Simulators are essential part of the development process of vehicles and their advanced functionalities. The combination of virtual simulator and Hardware-in-the-loop technology accelerates the integration and functional validation of ECUs and mechanical components.
The aim of this research is to investigate the benefits that can arise from the coupling of a steering Hardware-in-the-loop simulator and an advanced multi-contact tire model, as opposed to the conventional single-contact tire model.
On-track tests were executed to collect data necessary for tire modelling using an experimental vehicle equipped with wheel force transducer, to measure force and moments acting on tire contact patch. The steering wheel was instrumented with a torque sensor, while tie-rod axial forces were quantified using loadcells.
The same test set has been replicated using the Hardware-in-the-loop simulator using both the single-contact and multi-contact tire model. The simulation apparatus is composed of a static simulator equipped with a removable steering robot. The static simulator integrates the entire steering system from the steering column up to tie rods, where dynamic forces are applied by two torque motors.
The first part of the activity focuses on validation of the steering Hardware-in-the-loop test bench, investigating its capability to accurately reproduces the steering system operating condition. During this phase the steering robot is demanded to replicate the steering angle time history while the two test bench motors were required to contemporarily replicates tie-rod forces. The comparison between track and simulator data highlights the test bench capability to closely reproduce steering system inputs, confirming its value as validation tool.
Subsequently the collected data and driver feedback are examined
to individuate the advantages introduced by the multi-contact tire model during common and limit handling manoeuvres.
This model proves to enhance the steering feel providing accurate tie-rod forces to be applied to the steering system as function of the wheel slip angle, enhancing the driver perception of vehicle stability. The multi-contact tire model also demonstrates to enhance the effect of asphalt micro and macro roughness in tie-rod forces calculation, avoiding unrealistic spikes which negatively affect steering feel.
The result of this study demonstrate that advanced multi-contact tire model can be a valuable addition to hardware-in-the-loop simulator significantly improve steering feel perception.