Bumping Analysis And Measurement Instrument Development For Laser Based Pavement Detection System

With the development of highway, road maintenance management has become an important task in the highway construction in our country. The pavement roughness, rut and cracking are important indexes to reflect the pavement quality, which will affect the lifespan of the pavement, vehicles energy assumption, transportation efficiency and the transportation safety. So it is crucial to detect and recognize them automatically and accurately before repairing them. But, the Vehicle bumping during the detection of multi-functional vehicles due to the roughness of the road will cause the camera bumping, laser attitude changing, and thus bring the errors to the measurement of roughness, rut and cracking.For these problems, the measurement error caused by vehicle bumping and the characteristics of the signal about vehicle bumping are firstly analyzed, and then the measurement scheme of combination gesture about GPS/SIMU based on MEMS inertia device is proposed. Simulation experimental analyses and results show that this scheme is correct and feasible. Under the guidance of this scheme, the vehicle bumping information measurement device has been developed successfully. This device not only measure the vehicle bumping information in real-time, and to provide data support for avoiding measurement error, but also can provide vehicle attitude, speed, location and other information through post -data processing.The main research works in this dissertation are as follows:(1)From the perspective of mechanism that vehicle bumping effects on the road detection, the paper analyses the impact of car attitude change on the accuracy of road detection, and gives the mathematical relationship as the basis of subsequent error compensation. Then the paper proposes the accuracy target of vehicle attitude measurement based on the relationship.(2)The paper establishes mathematical model of the vehicle bumping, derives mathematical formula of the line acceleration and pitch angular velocity in the simplified model under the conditions of the vehicle bumping, and analyzes the characteristics of the vehicle bumping signal, then takes this formula as a basis for design method and selecting devices.(3)According to the characteristics of the vehicle bumping signal, the paper determines GPS / SIMU combination of attitude measurement programs and verifies the feasibility of the scheme through theoretical analysis and experimental results(4)Based on DSP processor, the paper designs accelerometers, gyroscopes, GPS and optical encoder (DMI) signal acquisition circuit, and completes the data collection, storage and communication with the host computer program.