非对称双轨火箭橇动力学建模与仿真研究

目的 以高速非对称双轨火箭橇系统为研究对象，建立包含橇-轨相互作用的相关动力学模型，开展全轨范围内的动态特性数值模拟研究。方法 在明确火箭橇的组成和动力学过程基础上，对非对称双轨火箭橇进行受力分析，推导和建立非对称火箭橇-轨道耦合动力学模型，并对火箭橇进行自由模态分析。分析获得火箭橇气动力时程曲线、考虑火箭发动机质量损失的附加质量时程曲线，同时重构了轨道不平顺模型作为轨道激励。在此基础上，采用动力学软件分析火箭橇系统的动态特性。结果及结论 产品橇模态高于第二级推力橇，第二级推力橇模态高于火箭橇整体模态。火箭橇加速度随运行速度的增加而增大，竖向加速度大于横向加速度，火箭橇高速运行过程时的危险部位位于侧边翼上，有折断的风险。火箭橇竖向滑靴之间存在相位差，火箭橇竖向做俯仰运动，横向为往复摆动，竖向动力响应约为横向的1~2倍。

Dynamic Modeling and Numerical Simulation ofAsymmetric Double Orbit Rocket Sled

The work aims to take the high-speed asymmetric double orbit rocket sled system as the research object to establish a relevant dynamic model including the sledge-rail interaction and carry out numerical simulation on the dynamic characteristics within the whole orbit. Firstly, the composition and dynamic process of the rocket sled were clarified, and the force on the asymmetric double orbit rocket sled was analyzed to deduce and establish the coupling dynamic model of rocket sled and orbit. Secondly, the free mode of the rocket sled was analyzed, showing that the product sled mode was higher than the second stage thrust sled, and the second stage thrust sled mode was higher than the overall mode of the rocket sled. Finally, the aerodynamic time history curve of the rocket sled and the additional mass time history curve considering the mass loss of the rocket engine were obtained and theorbit irregularity model was reconstructedas the orbit excitation. On this basis, the dynamics software was used to analyze the dynamic characteristics of the rocket sled system. The acceleration of rocket sled increased with the increase of running speed and the vertical acceleration was greater than the lateral acceleration. The dangerous part of the rocket sled at high speed was on the side wing, where there was a risk of breaking. There was a phase difference between the vertical slippers of the rocket sled. The rocket sled was pitching vertically and swinging back and forth laterally, and the vertical dynamic response was about 1~2 times that of the lateral one.