Model-Based Design

In the software world, model-based design has appeared as the best way to meet cost, quality and time requirements.

A model is a set of equations, laws or rules describing a system behavior, more or less accurately according to the kind of phenomenon studied. Physical prototypes can be replaced by virtual model, adjusted to an experimental database to be as close as possible to reality and simulated to analyze system behavior in any case of scenario.

During conception, these models will also be useful to try new features (like choosing the motor type of a hybrid vehicle).

The Model Based Design approach saves time during the designing phase of onboard software by testing each feature when it is developed. From the drafting of the specifications, it is possible to evaluate the feasibility of the customer’s requirements. Each step of the development benefits from this methods thanks to quick prototyping and modular solutions for simulation (hardware in the loop software and model in the loop).

The Model Based design approach eases system sizing by showing performance limits in the early phases of development.

Keeping in the loop with MIL, SIL and HIL

Hardware in the loop (HIL), Software in the loop (SIL) and Model in the loop (MIL) solutions allow you to validate your developed solutions with simulations of real situations. Their use accelerates deisn and enhances quality mastery, while reducing the appeal to real prototypes and physical tests.

Here is a short description of an “in the loop” simulation solution, in chronological order:

• MIL: Model In the Loop. The whole system is modeled, so it’s possible to simulate a complete environment (vehicle for instance) in order to test control laws and correct mechanical, electronic or software mistakes before prototype manufacturing (functional validation).
• SIL: Software In the Loop. Unit tests are run on the code that will be implemented into a calculator to correct errors related to system functioning (code generation validation).
• HIL: Hardware In the Loop. Control laws are loaded onto a physical calculator connected to the simulation environment, and sometimes an actual mechanical part, so as to check equipment implementation of control, response time … (integration validation).