Synchronization Control For Multi-Sensor In Rail Inspection

With the rapid development of the railway,trains have brought great convenience to the people for their travels.However,we also have to face an important issue that how to protect the passengers’safety and comfort during the travel.The tracks’geometry state and irregularity situation will determine the safety of the train,that’s to say,we need a fast and efficient testing equipment to achieve the rapid detection of the tracks’geometry state and irregularity condition,so that we can inspect and eliminate potential hazards to ensure the safety of trains.Most of our traditional detection are based on manual measurement,which is not only inefficient but also can be affected by workers’ subjective factors themselves.The imported rail inspection equipment is expensive and huge.It needs high demands for the operators and it’s inconvenient to use.Considering the situation of domestic and international rail inspection,we should design a miniaturized,intelligent rail inspection system,which will have high application value.Multi-sensor integration and synchronization control is one of the core technologies in rail inspection system, and it’s also the key problem needed to be solved in this thesis.This thesis analyzes the data interface and features of a variety of different sensors such as a two-dimensional laser scanner,wheel encoders,three-axis accelerometer and three-axis gyroscope, CCD cameras. On this basis, we focused on the multi-sensor synchronous control methods of the rail inspection system;Then we discuss the multi-sensor synchronization control circuit implementations of the rail inspection system and complete design of the synchronization control circuit board and power supply circuit board. We use GPS PPS pulse output and high stability warming quartz crystal to build the high precision basic time and complete data synchronization acquisition through active sync mode to control scanners and cameras and other sensors. We take time as the nexus to achieve the synchronization alignment of attitude information of triaxial accelerometer and three-axis gyroscope and the laser point cloud and image information of the laser scanner and the camera. This has provided high-precision original synchronous data for the subsequent fusion and registration of the multi-sensor data;Finally, we build a complete test platform and carry out a detailed analysis for synchronous controller designed in this thesis.The test results show that time synchronization accuracy of synchronous controller developed in this thesis can meet the needs of rail inspection system and it can achieve the synchronization control of multi-sensor including accelerometers, gyroscopes, laser scanners and cameras. It’s able to provide highly accurate original multi-sensor data for subsequent data processing. Also, it lays a foundation for the localization of rail inspection system.