Design Of A Transmission Ratio Curve Test System For Recirculating-ball Variable Ratio Steering Gear

As one of the important parts of the car, the quality of car steering transmissioncharacteristics determines the overall vehicle handling performance. The transmissionratio characteristic is one of the important factors that influence the steeringperformance. Using the variable ratio steering gear can effectively relieve thecontradiction between "light" and "spirit", and improve the driving operation. Forfurther research on variable ratio steering gear, circulating ball type variable ratiosteering gear ratio curve test system was designed. Through the test variabletransmission ratio curve, this system can test cycle characteristics of ball type variableratio steering gear ratio, which can provide a basis for checking in the development ofthe variable ratio steering gear.In this paper, according to the steering gear transmission characteristic teststandard, the virtual instrument technology was adopted, and the transmission ratiocurve test system was developed. It mainly contains the following aspects:1. The requirement of the transmission ratio curve test system for therecirculating-ball variable ratio steering gear was analyzed.Through analyzing the transmission ratio curve test, the needs of the test systemin function and performance was proposed; the overall structure for the test systemwas designed by use of the virtual instrument technology and the test procedures weredeveloped.2. The key technology of the transmission ratio curve test system wasresearched.On the basis of the overall structure of the test system, the key hardware of thissystem was designed, including the function design of the test bench and the testfixture, selecting the key equipment and designing the signal conditioning circuit. Atthe same time, combining with the functional requirements of the testing system, theoverall structure of the system software was designed. And the program of the systemcontrol module, the curve test module, the man-machine interface and the datamanagement was designed.3. Test data of the transmission ratio curve test system was analyzed. The mathematic method of the variable transmission ratio curve fitting wasresearched. On the basis of test data point, the transmission ratio curve fitting anddisplay interface was realized by using the mixed programming of LabVIEW andMATLAB.4. The error and system calibration of the transmission ratio curve test systemwere analyzed.The test system of random error and system error was analyzed, the componentsof the test system error were deduced, and the error of software was compensated. Atthe same time, the preliminary calibrations of the calibration of the test system werecompleted.The paper provides theoretical basis for the design of transmissioncharacteristics test system for recirculating-ball variable ratio steering gear, which cansolve the problems encountered in testing the transmission characteristics of trialproduct during the period of product development. Moreover, it can providetheoretical basis for real vehicle test.