Research E/E architecture goes open source

March 10, 2015 // By Christoph Hammerschmidt
In today’s cars, up to 80 electronic control systems are dealing with tasks such as antilock braking, adaptive cruise control or simply opening and closing power windows. The number of such ECUs continues to climb, bringing the complexity of the vehicles to the limit. To counter this trend, researchers of the Munich Technical University (TUM) have developed a two-layer embedded IT approach that could significantly reduce the complexity. This Automotive Service Bus system is now available under an open source license.

The Automotive Service Bus has been developed within the scope of the Visio.M project - a project that aims at devising a very energy-efficient battery-electric small car with near-series features. A prototype of the vehicle has been introduced almost a year ago; now the development team unveiled details about its software architecture which has been developed from scratch. Much like a smartphone’s architecture it is structured in two layers - one layer contains all driving and safety-relevant functions while in the other one the comfort functions are located, along with the communication with the driver (HMI) and with the internet. As a protection measure against cyber attacks the two systems are running on separate platforms. A single central control unit manages all vital functions that connects via CAN bus to actuators and sensors. The HMI and the external communications functionality run on an web-enabled computer. Its basic principle builds on the Automotive Service Bus.

Fighting complexity: The Automotive Service Bus is an automotive E/E architecture that enables modifications and enhancements throughout the vehicle's service life without compromising the safety. For full resolution click here.

The Automotive Service Bus functions as a message channel. All components connected can transmit and receive messages across this channel. The safety and security of the system is guaranteed through the fact that all these components normally have only reading access; only in strictly defined exceptional cases the central control unit grants writing permission.

Basically there are three types of messages: Events contain information, such as the current speed or position. Instructions are enabling interactions between individual components like setting a target temperature for the air conditioning system. The third message type is preferences - these messages contain driver-specific data such as preferred music type or home address. There is a common grammar for all components and message types. Additional functions, or components, can added, much like apps in a smartphone. They also can be updated,