Race sanctioning bodies have begun to drastically limit the number of days available to race teams for track testing in order to contain costs. Due to the limited amount of track time available it has become increasingly difficult to explore and exploit all of the possible changes that can be made to the car in order to improve its performance. Thus seven post testing is becoming more widely used by race teams to optimize their suspensions before arriving at the racetrack.
A seven post rig, as the name implies, comprises seven actuators. Four actuators are used to simulate the road inputs, while the other three actuators are used to simulate downforce and inertial loadings. The rig at the ARC is capable of reproducing various waveforms, including the capability of simulating track inputs. This paper describes modal testing of the car, where the modes of interest are the rigid body modes of the car: heave, pitch and roll. Future work will be concerned with results based on track simulation testing.
This paper describes how a seven post rig is used to optimize the suspension of a racecar. A quarter car model as well as a seven degree of freedom model with sprung mass freedoms of heave, pitch and roll, and vertical freedom of each unsprung mass, will be developed. Simulation results from the models will be used to illustrate the principles involved when tuning the suspension of a racecar. The results of the simulation will be related to the real world by showing results obtained from an actual seven post test of a Champcar.