内编队引力参考敏感器构建的理论和方法研究

发布时间：2018-10-05 13:52

【摘要】：卫星重力测量、天基引力波探测等空间引力探测任务的成功实施有赖于对非引力作用的有效剔除或精确测量。通过构造验证质量块的纯引力轨道,内编队引力参考敏感器有效剔除了非引力干扰的影响,为高精度的空间引力探测任务提供了关键支撑。位于航天器质心附近的内编队引力参考敏感器主要由空腔结构、安装在腔体内壁的位移敏感器和包含其间的球形验证质量块组成,利用验证质量块与腔体结构的相对位移测量信息驱动航天器紧密跟踪验证质量块,来维持验证质量块的纯引力飞行状态。内编队引力参考敏感器无需对验证质量块施加悬浮控制力,更容易达到极低的非引力干扰抑制水平,是最为理想的纯引力轨道构造方式。本文以卫星重力测量任务为牵引,针对构建内编队引力参考敏感器亟需解决的相对测量和维持控制问题进行了系统研究,主要内容如下:对影响内编队引力参考敏感器性能的主要因素进行了分析,建立了验证质量块非引力干扰的频域指标分配模型,分别针对基于绝对轨道摄动的长波重力场测量和基于长基线相对轨道摄动的中高阶重力场测量任务,进行了内编队引力参考敏感器的指标分解。针对验证质量块的初始状态捕获和长波重力场测量任务需求,提出了基于光能探测阵列的相对测量系统概念,动态量程与腔体间隙相当,可达cm量级,精度优于1mm。通过提取探测阵列的有效输出单元中心坐标,给出了验证质量块的相对位移确定算法。分析了光压干扰的频谱分布,结果表明在光源周期性发光的工作模式下,测量干扰在10-11m/s2/(?)量级。构建了实验系统对研制的相对测量实验装置进行了性能测试,结果表明,在以验证质量块标称位置为中心,动态量程不小于±10mm的相对运动空间内,基于测量输出的最大定位误差为0.38mm。针对长基线相对轨道摄动重力场测量的高精度任务数据获取需求,采用了基于基掩光能量敏感的相对位移测量方法。考虑敏感器的几何布局,建立了验证质量块三位移与敏感器输出的关系模型。设计了可解析求解验证质量块位移的“三正交”和“两平行”敏感器布局方式。考虑测量光压、灵敏度和动态量程指标,推导了敏感器的主要设计参数约束。基于电子散粒噪声评估了掩光能量测量的极限精度,给出了极限精度为0.09nm/(?)的敏感器设计参数。建立了光斑尺寸变化、光功率波动、光束发散角、光束中心颤振和指向偏角的误差传递模型,并分析了球形边缘效应和光束衍射效应对误差传递关系的影响,结果表明建立的误差传递模型在进行误差预测时,准确度不低于19%。构建了掩光能量测量实验系统,实验结果表明在5mHz～0.1Hz的任务频段内,测量精度优于1μm/(?)。考虑验证质量块的球面波动、质心与形心偏差等球体加工误差,研究了基于掩光能量测量信息的验证质量块质心相对位移确定方法。基于球谐函数级数描述的验证质量块质心到球面距离模型,建立了包含非理想球体特征的掩光能量测量信号模型。基于频率辨识与测量信号拟合的思想,给出了等惯量验证质量块的质心位移确定方法,考虑到验证质量块较大的初始释放偏差,设计了全控制过程的质心位移确定方案。仿真验证了方法的有效性,结果表明在掩光能量测量精度为1nm/(?)、验证质量块转动频率～10Hz的条件下,球体质心位移确定精度在nm/(?),有效剔除了 10nm量级的球面波动和100nm量级的质心偏差影响。研究了维持控制下的内编队引力参考敏感器任务能力评估问题。考虑航天器与验证质量块的耦合效应,建立了内编队飞行的动力学模型。提出了基于H∞回路成形的鲁棒维持控制方法,能够满足任务频段内的非引力干扰抑制和球体质心位移确定指标要求。结合残余非引力干扰大小和验证质量块相对位移测量精度,分析了内编队引力参考敏感器支持下的长基线相对轨道摄动重力场测量任务能力。提出了内编队引力参考敏感器在低轨导航卫星方面的拓展应用概念,分析了残余非引力干扰对自主轨道预报误差的影响。结果表明,在非引力干扰的常值分量得到充分抑制、随机分量为1×10-11m/s2的条件下,内编队导航星的自主轨道预报可在三个月内保持m级精度。基于LQR控制律的仿真结果表明nm精度的高性能内编队引力参考敏感器可显著降低维持控制对航天器的功率和推进剂质量需求。
[Abstract]:The successful implementation of space gravity detection tasks such as satellite gravity measurement and space-based gravitational wave detection depends on the effective elimination or precise measurement of the non-gravity effect. By constructing the pure gravitational track of the verification mass block, the influence of non-gravity interference is effectively eliminated by the inner formation gravity reference sensor, and the key support is provided for the high-precision spatial gravity detection task. The inner formation gravity reference sensor located near the center of mass of the spacecraft is mainly composed of a cavity structure, a displacement sensor mounted on the inner wall of the cavity and a spherical verification mass block containing the cavity structure, and utilizing the relative displacement measurement information of the verification mass block and the cavity structure to drive the spacecraft to closely track and verify the mass block to maintain the pure gravitational flying state of the verification mass block. The inner formation gravity reference sensor does not need to apply suspension control force to the verification mass block, it is easier to reach extremely low non-attraction interference suppression level, and is the most ideal pure gravitational track structure mode. Based on the satellite gravity measurement task, this paper systematically studies the relative measurement and maintenance control problems which need to be solved in the construction of the inner formation gravity reference sensor, and the main contents are as follows: the main factors affecting the performance of the inner formation gravity reference sensor are analyzed. A frequency domain index distribution model for verifying the non-gravity interference of mass block is established, and the index decomposition of the inner formation gravity reference sensor is carried out aiming at the long-wave gravity field measurement based on absolute orbit perturbation and the middle-order high-order gravity field measurement task based on the relative orbit perturbation of long baseline. The concept of relative measurement system based on optical energy detection array is put forward aiming at the initial state capture and long-wave gravity field measurement task requirement of the verification mass block. The dynamic range is comparable to the cavity clearance, which can reach the order of cm, and the precision is better than 1mm. By extracting the center coordinates of the effective output unit of the detection array, the relative displacement determination algorithm of the verification mass block is given. The spectral distribution of optical interference is analyzed. The results show that the interference is 10-11m/ s2/ (?) on the order of magnitude. The performance test of the experimental system was constructed. The results show that the maximum positioning error based on the measurement output is 0. 38mm in the relative motion space with the nominal position of the verification mass block as the center and the dynamic range is not less than 1.10mm. Aiming at the high-precision task data acquisition requirement of long baseline relative orbit perturbation gravity field measurement, a relative displacement measurement method based on the basis mask energy sensitivity is adopted. Considering the geometrical layout of the sensor, a model of the relationship between the three displacement of the verification mass block and the output of the sensor is established. The paper designs the 鈥渢hree-orthogonal鈥，

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