微推力响应时间的实验研究  

Experimental study on the response time of microthrust

作　　者：丛麟骁 穆建超 龙建飞 柏树 郭宁 乔从丰 Linxiao Cong;Jianchao Mu;Jianfei Long;Shu Bai;Ning Guo;Congfeng Qiao(School of Physical Sciences,University of Chinese Academy of Sciences(UCAS),Beijing 100049,China;Key Laboratory of Vacuum Physics,UCAS,Beijing 100049,China;Gravitational Cosmic Taiji Laboratory(Beijing/Hangzhou),UCAS,Beijing 100049,China;School of Fundamental Physics and Mathematical Sciences,Hangzhou Institute for Advanced Study,UCAS,Hangzhou 310024,China)

机构地区：[1]School of Physical Sciences,University of Chinese Academy of Sciences(UCAS),Beijing 100049,China [2]Key Laboratory of Vacuum Physics,UCAS,Beijing 100049,China [3]Gravitational Cosmic Taiji Laboratory(Beijing/Hangzhou),UCAS,Beijing 100049,China [4]School of Fundamental Physics and Mathematical Sciences,Hangzhou Institute for Advanced Study,UCAS,Hangzhou 310024,China

出　　处：《Acta Mechanica Sinica》2023年第9期12-24,共13页力学学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2021YFC2202701);Major Scientific Instrument and Equipment Development Project of Chinese Academy of Sciences(Grant No.YJKYYQ20190059);the Fundamental Research Funds for the Central Universities.

摘　　要：微推进器广泛用于航天器无拖电和姿态控制任务中,例如重力科学和空间引力波探测,这些任务需要响应时间短于0.1秒的微推进器,其推力范围从μN到mN量级.本文开发了一种零位平衡摆,基于静电梳(ESF)脉冲宽度调制(PWM)的反馈控制来测量微推力的响应时间位移传感器、微控制器和ESF通过比例积分微分(PID)控制器连接在闭环中进行调谐,将扭摆限制在小偏转范围内,ESF施加的力等于代替微推进器的电磁线圈所加载的推力.PWM使激励电压和其推力响应之间的关系线性化,简化了二阶系统传递函数的z域拟合之后的校准.实验表明,在2Hz正弦扰动中,零位平衡摆的死区时间小于4毫秒,25μN阶跃响应的上升时间约为98毫秒.此外,本文还关注了几个关键问题,包括对二阶系统加死区的鲁棒控制、控制微分项引起的高频噪声、摆的低频噪声与推力噪声的分辨率界限、用单侧执行器在零位平衡中的不对称性、推力响应时间的幅度和初始相位的不确定性,以及在应用于实际推进器时性能的差异.未来,通过更新PWM量化位数,可以改善频率和精度之间的折衷,并将零平衡应用于振动隔离和噪声解耦等领域.Micro-thrusters have been widely used in spacecraft drag-free and attitude control missions,such as gravity science and space gravitational wave detection,where micro thrusters ranging fromμN to mN level are required with a response time shorter than O.1 s.A null-type pendulum is developed to measure the response time of micro thrust in the paper,based on feedback control on pulse width modulation(PWM)of electrostatic fins(ESF).The displacement sensor,micro-controller and ESF are connected in a close-loop tuned by proportional-integral-derivative(PID)controller.Constraining the pendulum within a small deflection,the force exerted by ESF equals the thrust loaded by solenoid as a replacement of micro-thrusters.The PWM linearizes the relationship between excitation voltage and its thrust response and simplifies the calibration of a second order system after a z-domain fit of the transfer function.The experiments showed the deadtime of the null balance is less than 4 ms by template matching in a 2 Hz sine disturbance,and the rise time of 25μN step response is about 98 ms.Besides,the paper also focuses on several key problems,which involved in the robust control of the second order system plus dead time,the vital high frequency noise to derivative term,the resolution boundaries to discriminate the low frequency balance's noise from the thrust's,the asymmetry buried in the null-balance using unilateral actuators,the uncertainties of response time in the magnitude and initial phase of thrust,as well as the difference in performance during the application of real thrusters.In the future,the trade-off between frequency and accuracy can be improved by updating the quantizers of PWM,and the null balance will be applied to the field such as vibration isolation and noise decoupling.

关 键 词：系统传递函数 位移传感器 激励电压 二阶系统 阶跃响应 反馈控制 微推进器 响应时间 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]