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Intelligent Distributed Controllers and Its Applications on Automotive Electronics
Published May 23, 2004 by Society of Automotive Engineers of Korea in South Korea
The increase of new features and complexity of automotive systems is becoming increasingly difficult to manage. New functionality requires new and additional actuators and associated electronics. The sheer number of electronic modules and wiring are being limited not by features or cost of the electronics but by the difficulties to assemble and test the complete system at vehicle assembly plants.
To solve these problems, the concepts "Design for Integration" and "Design for Assembly" have been introduced in automotive industry. Concept, design, development, tests and validation of subsystems such as seats, doors, headliners, cockpits, are usually performed by the Tier 1, which can then control all processes much better than the OEM itself. All subsystems are integrated at a supplier's facility, according to the required configuration(s).
Therefore, new architectures are required to support the addition of new features but also enable the vehicle assembly plants to easily assemble and test each subsystem. One such architecture is a distributed multiplex arrangement that reduces the number of wires while enabling flexibility and scalability. It is based on a main bus communication system (CAN) between the main modules and a secondary bus such as LIN bus for communication inside some subsystems. LIN bus allows the system to be highly scalable while achieving lower costs than traditional solutions. In order to do this, the electronic components play a major role: The advances in semiconductor design and manufacturing processes enable the integration, in the same device, of analog, digital and power components to enable true system-on-chip solutions.
The conventional electronic control unit has been separated into one mechatronic master unit and small electronic units (elecinlines) designed to work as intelligent distributed controllers. These electronic inlines have only some passives and one or two active components: the control device, and the power actuators. The control device integrates the microcontroller, the voltage regulator, the LIN bus transceiver, amplifiers, drivers and the appropriate I/Os. The power actuators are usually relays, but, more and more, solid state switching devices are also used. These electronic inline are designed to be "universal," being its specific functionality defined by a simple core software stored in the microcontroller, plus a common interface protocol.