Multiplexed solutions to integrate the onboard electronics in the city-bus vehicles
The electrical circuits and installations in buses and coaches are essential for their good working. Drive, braking, suspension, opening door, security and communication systems depend on the electrical system of the vehicle. The disproportionate length of cable (about 4 Km of cables and 100 Kg of weight in a conventional installation), with more of 2,000 connections per vehicle, generates great difficult and the point-to-point links are not an effective solution. The industrial communication networks or fieldbuses are a multiplexed solution for onboard electronics in the public transport buses and coaches. The authors are working in the design and implementation of new modules based on FPGAs (Field Programmable Gate Arrays) to integrate body and chassis functions in the multiplexed solutions from manufacturers.
Design and Application of SAE J1939 Communication Database in City-Bus Information Integrated Control System Development
With the increase of the number and the complexity of city-bus ECUs (Electronic Control Units), point-to-point link method in traditional city-bus has caused the problems of information exchange, reliability and maintenance. In this paper, we defined the conception of CBIICS (City-Bus Information Integrated Control System) and constructed CBIICS framework with high speed CAN bus and low speed CAN bus so as to share information between different ECUs. In order to provide consistent control and status data in V mode-based CBIICS development process, we designed SAE J1939 communication database to implement ECU, message and signal management and query. According to the electrical devices of an actual city-bus, we finally designed and implemented city-bus lamp control experiment system based on SAE J1939 protocol.
Implementing a Fieldbus Interface Using an FPGA
Fieldbuses are serial communication buses frequently used in industrial applications. There are a lot of different commercial solutions making difficult the compatibility between the equipment of different manufacturers. In this way to change an equipment implies to change the fieldbus too with the consequent economic losses. To avoid this problems this paper proposes the implementation of the fieldbus protocol in a reconfigurable device. Using reconfigurable devices it is possible to modify the protocol of a communication bus without changing its hardware support. Due to the diversity of commercial fieldbuses this work is centered on the implementation of a FPGA based interface for WorldFIP, one of the most popular fieldbuses.