恒拉力系统的设计及系统固有频率和频响函数分析

Design of Constant Tension System and Analysis of Natural Frequency and Frequency Response Function

目的针对地面悬吊法模拟失重快速运动过程中较难实现恒定拉力的提供,设计一种能够实现较高精度的快速响应与补偿并能够稳定输出的恒拉力系统。方法首先依据低重力系统主动悬吊法原理设计恒拉力系统,其次根据拉格朗日定理推导系统动力学模型方程,最后通过MATLAB编译程序求解系统中执行部件频响函数。结果通过求解固有频率,改变参数去除了三阶固有频率奇异点,并得出各阶固有频率偏离电机减速机输出频率,同时得出激振频率与执行部件振幅关系。最终选定弹簧为40000 N/m,直线电机、支轨与压簧部分质量提升到13 kg,使得系统稳定输出,快速响应。结论构建了恒拉力系统,系统不会发生共振,执行部件共振点与平稳点对应的频率与自身质量和末端弹簧刚度有关,最终能够调整参数实现恒拉力系统快速响应与稳定输出。

Objective To achieve the constant tension in the process of rapid movement during ground weightlessness simulation by suspension,a constant tension system was designed which could achieve high precision,fast response and compensation,and stable output.Methods First,the constant tension system was designed according to the principle of active suspension of the low gravity system.Second,the system dynamic model equation was deduced according to the Lagrange＇s theorem.Finally,the frequency response function of the executing component in the system was solved by the MATLAB compiler program.Results By solving the natural frequency and changing the parameters,the singularity of the third-order natural frequency was removed,the natural frequencies of each order deviated from the output frequency of the motor reducer were obtained,and the relationship between the excitation frequency and the amplitude of the actuator was established.Finally,the spring is 40 000 N/m,the mass of linear motor,rail and spring is increased to 13 kg,which makes the system stable output and fast response.Conclusion The analysis showed that there would be no resonance in the system.The frequencies corresponding to the resonance point and the stationary point of the actuator were related to its own mass and the stiffness of the end spring.The parameters could be adjusted to achieve fast response and stable output of the constant tension system.