CAN data buses are already used in several control circuits. The basic principle of CAN is that instead of a separate wire for each type of data, two wires are generally used. These wires exchange data on engine speed, fuel consumption, throttle position, engine intervention and switching processes.
The principle of CAN operation is based on the fact that each control device transmits its data to the network to which all other control devices are connected. If any device registers data that is important for its operation, then this data is taken into account by other devices.
However, due to the fact that a large amount of data from the electronic systems connected to a single network in a car must be transmitted reliably and in real time, Audi intends to abandon the ineffective CAN bus system in the near future. Instead of CAN, it is proposed to use a data bus system built using Time Triggered Architecture (TTA) technology - a synchronized optical or electronic bus system for systems that control the operation of the transmission and chassis.
In the models currently being produced, various controllers are installed to control the chassis: the electronic stability control system ESP, the electronic differential lock EDS, the traction control ASR and the air suspension. If it is possible to combine the individual systems so that they interact in real time, this will allow distributed control. To do this, the data recipient must know in advance the moment of receipt of the information, in addition, all systems must be synchronized in time. In TTA, all this is ensured by a specifically defined timeout. TTA technology allows the development, use and maintenance of fault-tolerant systems built on the principle of redundancy. This technology uses principles that have proven themselves in aviation.
CAN structure
The CAN system consists of the following components:
- CAN controller. The controller receives the data to be transmitted from the computing device, which is part of the control device. The controller performs primary data processing and transmits it to the CAN transceiver. In addition, the controller receives data from the transceiver, processes it and transmits it to the control device's CU.
- CAN transceiver. The transceiver transmits and receives data. It converts the data received from the CAN controller into electrical signals and transmits them to the data bus.
- Bus Termination: A resistance that prevents transmitted data from being reflected back and distorting the original information.
- Bus lines. Bidirectional lines CAN-Low and CAN-' High are used for data transmission.