The information below was gathered from the 2018 Simcenter Conference - Americas that took place October 15-17 in Detroit, Michigan.
Author: Jesper Slattengren, Technical Fellow
That HEEDS is useful for optimizing wheel suspensions for regular vehicles, specifically in the off-road domain is well known and can greatly improve the ride comfort. Tasked by DARPA to develop an extreme mobility vehicle capable to traverse 95% of all land terrain, Pratt& Miller invented a novel suspension concept with over 6 feet wheel travel. This concept consists of two suspension modules in series, the upper is fully controlled and is responsible for driver and passenger comfort as well as the extreme mobility; the lower suspension is semi-active and has the main purpose of improving tire-road contact to increase road holding and handling. To develop this extremely complex system, Pratt & Miller turned to industry standard tools for the hardware and software development. ADAMS was used for the vehicle hardware,MATLAB/Simulink was used to model the hydraulic systems and controllers.HEEDS/MDO was used to tie the systems together and optimize hardware selection such as springs and hydraulic components as well as the controller parameters for the fully active high travel upper suspension and the low travel semi-active suspension. A total of around 100 parameters were included in the optimization that covered 7 different drive events to map the response of the vehicle to both handling, durability, mobility and ride events.