| With the continuously increasing requirements in the field of reconnaissance,airborne laser communication platforms with longer communication distances,faster speeds,clearer images,stronger anti-jamming capabilities and higher accuracy have become the requirements of the development of today’s society.At the same time,miniaturization and weight reduction of airborne platforms and optical terminals will be a major direction for future development and will have broad market prospects.The stability of the boresight of airborne laser communication is the basis and prerequisite for establishing a laser communication link.The reduction of the body’s own weight and load will inevitably make its platform characteristics change.When working,the wind resistance,friction disturbance,low-frequency disturbance and high-frequency vibration of the carrier,and vibration transmission of the photoelectric pod are all slightly different from large-weight and large-scale drones.In addition,while the optical terminal is miniaturized,the traditional complicated tracking system also faces a major challenge of simplified structure.In order to meet the special requirements of the light-and-small UAV airborne laser communication for the stability of the boresight and the control system,this paper first introduces the development overview and trends of the domestic and international airborne laser communication and boresight stable platforms.Taking the stabilization of the visual axis of the airborne platform as the ultimate goal,the following three aspects of research have mainly been completed.Firstly,the influencing factors of the light and small UAV platform are analyzed,and the measurement test is set to quantitatively analyze the vibration characteristics of the platform and compare with the vibration errors of some mainstream models.This experiment was designed and implemented on the stabilization controller foundation.Secondly,by using the embedded platform NVIDIA Jetson nano to accelerate GPU CUDA parallel computing,the centroid extraction algorithm is optimized.By shortening the centroid calculation time and thus the closed-loop control time,the closed-loop bandwidth of the control system is increased from the side.Finally,a discrete sliding mode control algorithm based on combined approach law is adopted,and an inverse tangent function is used to improve the combined approach law,So that it does not need to determine the specific approach law switching point in actual work,Improved ease of use and the introduction of discrete systems disturbance observer method,to further improve the robustness of the control system,And the algorithm was simulated and tested.On the basis of completing the above three aspects of research,a number of experiments were also conducted on the entire visual axis stabilization system,including system identification,control subsystem dynamic tracking experiment,and laser communication performanceexperiment.Experiments verify that the stability of the sight axis achieved by this system is about 160 μrad. |
