Research on deployment process of gravitational airdrop UAV

无人机重力投放展开过程研究

School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China

Received: 18 June 2021

Abstract

Due to the space limitation of the launching platform, the wings of the space-based gravity delivery UAV need to be folded before launching. In the process of wing folding and launching, the dynamics model of UAV will show the characteristics of multiple rigid bodies and multiple degrees of freedom, and the aerodynamic characteristics of UAV are also quite different from that of cruise stage, so the traditional aircraft dynamics modeling method is no longer applicable. In this paper, the multibody dynamics model of gravitational airdrop UAV is first built based on the Lagrange equation, and then according to the aerodynamic change on unmanned aerial vehicle in deploying process, the angle between the wing and the fuselage is introduced as a new variable, the UAV launch phase nonlinear aerodynamic model is established, and through comparison with software calculation results the reliability of the aerodynamic model is verified. Based on the aerodynamic model and dynamics model, the dynamic response of UAV deployment process is simulated, and the influence of UAV deployment process on UAV subsequent pulling stage under the same control instructions is compared, and the dynamics and kinematics characteristics of gravity launch are studied and explored. Finally, the simulation results are compared with the experimental data, indicating that the multi-body dynamic model established in this paper can accurately describe the dynamic response of UAV in the launching stage and the subsequent modification stage, which can provide reference for the technical personnel engaged in the design, test and use of related models.

摘要

空基重力投放类无人机由于发射平台的空间限制, 投放前需要将机翼进行收拢。在机翼收拢投放的过程中, 无人机的动力学模型会呈现多刚体、多自由度特点, 无人机的气动特性相对于巡航阶段也有较大差距, 传统的飞行器动力学建模方法不再适用。建立了基于拉格朗日方程的空基重力投放无人机多体动力学模型, 针对无人机展开过程的气动力变化, 引入机翼与机身之间夹角为新变量, 建立了无人机展开阶段的非线性气动模型, 并通过与软件计算结果的对比验证了气动模型的可靠性。基于所得气动模型及动力学模型, 对无人机展开过程的动力学响应进行仿真, 并对比了无人机在相同控制指令下展开过程对无人机后续拉起阶段的影响, 对重力投放的动力学和运动学特性进行了研究与探索。将仿真结果与试验数据进行对比, 说明所建立的多体动力学模型能够准确描述无人机在投放展开及后续改出阶段的动态响应, 可为从事相关型号的设计、试验和使用的技术人员提供参考。