面向激光跟踪仪宽频隔振器的理论分析及试验评价

Theoretical analysis and experimental evaluation of vibration isolation system with broadband characteristic for laser tracker

高能同步辐射光源施工现场,采用激光跟踪仪对高能光源磁铁设备标定、预准直和隧道测量时,激光跟踪仪受周边环境振动影响较大,并严重危害其测量精度.为了有效地控制环境振动的影响,提出一种面向激光跟踪仪的宽频隔振器,并安装在激光跟踪仪三角支架的支腿位置,在保证隔振性能的同时兼具较好的承载能力.针对上述系统,建立等效单自由度非线性动力学微分方程,采用复变量-平均法获得宽频隔振器的稳态响应解,并应用数值有限元方法验证理论模型及计算结果的正确性.在此基础上,采用谐波平衡法分析非线性系统的稳定性,并考虑关键设计参数K3对其隔振性能的影响.结合实际工作环境,选择部分典型工况(包括:长时间静压,垂向冲击激励和横向位移激励)进行实测,评估宽频隔振器的静态稳定性和振动控制效果.结果表明,长时间静压后,激光跟踪仪最大沉降位移约2×10^(–5)m;不同动态载荷作用下,宽频隔振器对激光跟踪仪振动响应幅值的衰减率最高可达97%,且有效隔振频带较宽;满足所有技术指标要求.

High-energy synchrotron radiation source,as a large scientific device,is under construction in Beijing,China.This device is one of the fourth-generation synchrotron radiation sources with the highest brightness in the world.It will provide an important support platform for basic science and engineering science.As a kind of high-precision large-scale measurement equipment,laser tracker is used mainly in high-energy particle accelerator equipment installation,precision poses dynamic measurement and antenna feed dynamic motion precision engineering measurement field.At the construction site of high energy synchrotron radiation source,the laser tracker is often used to calibrate and pre-collimate the high energy source magnet equipment and carry on the tunnel measurement.However,the laser tracker is easily affected by the vibration of the surrounding environment,and the adverse vibration seriously affects its measurement accuracy and even causes the equipment to damage.In order to effectively control the influence of environmental vibration and ensure good static bearing capacity,a broadband vibration isolator for laser tracker is proposed.It is installed in the leg position of the triangular bracket of the laser tracker,which ensures the vibration isolation performance and good bearing capacity.For the above system,the equivalent single freedom nonlinear dynamic differential equation is established,and the steady-state response solution of the broadband isolator is obtained by using the complex variable-average method.The numerical finite element method is used to verify the correctness of the theoretical model and corresponding calculation results.On this basis,the stability of a nonlinear system is analyzed by harmonic balance method,and the influence of key designing parameter K_(3)on vibration isolation performance is considered.Combined with the complexity of the actual working environment of laser tracker,a variety of typical working conditions are set up for test,including long time static pressure test,vertical impact excitation and lateral displacement excitation tests,to evaluate the static stability and vibration control effect of broadband isolator.The experimental results show that the maximum static displacement of the laser tracker is about 2×10^(-5)m under static pressure in a long time,and the maximum static load is within the allowable error range.When the occasional impacting is triggered,the installation of broadband isolator can make the combination quickly restore stability in about 2.95 s,exhibiting better vibration isolation performance.Under different dynamic loads,by comparing the acceleration frequency response curves of the laser tracker with and without the isolator,in the frequency band below the fundamental frequency of the laser tracker,the attenuation rate of the combined system can be up to about 97%with and without the vibration isolator.In the frequency band above the fundamental frequency,the attenuation rate of the combined system with and without the vibration isolation system can reach up to about 88%,and the effective vibration isolation frequency band is extended.The broadband vibration isolator meets all technical requirements.