Model-Based Design of Multi-Physics Automotive Systems

February 07, 2014 // By Sujit S. Phatak, DJ McCune, Hitachi Automotive Products Research Laboratory
This article explains the use of cyber-physical modeling to complement traditional physical prototyping.

Today's vehicles epitomize the concept of multi-physics systems. Design teams are bringing together software and electronics, along with airflow and environmental sensors, mechatronic, hydraulic and pneumatic subsystems, to create increasingly sophisticated automotive systems.

Traditionally, the automotive industry has made extensive use of “downstream” engineering. Design teams have followed the traditional “V-cycle”, which splits the engineering process into two phases — design and implementation followed by validation.

While design teams can benefit significantly from earlier validation of their concepts, the industry has historically favored physical prototyping as a means of validating the design, which requires a commitment to build a hardware prototype early in the project lifecycle.

This is often followed by a sequence of reworking, patching and more prototyping. Design teams pursue this cycle until the design appears to be bug-free. Unfortunately, such a downstream approach to engineering can lead to periods of prolonged patch fixing while engineers chase their tails and lose production cycles. If we cannot fix the design by patching, it may require a complete re-design. In the worst case, we may not discover the problem until the vehicle is in production, which can lead to disastrous product recalls.

Upfront Engineering

While simulation doesn’t remove the need for physical prototyping, it does considerably reduce the number of prototyping cycles that we need to go through during a project. By spending more time upfront with the design, we avoid many of the downstream problems.

Simulation enables us to learn more about the system and understand how it works. Because simulation models give us better visibility into the way our designs work conceptually, we can get rid of bugs — hopefully before we build them into the prototype. An additional benefit is the ability for new team members to get up to speed with the design by experimenting with the simulation, which doesn’t risk causing damage to (expensive) physical prototypes.

Cyber-Physical Systems

A model-based cyber-physical systems (CPSs) (Figure 1) development approach enables design

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