Design Of CAN Network For Real-time Capability In In-wheel Motor Drive Electricvehicle

With the shortage of oil, coal and other energy, countries around the world havetaken solutions one by one. Electrical vehicles will be the inevitable trend in automobileindustry. As the development of electrical vehicles and electric motor technology,in-wheel motor drive electric vehicle with four wheels drove by four motorsindividually has become a promising direction. As in-wheel motor drive electric vehiclewheels drove separately, vehicle can take drive-by wire technology, abandon traditionalmechanical structure and decrease weight.As the change of people’s consumption concept and sense of worth, it demandsvehicle with safety, conformance, power, economy and environmental protection. Thenumber of electronic control equipment increases with the performances increasing.Every function system needs to coordinate each other. And automotive harness hasincreased multiply under the application of traditional communication method point topoint. The increase of harness not only adds the weight, but also increases themaintenance difficulty and decreases the operation reliability. With the application ofCAN bus, the vehicle harness decreases, data transmission speed and reliability are high,it is easier to complete the diagnostic function and software upgrade of ECU.On the basis of realization of electronic differential control function in in-wheelmotor vehicle, a CAN network is designed, network performance is analyzed andverified. As no special CAN application protocol is drafted for electric vehicle, the CANnetwork for electric vehicle is designed which includes analysis of topology structure,design of communication protocol and definition of message data field. With theanalysis of different network topology structure, the most appropriate one is selectedand designed. The analysis of CAN network performance includes brief introduction ofCANoe software, creation of database of simulating model, introduction of real-timeperformance evaluating parameters, analysis of network scheduling, analysis of networkcommunication delay and CAN bus load rate. In the chapter of CAN network nodessoftware and hardware designs, main chips and circuits are introduced briefly, programof sending and receiving messages are also designed and anti-interference methods areapplied to the network system. When performing the electronic differential control testin in-wheel motor drive electric vehicle, CAN network is applied among sensors and ECUs to realize the control of four-wheel steering which verifies the real-time,reliability and validity of CAN network system.The design of CAN protocol can provide a reference to draw up CAN protocolspecification for electric vehicle. And the CAN network designed for in-wheel motordrive electric vehicle has a good real-time, reliability and validity which ensure theachievement of electronic differential control.