For the first time, commercial vehicle makers can simulate vehicle dynamics with sufficient realism to develop control systems, handling and safety systems with a human driver in a virtual environment, thanks to software from rFpro of the UK. Previously, simulators were too slow to respond to driver input due to a combination of hardware and software limitations, which restricted their use to human factors studies or ergonomics development.
One of the first commercial vehicle projects to benefit from the use of rFpro technology was a study for Hyundai, carried out by a team from Applus IDIADA, the state-of-the-art vehicle testing and development organisation in Spain.
rFpro’s software allowed IDIADA to link Hyundai’s CarSim model with realistic graphics and a human driver to evaluate the benefits of using a simulator for chassis development. Once sufficiently developed using a workstation, the application was transferred to the eight degrees-of-freedom Sim IV platform at The Swedish National Road and Transport Research Institute (VTI), which has been at the forefront of simulator development for over 40 years.
“In the space of 10 days we were able to evaluate around 25 different vehicle configurations using three professional drivers,” explained Guido Tosolin, Applus IDIADA’s product manager, Chassis Development and Vehicle Dynamics Simulation. “More importantly, because of the high fidelity visual cueing using rFpro software, driver immersion was very convincing which led to good correlation between their subjective ratings and the objective data.”
During the study, drivers correctly interpreted the direction and magnitude of various changes to kinematics, springs, dampers and anti-roll bars. An additional benefit was derived from the high volume of data produced, according to Tosolin. “For the first time, we have generated so much data that we are able to use statistical methods effectively to interpret the results,” he said.
The IDIADA project is believed to be the first major application of a driving simulator to commercial vehicle chassis dynamics and required a suitable cabin arrangement and driving position to be effective. It also used rFpro’s own virtual Vehicle Dynamics Proving Ground which allows subjective and objective testing to take place just as it is done in real world track testing.
“Our software is based on closing the loop as quickly as possible by providing very high bandwidth video and audio feeds to the driver and high bandwidth road surface detail to the vehicle model. This provides the realism necessary to achieve good correlation between driver perceptions and objective vehicle changes,” explained rFpro’s technical director, Chris Hoyle. “The quality of major design decisions in the early stages of a new vehicle programme can be greatly improved by supplementing engineering data with subjective ‘feel’ and in many areas human input is an essential ingredient. Using a driving simulator allows vehicle manufacturers to pull forward this activity, even though no physical prototypes exist.”
Specialist software company rFpro works in partnership with motion platform producers, such as MTS and Ansible Motion, to deliver a turn-key system, if required, and the software can wrap around vehicle models from all the popular modelling environments, including Dymola, SIMPACK, CarSim, CarMaker, Simulink, AVL-VSM, LMS Virtual.Lab Motion, VI-Grade and C/C++. Global supplier, MTS Systems Corporation, recently selected rFpro software for its new VDS (vehicle driving simulator) in order to provide an off-the-shelf driving simulator with cutting-edge dynamic performance.