Publié : 14 septembre 2015
Sean Carlson, Sr. Applications Engineer, dSPACE Inc.
With the increasing complexity of electronics in automotive and aerospace applications, the electronic control units are increasing dependent on overall vehicle and environment information available from other controllers. This information is shared through various communication networks. CAN, LIN, ARINC 429 and other traditional bus technologies. With the growing number of sensors and distributed controls, these communication busses are in need of serious improvement to keep up with the demand.
In automotive, this bus communication has often been done with a mix of busses and protocols like CAN, LIN, LVDS, and FlexRay. In aerospace, popular avionics data busses are ARINC 429 and MIL-STD-1553. In both of these industries, the prevalent busses are generally older and may not have the bandwidth necessary for modern systems. This is particularly evident with the development of Advanced Driver Assistance Systems (ADAS) and complex infotainment systems in modern automobiles, and more electrified aircrafts in aerospace.
As a result, industries are looking towards the potential use of Ethernet technology to address some of these demands and it is beginning to be used in some of the modern vehicle networks.
Ethernet offers a standard, cost-effective, high-speed technology to network devices like sensors and ECUs. The Ethernet standard defines the physical and data-link layers of a network. The higher-level functions of a network are commonly implemented by the TCP and UDP protocols.
TCP is a “connection-oriented” protocol which offers high reliability in exchange for some overhead and less speed. TCP uses a client/server model of requests and responses to ensure that data is received, as expected. For example, if a message was not received or the data was not as expected, it can be re-transmitted.
On the other hand, UDP is a simpler protocol with less overhead that does not guarantee the message is delivered. In some cases, particularly with real-time systems, UDP is desirable because the simpler send & receive mechanism can result in higher data rates and lower latencies.
Modern automobiles may contain ADAS systems comprising of multiple cameras and advanced sensors like radar and Lidar. These devices often use Ethernet because they produce a large amount of data that must be sent to ECUs for processing.
Ethernet is also important in the development of Vehicle-to-Everything (V2X) technologies. For example, wireless communication between vehicles and infrastructure may use the familiar WiFi technology.
Ethernet also plays a role in measurement, calibration, and flashing of ECUs. These operations are often carried out with XCP, a standardized protocol for these operations that can be used over several transport mediums.
CAN is commonly used for this (XCP on CAN) but it does not offer high data rates. By utilizing Ethernet as the transport layer, many more variables can be measured and calibrated, and flashing of large ECU applications is much faster.
A possible ECU topology utilizing Ethernet to connect major vehicle subsystems, as well as high data rate devices within subsystems
Within the aerospace realm, ARINC 664 is a communication standard based on Ethernet and designed as a next-generation data network. Many existing aircraft use ARINC 429, which operates in one direction only.
A large ARINC 429 network, which is common on modern aircrafts, requires a significant number of transmit and receive channels, each connected by two wires. This results in a complex and heavy wiring harness. Additionally, ARINC 429 messages are 32 bits and the maximum data rate is only 100 kilobits per second, which is not much data for modern systems.
By using a data network based on Ethernet, a large ARINC 664 network can be connected via switches. Through the use of 100 megabit per second full-duplex transceivers and Ethernet frames up to 1518 bytes in size, a large amount of data can be exchanged with ARINC 664. ARINC 664 also has features desirable for aircraft networks like redundancy and determinism (via a traffic control mechanism called the Bandwidth Allocation Gap).
In order to support customers’ increasing use of Ethernet in automotive and aerospace applications, dSPACE offers a number of hardware and software tools.
Newer hardware platforms like the DS1007 and MicroLabBox include built-in gigabit Ethernet adapters. Modular platforms can be extended with Ethernet capabilities. Software support is available with various products and solution blocksets, which have similar ease-of-use to other dSPACE bus blocksets. Support for aerospace busses like ARINC 664 is offered as a combined solution of a third-party hardware and a dSPACE blockset for model integration.
It is clear that the demands of modern automotive and aerospace electronics require better data networks. The use of Ethernet-based networks offers high data rates through standard, cost-effective components. dSPACE offers a number of hardware and software products to facilitate the development of ECUs utilizing Ethernet.
|NEW: RTI Ethernet Blockset||RTI Ethernet (UDP) Blockset||Ethernet Configuration Package|
|Supported dSPACE platforms||
|Additionally required hardware||–||
|Purpose||Connects DS1007 and MicroLabBox to Ethernet devices. Supports bypassing applications with DS1007-based real-time systems.||Connects dSPACE real-time systems to Ethernet devices and networks. Suitable for bypassing.||Supports automotive middleware SOME/IP. Connects DS1006-based dSPACE real-time systems to Ethernet devices and networks.|
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