Steady state dynamic analysis and testing of an FSAE vehicle

Abstract

The work proposes a method for the synthesis of chassis parameters for achieving specific steady state and transient characteristics of a vehicle. An approach that employs a set of static and dynamic tests coupled with vehicle dynamics simulation models is presented which provide a better insight into vehicle tuning and gaining insight into these dynamic test results. The testing procedures are divided into static and dynamic tests. Static tests focus on characterizing the vehicle's suspension and steering systems by employing a Kinematics and Compliance rig. These static tests are essential before conducting any dynamic test to make sure the dynamic tests cover the non-linearity caused due to these. The static test is followed by the dynamic tests along with MATLAB simulations to gain initial understanding of what to expect from these test procedures. A steady state test is carried out to compute the understeer gradient of the vehicle which in physical terms can be translated to how comfortable the vehicle is to drive over a range of lateral acceleration. The simulation involves the static test data which completes the metric estimation at both simulation level as well as from the raw data. This steady state test is followed by a transient test which employs tools from control theory to make it easier to analyze the vehicle and tune it for specific transient response times which are favorable to the driver. These dynamic test outputs can now be used for the synthesis of vehicle parameters. The parameter sensitivity of metrics from the simulations can be used to fine tune the vehicle during testing sessions in a more intuitive and effective manner.