The SAE EDA committee was established to create and promote standards for the development and use of electronic design automation practices and tools within the Ground Vehicle industry. There are four areas that the committee is dealing with, driven by automotive OEMs:

1. Model-based embedded systems engineering (MBESE).
2. Supply chain model exchange.
3. Data dictionary (standard component definitions).
4. General area of design and verification methodology, which has been assigned SAE document J-2748.

In the first area, MBESE has widespread acceptance of model-based engineering or model-based design for software development and several companies also model physical processes. The committee wants to link verification of both models together. As Smith pointed out, they have techniques for doing these things separately — the trick is doing them together. That is one of the areas the committee is looking at. Half of the effort is a design methodology problem and half is a tool problem.

The second area, supply chain model exchange, deals with improving the modeling process throughout the supply chain. Tool providers can help by developing modeling tools that people can use to simplify the process of creating models and characterizing them.

The third area, standard component definitions, is required to avoid different interpretations of terminology.

In the fourth area, design and verification methodology, the proposed J2748 VHDL-AMS statistical analysis packages standard is already in the approval cycle. The committee has approved the proposed draft and it is in the next step toward becoming a recommended practice. J2748 will add statistical modeling support into the VHDL-AMS language.

The SAE is certainly not the only organization developing standards to support improved system design that impact design tools.

The AUTOSAR (AUTomotive Open System ARchitecture) initiative (http://www.autosar.org/) was introduced at the VDI conference in Baden-Baden, Germany three years ago and has made significant progress. Its goal is to allow embedded software to be viewed as an interchangeable component within the automotive supply chain. Today, it has had a 2.0 release. Mentor Graphics is among the design tools suppliers who are members of the initiative. They also worked on the 2.0 release package. “From a vehicle standpoint, you are going to see adoption of AUTOSAR target packages in the 2007-2008 start of production time,” said Larry Anderson, transportations business development director, Mentor Graphics. One of the key benefits of AUTOSAR to OEMs is the ability to reuse software modules. Figure 3 shows the AUTOSAR architecture[2].

One of the historically complex and problematic areas of the vehicle is the wiring harness. Today, an average vehicle wiring harness consists of 800 wires, 2.5 km in length, and 1800 connectors^[1]. “In a complex luxury sedan you can have four to five kilometers of wiring,” said Mentor Graphics' Anderson. “Next to the engine, it is usually the second most expensive component.” Mentor Graphics tools have been used to help OEMs determine the optimum silicon-copper trade-offs. This can avoid surprises that can occur when consolidating functions into a single ECU. The adverse wiring impact could outweigh the savings from the silicon-level integration.

The wiring harness impacts the overall vehicle electrical and electronic systems. “As electronics have increased dramatically in cars, so have the power distribution and management issues,” said Paul Latiolais, senior marketing manager, Synopsys. “What happens is if you work with traditional methodologies you are going to miss this.” The increased control systems and components require a different design methodology for the engineers who routinely have dealt with wiring harness issues.

One of the problems that Synopsys has addressed is signal integrity analysis of wiring harness networks. With the vehicle's complex, distributed computing systems, the wires connecting these systems include twisted pairs, shielded wires, wire bundles, harnesses and more. One design tool aspect requires performing signal integrity on the data network to determine how much ringing is occurring.

Another critical harness area involves power distribution. With added complexity and increased power in the vehicle's generation and storage systems, there has been an increase in the amount of connector/terminal melting as well as failed splices. To address this, Synopsys has a line of harness verification tools. However, power is a specific problem that is being addressed by several design tools suppliers. Problems frequently occur from the use of extra power adapters. “They need to be able to do the analysis now, to be able to make sure that they can meet the power requirements, all the permutations of the power requirements, plus any additional optional things people provide and still meet their cost criteria,” said Synopsys' Smith. Traditional overdesign is not acceptable because OEMs cannot afford it. Figure 4 shows an approach that Volkswagen used in working with Synopsys to simulate and analyze the vehicle's power network^[3]. Synopsys' Saber Simulator and MATLAB/Simulink were used in the process.

Wiring harness verification includes the power distribution in the wire harness, in-vehicle networking, and signal integrity analysis for the data networking, as well as power network analysis for generation, storage and load analysis. The addition of hybrid technology adds high-voltage inverters instead of simple dc to the vehicle's wiring harness complexity. This requires electromagnetic compatibility (EMC) analysis in the modeling as well.