Research On Measurement And Control System For Automotive Chassis Dynamometer

With the development of the technology, the structure of the automotive is improving. and people now pay more attention on the vehicles performance. Automobile is a complex system and its technology condition may become worse during use, especially with the increase of road haul and the extension of service time, so the automotive needs periodical detection. Automotive chassis dynamometer, testing equipment without disassembly, adopts technical of modern electrical measurement and computer to simulate all the driving resistance. So that the road test items can be tested indoor, and it will reduce the impact of outdoor environment. It can not only improve the testing environment but also increase the test precision.Firstly, this paper explains the aim and significance, also introduces the development history and previous achievements of the automotive chassis dynamometer, then, gives its structure and the principle of work. On the basis of contrasting the resistance of the car driving on road and on the chassis dynamometer, it puts forward the electric simulation model. The advantage is that the flywheels are omitted, so it amplifies the structure of chassis dynamometer and realize the continuous simulation of inertia. As to the hardware of system, the design of data acquisition circuit and signal processing circuit of the torque and rotation rate, enhances the gathering data accuracy, and assures the system testing precision. The realization and design of excitation control system is also presented in detail. In the way of communication, the design of the CAN and USB converse circuit not only realizes the communication between slave-computer and host-computer, but also breaks through the bottleneck of communication speed in the automotive chassis dynamometer. For the control strategy of the system, the controlling algorithm called integral separation PID is applied, achieves rotational speed, torque and excitation current double closed-loop control. As to the software of the system, the design idea and main flow charts are putted forward. The portability and flexibility is increased by the modular programming of this software. Finally, constructs the experiment table, and tests the system. The experimental result indicates that the system can satisfy the request of automobile performance teat.