On-Board Diagnostics over Ethernet

Abstract: Modern vehicles are more electrical than mechanical. As the vehicle industry goes on, more mechanical parts are being replaced by electrical components, e.g. x-by-wire. Weight and production costs could be the major factors in this revolution. To ensure the safety and in time response (meeting request’s deadline), the connection between these components is of great importance. Trying to find a protocol and standard that fits the vehicle industry to connect all ECUs, sensors and actuators together is not an easy task, since we are dealing with a system that has got a diverse type of traffic. Safety on the one hand and cost on the other hand are pushing the manufacturers to find the best networking protocol. In this report I am going to investigate the possibility and the risk of implementing on-board diagnostics over Ethernet. UDS (unified diagnostic services) and DoIP (diagnostic communication over Internet protocol) are the protocols that are going to be studied. To be more precise, I will investigate the possibility and the risk of UDS and DoIP implementation. The reason is that with the increasing number of ECUs and volume of data (parameter setting, downloading software, etc.,), the already implemented protocols and standards are not able to answer the required bandwidth. The wide acceptance and high bandwidth of Ethernet on one hand and its low cost infrastructure on the other hand has made Ethernet a candidate for this purpose.  The feasibility of Ethernet for in-vehicle network has already been investigated as I will show in the review of previous works. There are a couple of works that shows by using a suitable protocol in data link layer, we can meet the real-time requirement of a process. By reviewing these previous works we will find out that using Ethernet for vehicle on-board diagnostics is feasible. After investigating risks and manufacturer’s requirements along with worldwide legislations for the vehicle industry I will develop a DoIP gateway according to ISO 13400 which is connected to a CAN bus from one side and to a test tool via Ethernet from another side (Fig.1). UDS and DoIP protocols are implemented on both test tool and DoIP gateway. The practical part of the work is a complementary step in risk investigation that will be analysed. Having Ethernet as a carrier allows us to make use of different protocols, based on different needs like bandwidth, latency and real-time characteristics. This fact allows the network to have multi-type data which is usually the case with in-vehicle network. That is, we can use Ethernet not only for on-board diagnostics but also for other in-vehicle domains, such as the chassis, infotainment and comfort. At the end I will propose two models that will help the designers in this domain.