The Communication Control And Application Development Based On OBD ?

With the rapid development of automobile industry and the dramatic falling price of the cost,nowadays car has gradually fitting into our daily lives.From regarding as a walking transport to considering as the tools we play with,now people have put forward the quality of the cars.At first,how to improve the level of car's power and comfort by spending lower is the primary problem for car-makers priority.However in the present automobile mechanical design has been so mature,it becomes more and more difficult to trigger a revolution just by demanding on the machine promotion.In the high level of technology,it seems to a particularly demanding. Thus, under the impact of the electronic information technology,the combination of the Cars' technology and the electronic information has formed naturally.Through generations of development of automotive electronics, now the car almost all have complex ECU system. But the more complex brings the more hemp vexed. In addition, as the index of private cars adds up, a large number of automobile exhaust emissions make the environmental problems gradually outstanding.In order to provide the corresponding data and fault information from the such complex system to maintenance men and the owner in a short period, and in order to manage the exhaust emission effectively, the auto makers began to add the OBD((OBD, On Board Diagnosis) self-diagnosis system to the cars.In recent years.the android system are applied to the mobile phones.Under the impact of the intelligent mobile phone industry, the various functions of mobile phones are more and more convenient which effect and service our daily life.Inspired by this kind of new mobile phone,the idea that using calls gets the data to control the cars arises at the historic moment.The main work of this graduation design is that accomplish the application development of combining the OBD system and the phones with Android system.The main contents of this design can be summarized as the design of hardware and software. Firstly analyses the main agreements such as ISO9141-2, ISO 14230-4 and ISO 15765-4 which are interacted with OBD diagnosis system, so as to find out the mechanism to receive and send and transform the proposal as machine language.Next design the hardware electric circuit road of OBD modules used STM32 as main control chip, the main design work of OBD module are as follows:USB circuit, data transceiver circuit of CAN, transceiver circuit of K line and circuit of power supply and so on. Depict the PCB after finishing the design of circuits and make it into board, then weld it to undertake the whole design of hardware. Thirdly, write the programs of software which is made up of two main sections, the programming of OBD module-driven and the communication of diagnosis system and Bluetooth, the design for the upper workstation software of Android:the UI interface, the Bluetooth communication program of Android mobile phone, the voice recognition program and so on. Finally, test the whole design through testing the communication of the individual protocols are successful or not and the connection of mobile phone and OBD module so as to get the information of the simulator. Voice recognition can be divided into cloud telephony and local voice, respectively test the recognition rate and analyze the merits and demerits. The field test has been done after the simulator test, which can verify the correctness of the OBD module design, whether the automobile data can be read into the mobile phone or not, and whether the automobile can be controlled simply by mobile phone.