Research On High-precision And High-stable Positioning Technology Of Emergency Rescue Vehicles

Active suspension control method based on the front terrain preview is currently recognized as an effective method to improve vehicle ride comfort and handling stability.Among them,the high-precision and high-stability positioning of the vehicle is a key fundamental issue in realizing the terrain construction in front of the vehicle and plays a vital role.In addition,with the development of connected vehicle technology with location sharing as the core,the realization of high-precision positioning of vehicles can further promote the development of intelligent transportation.Positioning technology is one of the core technologies of vehicle sensing technology,and it is the prerequisite for vehicle intelligence.This article relies on the national key research and development plan jointly completed by Jilin University and Yanshan University,"Research on Key Chassis and Suspension Technology for High-Mobility Emergency Rescue Vehicles(including Fire Fighting Vehicles)".In this paper,the high-precision,high-stability positioning of the vehicle is achieved through multi-sensor data fusion.The simulation and real vehicle are used to verify the accuracy and stability of the positioning system.The thesis mainly completes the following aspects:1.This paper studies the existing localization technology at home and abroad,and proposes a vehicle positioning system solution based on multi-sensor data fusion.This article completes the sensor selection based on the system scheme,designs the hardware electrical connection diagram,designs the multi-sensor space-time synchronization scheme,and completes the construction of the system hardware platform.2.In order to improve the real-time performance and stability of the system,this paper proposes to use the GPS / IMU combination to build the system front-end odometer.This paper first completes the kinematics modeling of the three-axis vehicle,and derives the kinematics prediction equations based on IMU and the kinematics observation equations based on GPS.The status update is completed by the error state Kalman filter.In order to verify the accuracy and stability of the front-end odometer model,Matlab Simulink is used to simulate the model and KITTI data is used to verify the model's stability.3.In order to improve the accuracy of the positioning system,this paper proposes the use of lidar to build a system back-end optimization model.This paper first analyzes the lidar positioning error,and proposes an external parameter calibration tool and motion distortion compensation algorithm.In order to improve the efficiency of point cloud storage and search,this paper proposes a point cloud storage scheme based on a local elevation map based on GridMap and a global point cloud map based on OctoMap.In order to improve the speed and accuracy of point cloud matching,feature points are extracted for the global map and local map respectively,and the constraint equations for point cloud matching are constructed.Finally,the model is solved numerically using the Gauss-Newton iterative algorithm.4.The outdoor positioning system software is designed and verified by experiments.Relevant algorithms of positioning system are realized by program.This article tests the outdoor positioning and navigation system through two methods: simulation and physical vehicle experiment.The simulator of the emergency rescue vehicle was constructed by V-Rep,and the simulation verification of the system was completed.Finally,the accuracy and stability of the positioning system are verified on an actual hardware platform.Experimental results show that the outdoor positioning system designed in this paper can meet the needs of emergency rescue vehicles to achieve suspension regulation based on the front terrain of the vehicle.