Improved Design And Experimental Investigation Of Non-contact Road Roughness Tester

Road is dividied into hard surface and soft soil pavement,hard road roughness is the main vibration source in the running progress of a vehicle,it is significant to research vehicle ride performance and ride comfort for the driver,soft soil road roughness characterizates the index of the microscopic characteristics of tiny surface peaks and troughs,and it is important to study the effect of tire and soil coupling and effective roughness.So it is very necessary to design a measuring instrument which is highly effective and accurate to obtain the information of road roughness.The paper uses non-contact measurement method,improves the design about mechanical transmission structure and control and data acquisition system,finally,carries out application experiments.At first,this paper analyzes the problems existing in the first road roughness tester,according to the requirements of the test system,uses a fixed reference datum,and acquires surface elevation information by the laser displacement sensor.The paper puts forward improving scheme in mechanical structure and control and data acquisition system,and matches mechanical transmission mechanism and the motor through theoretical calculation.From the point of convenient dismounting and transportation,selecting suitable connection mode and platform support between the test bench and control box.Secondly,according to the improving scheme,drawing the three-dimensional model of the tester based on SolidWorks software.Combining with the selection of components,processing the improving road roughness tester.The single-chip microcomputer is the core of the peripheral circuit,the paper writes the program of two axis motor reversing,starting and stopping process by Keil software,and designs the program of control system about serial communication between MCU and PC by LabVIEW software,and PC control system sends a command to make MCU excuting instructions corresponding to the program,so as to achieve automated testing,improve work efficiency,and ensure the smooth running.Again,the core of the acquisition system is using Lab VIEW software to display and store road roughness,the paper acquires the output signal of laser displacement sensor by Nl data acquisition card.And according to the calibration experiment and acquisition program,the collected voltage signals are converted to the road surface elevation,which is displayed,pre processed and stored on the PC machine.Finally,dynamiely measuring the standard block to analysis and compare the accuracy of the two generation road roughness testers,and the road roughness tester was applied to measure the cement road surface.Building dynamics model of 1/2 vehicle about 5 free degrees by MATLAB/Simulink module,making the RMS of acceleration as the evaluation indicator of driver's comfort,and analysing the results of simulation and experiments measrured at 16.1 km/h,7.5km/h and 4.9km/h to verify the reliability of measurement data from the improving road roughness tester.Based on the above accuracy validation experiment,the tester is applied to the measurement of soil roughness before and after the rutting.In addition,using the tester to scan the wood surface,reflecting the processing quality of the wood surface roughness,so as to expand the application about the tester.