In common with the on-highway vehicle community, the off-highway industry is experiencing a revolution. Previously dominated by mechanical engineering, off-highway vehicle development is now focused on electrical and electronic (EE) innovation to deliver improved efficiency, safety, and product differentiation.
This, in turn, creates new challenges, specifically those relating to complexity. Arguably, purely physical structures are relatively easy to study, especially with the ready availability of techniques such as 3-D rendering, animation, and finite element analysis. But developing a traction control system integrated into a complete vehicle involves domains as diverse as control algorithm design, power consumption assessment, and frictional response modeling.
Modern off-highway vehicles contain highly complex embedded software code running on multiple electronic control units delivered by various suppliers, connected by an electrical architecture that distributes thousands of digital and analog signals around the vehicle, and potentially available in a huge number of configurations.
Compounding the challenge, in a bid to reduce costly subsystems such as drivetrain control, navigation and communications are no longer discrete. Signals are shared, software components from several subsystems run on the same processor, and actuators accomplish several functions. This makes the task of EE systems integration, everything from ensuring correct and safe vehicle behavior to creating documentation for all configurations, extremely difficult. Cost overruns, schedule delays, and design errors are inevitable.
Some thought leaders have concluded that traditional development processes, typically partitioned into separate domains such as electrical engineering and software development, can no longer cope. Instead they posit that the application of formal systems engineering techniques is the only way to deal with today’s EE complexity.
Individuals understand the term “systems engineering” in somewhat different ways. But in fact systems engineering is a rather formal discipline backed by a large body of research. High-level characteristics include:
• A multidisciplinary approach, considering the problem as a whole.
• Early identification and documentation of requirements.
• A structured development process proceeding from concept to production to operation.
• Consideration of both business and technical dimensions with the goal of providing a quality product that meets users’ needs.
At a lower level the systems engineering approach is often represented as a “V diagram.” Data at a high level of abstraction is progressively decomposed and enriched to lower abstractions until buildable components (software blocks, electronic components, wire harnesses, etc., in the case of EE systems) become fully defined.
These components are then progressively integrated, with repeated verification steps, until the complete system is assembled. Crucially, transitions between abstractions are ideally automated via machine executable specifications (a process known as synthesis) with full traceability maintained, such as from requirement to component implementation.
There is now good evidence that systems engineering principles can indeed be highly successful. And synthesis between multiple abstractions is the standard way of designing complex electronic chips. Indeed, this would be impossible without such techniques.
This is why executives responsible for vehicle EE development are now seriously studying the systems engineering philosophy. It’s also why software tool vendors supplying this area are starting to support the systems engineering paradigm with concrete capabilities such as requirements integrations, design synthesis, and verification platforms.
Many believe that systems engineering principles are indeed the solution to EE complexity and that companies who fail to embrace this paradigm will fall behind, or worse. There is no doubt the supporting technologies will continue to improve.
That said, the biggest issue to manage may well be organizational change, not bits and bytes. This is because the skillsets and methodologies needed to really leverage systems engineering imply quite significant organizational change, which is always a challenging task.
Martin O'Brien, General Manager, Integrated Electrical Systems Division, Mentor Graphics, wrote this article for SAE Off-Highway Engineering.