多体复杂系统力学载荷识别方法
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摘要
力学环境研究和试验条件制定需要获知船(星)箭组合体在上升段过程中经历的复杂的力学环境条件,然而目前没有针对发动机的推力脉动、跨声速抖振等外力函数的直接测量方法。针对该问题,文章提出了一种应用载荷识别方法反演运载火箭和卫星组合体在发射段力学载荷条件的新方法。运用Duhamel积分和模态叠加法,以二次多项式作为基函数,推导建立了多自由度振动系统动态载荷识别数学模型,并通过算例完成了与精细积分法的比较。结果表明新方法具有较好的抗干扰能力和很高的识别精度,且无误差积累问题存在,通过提高采样频率,减小计算步长,可获得更精确的识别结果,为工程应用提供技术支撑。
The identification of the complicated mechanical loads in the ascent stage of the launch vehicle & spacecraft combination is essential for the study of the mechanical environment and the test condition design. In view of the inadequacy of the present ability of directly measuring the thrust pulsation and the transonic buffet, a method is put forward to inverting the mechanical load of the launch vehicle and spacecraft combination during the powered flight phase into other forms. Based on Duhamel's integration and the mode superposition algorithm,and with the help of quadratic polynomials, an arithmetic model is established for identifying the dynamic load of the multi-DOF vibration system. The result is compared with that obtained by the the precise time-integration method. It is shown that the new method enjoys a desirable anti-jamming capability(robustness) and a high precision of identification. Meanwhile, the problem of error accumulation is solved. By increasing the sampling frequency or decreasing the time step, more accurate results can be obtained, to provide a technological support for the related engineering applications.
The identification of the complicated mechanical loads in the ascent stage of the launch vehicle & spacecraft combination is essential for the study of the mechanical environment and the test condition design. In view of the inadequacy of the present ability of directly measuring the thrust pulsation and the transonic buffet, a method is put forward to inverting the mechanical load of the launch vehicle and spacecraft combination during the powered flight phase into other forms. Based on Duhamel's integration and the mode superposition algorithm,and with the help of quadratic polynomials, an arithmetic model is established for identifying the dynamic load of the multi-DOF vibration system. The result is compared with that obtained by the the precise time-integration method. It is shown that the new method enjoys a desirable anti-jamming capability(robustness) and a high precision of identification. Meanwhile, the problem of error accumulation is solved. By increasing the sampling frequency or decreasing the time step, more accurate results can be obtained, to provide a technological support for the related engineering applications.
引文
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[8]武江凯,白明生,张永.一种单自由度振动系统动态载荷识别方法[J].航天器环境工程,2016,33(2):136-140WU J K,BAI M S,ZHANG Y.The dynamic load identification for a single-degree-of-freedom vibration system[J].Space Environment Engineering,2016,33(2):136-140
[9]王静,陈海波,王靖,等.基于精细积分的冲击载荷时域识别方法研究[J].振动与冲击,2013,32(10):81-85WANG J,CHEN H B,WANG J,et al.Impulsive load identification in time domain based on precise timeintegration method[J].Journal of Vibration and Shock,2013,32(10):81-85
[2]HORST S,PATRICK G.A system load identification procedure for parallel robot manipulators[C]∥Mechanics of21st Century ICTAM04 Proceedings.Warsaw,Poland 2004:15-21
[3]LARS J L.Nordstrom,A dynamic programming algorithm for input estimation on linear time-variant system,compute method[J].Appl Mech Engrg,2006(195):6407-6427
[4]蔡元奇,朱以文.基于逆向滤波器的动态载荷时域识别方法[J].振动工程学报,2006,19(2):201-206CAI Y Q,ZHU Y W.Time domain identification method for dynamic loads based on inverse direction filter[J].Journal of Vibration Engineering,2006,19(2):201-206
[5]周盼,张权率志君,等.动载荷识别时域方法的研究现状与发展趋势[J].噪声与振动控制,2014,34(2):6-11ZHOU P,ZHANG Q,SHUAI Z J,et al.Review of research and development status of dynamic load identification in time domain[J].Noise And Vibration Control,2014,34(2):6-11
[6]蔡元奇.时域内动态载荷识别理论及实施技术研究[D].武汉:武汉大学,2004:35-37
[7]毛玉明.动载荷反演问题时域分析理论方法和实验研究[D].大连:大连理工大学,2010:8-11
[8]武江凯,白明生,张永.一种单自由度振动系统动态载荷识别方法[J].航天器环境工程,2016,33(2):136-140WU J K,BAI M S,ZHANG Y.The dynamic load identification for a single-degree-of-freedom vibration system[J].Space Environment Engineering,2016,33(2):136-140
[9]王静,陈海波,王靖,等.基于精细积分的冲击载荷时域识别方法研究[J].振动与冲击,2013,32(10):81-85WANG J,CHEN H B,WANG J,et al.Impulsive load identification in time domain based on precise timeintegration method[J].Journal of Vibration and Shock,2013,32(10):81-85