Research And Design Of Measurement And Control System For Chassis Dynamometer Based On LabVIEW

With the development of automobile industry and the continuous progress of automobile technology and people’s attention to environmental protection,safety and energy saving,the requirements of human society for automobile are also higher and higher.The vehicle itself is a very complex system,in the development or use process,it needs to be tested to ensure that the vehicle meets the expected performance requirements and safety requirements.Chassis dynamometer is a kind of equipment that can test the performance of the vehicle while keeping the vehicle intact.It integrates modern electronic control technology and computer technology.It can simulate the resistance of the vehicle when driving on the road,reproduce the road driving conditions of the vehicle,transfer the test items on the road to the laboratory for test,and reduce the outdoor In order to improve the accuracy of the test.At present,the chassis dynamometer which is put into use in China generally does not have the function of road resistance simulation,or the simulation of resistance is hierarchical,and its operation is complex,energy consumption is high,and the accuracy is poor.In this paper,through the analysis of the structure and working principle of the chassis dynamometer,the test platform of the chassis dynamometer system is built in the form of loading motor in the middle.The structure of the chassis dynamometer is more compact,the overall size is reduced,and the floor area is reduced.Based on the detailed analysis of the force situation of the vehicle driving on the road,the AC motor is used as the loading device of resistance simulation,and the traditional flywheel group is replaced by electrical simulation resistance.The electrical simulation resistance model of chassis dynamometer is established.At the same time,the acquisition of various parameters used in the electrical simulation of road resistance by chassis dynamometer is studied Research.The application of electrical resistance simulation simplifies the mechanical structure of chassis dynamometer,and realizes stepless simulation of resistance,which improves the test accuracy and operation convenience to a certain extent.In the control system of chassis dynamometer,Siemens PLC is used as the control core to control the frequency converter,and the vector control frequency conversion speed regulation technology is used to adjust the speed of the loading motor of the power dynamometer,so as to meet the requirements of stepless simulation of load resistance.At the same time,through the analysis of the energy feedback characteristics of AC motor,the energy feedback circuit is established by equipping the inverter with an active front-end with rectification / feedback function to realizethe energy feedback utilization.Finally,the idea of modular programming is used to design the measurement and control software of chassis dynamometer by using LabVIEW software programming platform,which enhances the flexibility and portability of the program.In terms of communication,PLC uses analog control to realize the control of frequency converter;through the design of software and the communication protocol based on TCP / IP,the communication between LabVIEW and PLC based on Ethernet is realized,which greatly improves the communication speed.