基于惯性补偿的脉冲风洞测力天平瞬态研究

Transient simulation for dynamic output of force measuring balance in animpulse combustion wind tunnel based on inertia compensation

脉冲燃烧风洞中开展高超声速一体化飞行器测力试验时,天平输出结果无法达到平衡,为动态信号,因此需对其进行动态响应特性研究。根据单分量测力天平的结构和工作原理,将其简化为弹簧、阻尼和连续杆系统,根据Lagrange方程建立了测力天平的动力学模型;对测力天平动态特性进行了仿真研究,通过施加不同周期的正弦载荷和阶跃载荷,计算得到了天平输出规律,结果表明激励载荷频率远离测力天平固有频率时,以弹性输出均值作为测力结果可行,但引入惯性补偿不仅大幅提高了输出结果的准确度,而且输入输出间的瞬时偏差大大减小,可以满足瞬态测力要求。

Load signals detected with a force measuring balance are dynamic ones when the measuring force test was conducted on a hypersonic speed integrated aircraft model in an impulse combustion wind tunnel. It is necessary to study the dynamic response features of the force measurement balance. Firstly,based on the structure and working principle of the balance,it was simplified as a system of spring,damper and continuous rod. Then,the dynamic equation of the balance was deduced with Lagrange equation. Secondly,the dynamic performance of the balance was simulated.Through computation,the balance's output law was acquired under sine excitation loads with different frequencies and step load. Results showed that when the excitation load frequency is far from the balance's natural frequency,the elastic mean output of the balance is taken as the force measuring result; introducing inertia compensation not only improves the accuracy of the output result of the balance,but also makes the transient deviation between output and input drop significantly,the output result of the balance can meet the requirements of transient force measurement.