A real-time simulation mandates that the virtual model delivers a response/solution output at specific time increments in the same or less time than the physical system. This way, the state of the virtual system is always synchronized with the physical components to provide an accurate testing environment.
For this reason, real-time compliant vehicle dynamics models for HiL and DiL integration have traditionally involved a low number of Degrees of Freedom (DOF), typically around 20. Such models are typically used to characterize the behavior of the body via lookup tables. While these Reduced Order Models (ROMs) are a valid approach for some applications, compromising on the number of DOFs is no longer a requirement for real-time computation.
Readily available high-performance computing and advances in engineering simulation techniques have now made higher fidelity real-time simulations possible, providing more valuable insights. Real-time simulations now provide an opportunity to connect physical components and virtual models in Hardware in the Loop (HiL) and Driver in the Loop (DiL) automotive test environments.
For example, MSC Software has designed Adams Real-Time to preserve the topology and parametrics of the MBD-modelled system in real-time applications. This makes it possible to maintain elements such as hardpoints, joints, springs, dampers, and bushings and make modifications without the need to calibrate a new ROM for every change. As such, the model can capture higher frequency characteristics in the system responses, and different configurations can be introduced and explored with a shorter turnaround time. Adopting a one tool, one model approach for both real time and non-real time applications eliminates error-prone model translations between different tools. This approach also makes it possible to tune and optimize systems very efficiently and has the potential to remove weeks from a typical vehicle development program.