- Jul 17 2014
SEMA Vehicle Technology - Dynamics
SEMA is expanding its capabilities to help members in the area of vehicle dynamics of aftermarket-modified vehicles and the new FMVSS 126 regulation that goes into effect for all U.S. cars and trucks in model-year 2012, requiring all vehicles 10,000 pounds or less to include an electronic stability control (ESC) system as standard equipment? The original purpose and benefit of this program was to help members quickly and affordably evaluate the impact of their products on ESC systems, but it has now grown to provide evaluation and analysis of the overall vehicle dynamics performance of aftermarket modified vehicles. A combination of appropriate simulation and vehicle testing (facilitated by Link Engineering) can now be tailored to the specific needs of a SEMA member. Product evaluation and design capabilities that were once exclusive to OEMs and Tier One suppliers are now accessible to SEMA members that choose to use them.
ESC monitors vehicle motion. When loss of control is imminent, ESC strategically applies the brakes to help stabilize the vehicle. Similar requirements for the rest of the global community are contained in the United Nations Economic Commission for Europe 13H regulations. Compliance with Federal Motor Vehicle Safety Standards is normally the responsibility of vehicle manufacturers; however, SEMA has taken a proactive approach and developed a methodology and program to evaluate the ESC performance of aftermarket-modified vehicles. To actually test every vehicle configuration is cost prohibitive for OEMs and the aftermarket, so SEMA sought outside help from leading industry experts and companies in the area of vehicle dynamics simulation and testing to develop a “best practices” solution to offer member companies. It’s important to note that any modification to the engine, steering, brakes, suspension, wheels or tires may have an impact on ESC performance. A virtual test method was demonstrated at the SEMA Show last year, drawing on the controls-development experience of Advanced Controls Engineering Consultants LLC, the CarSim vehicle dynamics simulation produced by Mechanical Simulation Corporation and the hardware-in-the-loop (HIL) technologies of dSPACE GmbH.
A modified Ford F-150 supplied by Superlift Suspension Systems was used as the test vehicle. In the demonstration, a virtual model of the vehicle was created in CarSim and was connected to the ESC controller and brake system of the actual vehicle. The CarSim software provides not only a dynamic model of the pickup but also a virtual proving ground on which to conduct the tests. It also includes steering and throttle inputs that are required to execute the sine with dwell test maneuver. CarSim connects to the ESC controller on the vehicle through the dSPACE hardware. Throughout the test, CarSim sends vehicle dynamics information about wheel speeds, steering-wheel angle, yaw rates and lateral acceleration to the ESC controller. The ESC controller performs as if it is experiencing the maneuver in an actual vehicle and controls the application of the individual brakes on the vehicle. Pressure transducers installed at each of the truck’s brakes report the application pressure back to CarSim, which determines the brake forces applied at each wheel of the simulated vehicle and the subsequent dynamic response. Displays and readouts of the vehicle’s dynamic response on CarSim plots allow engineers to determine whether the vehicle meets the required performance. The ESC-HIL simulation does this at a fraction of the cost of an actual physical test. An ESC-HIL demonstration with expanded vehicle simulation capabilities will be set up in the SEMA Vehicle Technology Center at this year’s SEMA Show, where attendees can see the latest advanced vehicle technologies impacting the specialty-equipment and performance aftermarket industry today and in the immediate future.