基于惯性补偿的三分量测力天平瞬态特性的研究

Transient Characteristics Research of Three-Component Force Measurement Balance Based on Inertia Compensation

关键词:  测力天平  动力学建模  惯性补偿  瞬态分析

Key words:  Force balance  Dynamics modeling  Inertia compensation  Transient analysis

摘要:

高超声速一体化试验模型在脉冲燃烧风洞中进行测力试验时，模型振动导致天平无法准确测量模型所受到的气动力载荷。为研究脉冲风洞瞬态测力问题，采用了以下方法:根据测力天平的结构特点建立了动力学方程；对其进行了虚拟标定和模态分析；对测力天平进行了瞬态分析并对输出结果进行了惯性补偿。结果表明，单分量阶跃载荷加载时，补偿后输出结果超调量大大下降，振动衰减时间缩短，俯仰力矩会对轴向力输出产生干扰，且三分量阶跃载荷加载时，干扰降低，各分量的超调量分别为162.6N，574.4N和38N·m；单分量正弦加载时，加载分量上输入输出基本一致，俯仰力矩对轴向力的干扰作用仍然存在，3分量正弦载荷加载时，输入输出结果具有相同的周期特性，俯仰力矩结果与输入结果一致，轴向和法向输入输出间存在一定偏差，3分量的超调量分别为24.1N，375.7N和70.8N·m。

Abstract:

The oscillation of the test model will greatly affect the measurement of aerodynamic load or moment， when the hypersonic integrated model tested in the impulse combustion wind tunnel. The following methods were used to solve the issue of transient force measurement. Firstly， the dynamic equation of the force balance was deduced according to its structural characteristic. Secondly， the virtual static calibration and modal analysis to this force balance were conducted. Thirdly， the transient analysis was conducted and the inertia compensation method was used. The result proved that the amplitudes of vibration reduced significantly and the attenuation time shortened sharply after the inertia compensation. And the axial output was disturbed by the pitching moment while the disturbance would be lowered when 3-component load and moment were applied. The amplitudes of each component were 162.6N， 574.4N， and 38N·m， respectively. The output of the force balance under single component sine load or moment was strictly accord with the input after the inertia compensation， although the axial disturbance under the pitching moment was still existed. Furthermore， the output and input embraced the same frequency and the transient output of the pitching moment was accord with the input， however， the axial and normal output loads had some difference with input when the balance under the action of 3-component sine load and moment. The maximums exceed the amplitudes of each component were 24.1N， 375.7N， and 70.8N·m， respectively.