Complex networks

FlexRay Gateway Module for onboard vehicle networks

The automobile was primarily invented to provide a new means of locomotion. The inventors certainly achieved their goal, but beyond this there is still plenty of room for improvement – and there are a variety of new functions that could still be added. This is driven by the demand for cars to do more and more, as well as changing requirements and innovations. For instance, today’s technical developments center on safety – although many technological innovations are developed in response to the need to fulfill legal requirements such as environmental regulations.

Technological developments in the field of entertainment have provided plenty of new ways to provide passengers with innovative ideas. Then there are driver assistance systems. These go beyond previous passive and active safety systems to provide drivers with tangible support at the wheel. For example, a car can automatically detect potentially hazardous driving situations, putting it in an ideal position to react preemptively should things go wrong and allow the driver to steer out of trouble. Further support is provided to ease the burden on drivers in the form of navigation systems in heavy traffic and driver comfort systems. But to provide all these new on-board functions, a vehicle has to be fitted with a huge number of electronic control devices, linked together by ‘bus systems’ (data bus).

For more than a decade most car makers have done this with a controller area network, or CAN for short. The advantage with CANs is that they are particularly good at meeting the requirements of control systems in the drive chain and car body electronics.

Beyond CANs, vehicles now also include media oriented systems transport or MOST. MOST networks are used for infotainment solutions and telematics. For price-sensitive applications the most viable solution is a local interconnect network or LIN standard. As demands placed on systems grew (data speed, safety, availability) it became more and more necessary to complement these bus systems with another bus for data communication within the vehicle. The solution: a time-controlled bus system known as FlexRay which only went into serial production on the BMW X5 in recent months.

The number of functions built into vehicles has risen almost proportionally with the number of devices needed to control them, resulting in huge complexity. To manage this complexity, the system has to be partitioned for the entire vehicle. No systems on the market are currently capable of networking all components. To enable data exchange between subnetworks, media gateways are used in the form of gateway modules.

These gateways are either integrated into control devices or work on a stand-alone basis. Until now gateways have typically made it possible to form a cross-link between the commonly used bus systems such as CAN, LIN and MOST. As the FlexRay bus system will play a major role in many new vehicle networks, there will be growing calls for gateways that make it possible to link up with this time-controlled bus system.

The experts at the Steinbeis Transfer Center in Goppingen have been working on the development of hardware platforms for timecontrolled bus systems for a number of years and have now come up with a gateway module known as FlexXCon compact. This module is used for rapid prototyping when testing vehicles with pre-production prototypes and release sample parts. A number of months before control devices go into series production, vehicle developers already need platforms on which to test vehicle communications out on the streets. Through the integrated Freescale HCS 12-μ controller, the FlexXCon module can pass on the data in the bus system to be linked up like for like, although users can also use their own application software to filter or modify data. So developers have at their disposal a highly powerful gateway module opening up a number of essential avenues to communicate with FlexRay buses on the vehicle.

The developers at the transfer center have paid a great deal of attention to the module’s suitability to vehicles. So not only should it adhere to vehicle standard ISO 16750, it had to have a small housing. Once completed the entire module fitted into a housing no larger than 124 x 85 x 35mm. To develop existing and future vehicle networks, users in the automotive industry thus have at their disposal a highly innovative, powerful and strong gateway module for use in all types of vehicles, allowing them to link up directly with the new FlexRay technology.

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