Research On Indoor Navigation System Of UAV Based On Visual Inertial Odometr

UAVs are widely used in various fields due to their good maneuvering characteristics,and the premise of autonomous flight is a stable and reliable navigation system as support.In an unobstructed outdoor environment,UAV navigation mainly relies on the global positioning system.Once the satellite signal is lost or difficult to obtain such as indoors,the UAV needs other auxiliary or alternative methods to achieve accurate navigation.Therefore,this paper takes the UAV indoor navigation as the background,takes the rotor UAV as the object,based on the visual inertial odometry,focuses on the positioning and path planning in the UAV indoor navigation system,and conducts a feasibility analysis.The main research contents are as follows:In view of the lack of GPS signal in the process of indoor navigation of UAV,the solution of visual inertial odometry is introduced.The front-end uses ORB and IMU pre-integration to complete visual feature point extraction and inertial data constraints,and then completes the time axis alignment between data through joint initialization of sensors;the back-end uses visual-inertial tight coupling for data fusion to obtain UAV pose information.And the fusion error is processed based on nonlinear optimization to realize navigation and positioning.In view of the problems that the UAV indoor flight path planned by the traditional A~*algorithm is close to obstacles and sharp corners,an A~* path planning algorithm based on the improved artificial potential field method is proposed.After using the A~* algorithm to complete the preliminary path planning within the flight range,an artificial potential field is introduced to optimize the path breakpoints to keep the UAV flight path away from obstacles and avoid sharp corners.The improved content is verified under Matlab comparative simulation and Gazebo physical simulation respectively.The results show that the improved path planning algorithm can achieve the expected effect.Combined with the indoor navigation requirements of UAV,Pixhawk4 and its supporting hardware equipment are used to build a UAV flight experiment platform.The software architecture is designed based on PX4 firmware and ROS,and physical experiments are carried out to verify the UAV indoor navigation method based on multi-sensor fusion in the actual environment.Data analysis shows that the positioning deviation of the UAV indoors is maintained at ±0.1～0.2m,and the planned path is far away from obstacles and does not appear sharp corners.It can be seen that the navigation system proposed in this paper has feasibility and application value in UAV indoor positioning and path planning.