“Configuration complexity of electrical systems for commercial trucks is one of the major problems confronting OEMs like Daimler Trucks,” said Nick Smith, Business Development Director, Integrated Electrical Systems Division for Mentor Graphics.
Daimler Trucks, a leading commercial truck manufacturer comprising multiple brands and design sites, has deployed Mentor’s CHS electrical design software at Mercedes-Benz in Germany, recently expanding its use to mainline design, according to Smith. CHS is also used at Mitsubishi Fuso Truck and Bus in Japan, a major subsidiary of Daimler Trucks. Mentor reports that both groups operate complete electrical and wire-harness design flows using tools available in CHS, such as Capital Logic and Capital HarnessXC.
“While OEMs will ship individual trucks tailored for particular customers, potential configurations of just the electrical systems can range into the millions. Managing this complexity while reducing weight and giveaways is essential to reducing overall cost,” said Smith.
To tame this complexity, CHS provides electrical engineers a common design environment, enabling them to reuse design data and consolidate component usage. The CHS integrated application suite is targeted for large organizations such as Daimler Trucks with its multiple subsidiaries. It offers capabilities such as embedded data management for vehicle configuration management, workflow control, and design comparisons.
The modular construction of CHS allows the two divisions to employ different design philosophies but still share data and resources. Mercedes opted to use the CHS interactive flow as a natural transition from its existing design process, while Mitsubishi implemented the CHS generative flow.
“Interactive and generative flows are radically different approaches to electrical design methodologies,” explained Smith. “With interactive, individual engineers develop the wiring design by literally clicking and pointing on a computer screen. In generative flow, the computer generates the wiring based on rules the engineers provide it.”
Capital Integrator is the key enabler in the CHS suite for generative flow. One benefit of generative flow, according to Smith, is controlling complexity by managing the superset of all possible configurations allowed by configuration logic. “By 'allowed' I mean, for instance, a specific truck can be left-hand drive or right-hand drive, but not both. That is a configuration rule that a design engineer can input into CHS,” he said.
Rather than designing the electrical system, the engineer designs the rules that ensure requirements compliance, such as homologation. Electrical design rules, connectivity logic between devices, and mechanical constraints provided by MCAD round out the basic inputs. “Capital Integrator acts on these four inputs to create a wiring design,” Smith said.
When using generative flow, the skill required of the engineer changes—from designing the wiring to designing the rules that create the wiring. Raising the level of design abstraction is essential to managing the complexity of modern vehicles. An organization making the transition from interactive design to a generative design philosophy must take into account this changing skill set of the individual engineer.
There is organizational impact as well. What CHS offers is a tool that spans both worlds, perhaps easing the transition into the rule-based, generative process. Smith sees it as the future: “We are pretty convinced that in a few years, no car or truck electrical distribution system will be designed by anything but a rules-based, generative process.”