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Real Time Simulation Using Noncausal Physical Models

By Tom Egel, MathWorks


As automotive electronics become more complex and more distributed, hardware in-the-loop simulation is increasingly adopted for performing controller software/hardware integration testing as well as controller/controller integration testing. Having real-time capable models correlated to the physical hardware being controlled is key to successful implementation of hardware in-the-loop testing. Because models for hardware in-the-loop must be developed in a short amount of time and then stay in sync through design changes, a best practice is to obtain such models from the system-level model used for requirements analysis and design tradeoffs. While there has been significant progress made in recent years on real-time simulator technologies, including I/O accuracy, use of off-the-shelf hardware, and acceleration using parallel processing, the process by which a system-level simulation model is reused for hardware in-the-loop testing is not well understood. 

This paper examines options for developing a system-level simulation model. When limited to causal modeling techniques, the process of creating models is often cumbersome and time consuming. Many engineers find noncausal (or acausal) modeling methods to be much more intuitive. However, getting acausal models to run in real-time requires careful upfront planning and, when required, methodical reduction. Finally, the paper presents effective techniques for physical model development and reduction.

Copyright © 2009 by The MathWorks, Inc. Published by SAE International, with permission.

This paper was presented at SAE World Congress.

Read full paper.

Published 2009

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