﻿ 伺服机构负载模拟系统设计与动态特性分析
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Design and analysis on dynamic characteristic of servo mechanism’s load simulation system
Zhang Peng, Fu Yongling, Guo Yanqing, Qi Xiaoye
School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Abstract:In view of a load simulating problem of servo mechanism in launch vehicles, a new load simulator device was present, which could simulate the inertia, friction, elastic, servo mechanism mounting rigidity and flexibility characteristics of engine nozzle by the mechanical structures. The complete mathematical models of servo mechanism and load simulator device were constructed. The influence of inertia, elastic and flexible to multiple degrees of freedom was analyzed by simulation. A sweep frequency test of servo mechanism was made to repeat the dynamic characteristics of servo mechanism in practical work when some loads of load simulator device were adjusted in a certain range. The test results validate the reasonableness of the proposed design, which may be a reference for the design of load simulator device with multiple degrees of freedom property. Besides, the simulator has got an actual application.
Key words: load simulation     servo mechanism     mathematical model     dynamic characteristic     multiple degrees of freedom

 图 1 伺服机构推动火箭尾喷管结构简图 Fig. 1 Structure diagram of servo mechanism to push launch vehicle engine

 图 2 伺服机构负载频率特性 Fig. 2 Frequency characteristic of servo mechanism
2 负载模拟系统结构模型

 图 3 伺服机构负载模拟系统原理图 Fig. 3 Principle of load simulation system
2.2 摩擦力矩负载

 图 4 弹性力矩加载结构简图 Fig. 4 Structure diagram of elastic torque loading device

 图 5 支撑刚度简化图 Fig. 5 Support stiffness adjusting device

 图 6 喷管柔性模拟等效简图 Fig. 6 Equivalent diagram of flexibility simulation for launch vehicle engine

 图 7 伺服机构负载模拟系统框图 Fig. 7 Block diagram of load simulation system
4 仿真分析及实验验证

 参数 数值 Ey/GPa 0.7 mT/kg 30 J/(kg/m2) 144.5 K/(N·m/rad) 5×106 Jz/(kg/m2) 30～60 kT/(N·m/(°)) 80～300 Mc/(N·m) 200

 图 8 Jz变化时的系统波特图 Fig. 8 Bode diagram of closed-loop system in changing Jz

 图 9 kT变化时系统波特图 Fig. 9 Bode diagram of closed-loop system in changing kT

 图 10 J变化时系统波特图 Fig. 10 Bode diagram of closed-loop system in changing J

 图 11 实验台扫频测试频率特性 Fig. 11 Magnitude-frequency characteristic of experimental station

1) 针对伺服机构负载多自由度特性模拟问题,提出了一种可模拟双谐振峰的负载模拟系统,通过机械的方式完成伺服机构惯性负载、摩擦负载、弹性负载、支撑刚度以及喷管柔性的模拟.

2) 对负载模拟系统进行了数学模型的推导和仿真分析,讨论了负载模拟系统中弹性负载、转动惯量和喷管柔性模拟质量块对实验整体系统幅频特性的影响.

3) 最后,通过实验验证了所设计的负载模拟系统,调整可变负载可以复现伺服机构实际工作过程的动态特性,验证了所建立的数学模型的正确性以及机构设计的合理性,为类似负载模拟系统的研制提供了理论基础和设计思路.

#### 文章信息

Zhang Peng, Fu Yongling, Guo Yanqing, Qi Xiaoye

Design and analysis on dynamic characteristic of servo mechanism’s load simulation system

Journal of Beijing University of Aeronautics and Astronsutics, 2014, 40(9): 1225-1230.
http://dx.doi.org/10.13700/j.bh.1001-5965.2013.0571