rally cars to Formula One race cars.

A multi post test rig is used to excite an unrestrained vehicle through its tires in order to determine some of the dynamic characteristics of the vehicle, its suspension and its tires. Inputs are controlled accurately and are repeatable. This feature enables the effect of small changes to the vehicle and its suspension to be quantified with precision.

Information that can be extracted from measurements recorded includes:

• Estimated values for the sprung and unsprung masses, sprung mass centre of gravity and sprung mass pitch inertia
• Equivalent linear values for the vertical spring stiffness and damper coefficients
• Equivalent linear values for the vertical components of tire stiffness
• Natural frequency and damping ratio of the heave and roll mode
• The level of coupling between the heave and pitch modes
• Estimated tire dynamic stiffness
• Estimated damper force V's position and/or velocity
• Suspension friction level
• Suspension installation stiffness

4 Post Test Rig Specifications

Transducers can be supplied by Multimatic Engineering, or users' suspension position transducers can be used.