The Design Of Vehicle Bearing Pavement Roughness Measuring System

Pavement roughness is an important technical index for road condition evaluation. The conventional roughness measuring devices usually include three-meter straight edge [1] and 8 wheels measure device and vibration gauge. As those devices need traffic regulation and not so accury reading. It is impossible for traditional devices completing so large amount of measuring work through out the road network. it is good chance for developing high speed and high accuracy measuring device with non-contactiong measuring technology.A laser-projection based road roughness measuring strategy is introduced in this thesis. It briefly works as follows. The laser emitter, the angle sensor, the acceleration sensor and the image sensor are all installed in the vehicle. First, the structural laser beam from the laser emitter is projected onto the road surface and a picture of the point of projection on the road surface is taken; secondly, this image, together with the data collected by these three sensors, are processes via image-processing technologies and geometric transformations so that the road surface profile curve (RSPC) is computed; thirdly, the road surface roughness is obtained.The laser-based profile meter, consisting of a laser emitter, a distance sensor and an Initial Measurement Unit, provides a new solution as a vehicle bearing measuring device that is capable of measuring the roughness when the vehicle is at about 100km/h. This is safer and more convenient. One key advantage of the proposed method is that instead of multiple-point road profile sampling, every picture taken provides a single RSPC which reduces measurement complexity and costs.The hardware system of the integrated measurement system is based on ARM7 microprocessors. Its software interface is developed by Visual C++ on Windows 2000 operating system. This methodology is able to process the collected data quickly, accessible under a variety of circumstances.