Research And Development Of The Pavement Roughness Auto Detection System Based On Laser

The roughness of road surface is an important target in the road evaluation and aroad surface construction. The roughness of road surface is direct reflection of thecomfort of the travel vehicle, the road security and the road use life. The roughnessexamination of the road surface can provide the decision-maker with the importantinformation which enables the decision-maker to make the optimized decision for theroad surface maintenance, conservation and renovation and so on; On the other hand,the roughness examination of the road surface can accurately provide the informationof road surface construction quality and a objective quality evaluation target for theroad surface construction. At present, The main instruments of the roughnessexamination of road surface have a three-meter straightedge and the continued-typeroughness instrument and so on, which is difficult to reflect the jounce and fluctuationof the road surface of longer wavelength under a higher vehicle speed by the lengthand the speed limit, also with some problems such as the examination inefficiency,slow speed, the huge and unwieldy machinery configuration, the poor measuringaccuracy, the poor reproducibility.This disertation constructs an automatic roughness detection system platformwhich is composed of the laser sensor, the acceleration sensor, the rotary encoder, theAC4071 counting card, the CAN card, the high accuracy A/D transformation card, theindustrial control computer and so on, and designs the system functions, logicstructure, feed circuit, interface circuits and equipment installation according to theactual work environment of the detection vehicle. RC filter circuit is used to filter thesensor signal, then demarcate the filter signal, and fix on linear curve by regressionequations.Secondly, according to vehicle vibration theory, the road detection wave lengthrange and the sampling interval are analyzed, the international roughness index andthe bump integrator algorithm is introduced.Again, using rotary encoder and AC4071 counting Card to detect the speed anddistance of the test car; through interrupt programming to control the sampling frequency of the lower unit; In order to guarantee data exchange accurately, rapidly,real-time between PC and the lower unit, design of the CAN bus transmission.According to the CAN message frame format, developed a communication protocol,and given the communication flow chart; In order to facilitate the administrator tomanage the roughness data, has carried on the demand analysis, the concept structuraldesign as well as the logical organization design to roughness database, and hasdeveloped the roughness data management software.According to work serialnumbers may realize addition, deletion, revise function about the road section, theraise unit, roughness data and so on.Finally, has carried on the massive test experiment, and proceeded repeatabilityand correlation analysis on the measured data. The experimental result indicated, theroughness automatic detection system reasonable, is feasible, has the very goodpractical value.