高精度多自由度航天器模拟器关键技术及实验研究

发布时间：2018-01-02 04:13

本文关键词：高精度多自由度航天器模拟器关键技术及实验研究　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：多自由度航天器模拟器被广泛应用于在地面研究航天器的动力学、制导、导航与控制。采用气悬浮技术,模拟器可实现在地面的无摩擦微重力的自由运动。利用多自由度模拟器可在地面进行相关空间任务实验,验证各类算法,可有效降低在轨飞行器任务的风险,同时模拟器本身具有成本低、可重复性高等优点。国内外很多研究机构已开始研究各类模拟器,并用于编队飞行、交会对接等方面的研究。模拟器关键技术的研究是地面仿真效果和精度的保证。针对模拟器的关键技术和仿真实验中的关键算法,论文主要开展了如下研究工作:针对模拟器需要实现的仿真功能,论文首先给出了模拟器的总体方案设计,基于平面气浮轴承和球面气浮轴承实现二维平动和三轴转动,对模拟器的各分系统进行了简要的概述。针对模拟器的质心调平问题,设计自动的质心配平系统,实现对模拟器质心在空间三个方向的独立调节,并分析了配平质量块调整量与模拟器质心变化量之间的关系。进一步针对质心和惯量的独立调节问题,设计了一种质心惯量独立调节系统并提出了调节方法。最后建立了包括配平系统的模拟器姿态动力学模型,同时给出配平质量块移动量与模拟器惯量之间的关系。针对模拟器惯性参数设计需求——模拟器的惯性参数与实际航天器的惯性参数一致或者是航天器的缩比,提出对模拟器上设备安装方位优化的方法。将空间约束问题简化为二维平面上的几何约束,给出几何约束的不等式表示方式。针对质心的配平问题,提出了一种快速的自动配平方法。通过姿态稳定控制的输出力矩估计质心的偏差量,配平系统实现质心快速调节。针对模拟器的参数辨识问题,将飞轮的输出力矩作为模拟器参数辨识的激励力矩,提出了跟踪微分器(TD)滤波器结合最小二乘法(RLS)的系统辨识方法,TD和离散最小二乘法都不需要噪声信息。两种结合方式TD-TD-RLS和ETD(Extended TD)-RLS都有较强的噪声抑制效果。若无较大干扰力矩,ETD-RLS有更快的收敛速度;TD-TD-RLS方法对非零均值的干扰力矩有更好的收敛精度。之后采用EKF方法实现状态量和未知惯性参数的同时估计,并分析了方法的可观性。针对辨识的效率和模拟器转动范围限制问题,提出了一种次优激励的求取方法。根据惯性参数的粗略值,以积分形式的条件数作为性能指标,采用高斯伪谱法对优化问题离散化,进而优化得到激励轨迹。针对航天器对接地面模拟的逼近轨迹问题,考虑目标航天器的自旋和太阳帆板的阻碍,设计绕飞逼近轨迹和最优能量逼近轨迹。绕飞逼近轨迹更适用于自旋速度较小,与目标距离较近的情况。绕飞逼近轨迹到达目标位置后可与目标航天器模拟器保持相对稳定,便于对接过程实现。最优的逼近轨迹是最终时间tf的函数,且以最优能量逼近目标位置。然后给出了最优轨迹的正面对接范围和两段最优轨迹的避障策略。之后,针对交会对接过程的有下滑力干扰的控制问题,设计了模拟器交会过程的逼近轨迹,采用自抗扰控制实现对模拟器交会对接过程的高精度控制。给出了冷喷气的推力分配策略,并通过PWM方式实现对推力大小的等效控制。
[Abstract]:Dynamic, multi DOF spacecraft simulator is widely used in spacecraft on the ground of guidance, navigation and control. Using gas suspension technology, can realize the ground simulator without friction free movement. Microgravity can be related to space missions in the ground experiment utilizing the multi degree of freedom simulator, verify the various algorithms, can effectively reduce the risk in orbit the aircraft task, at the same time the simulator itself has the advantages of low cost, the advantages of higher repeatability. Many domestic and foreign research institutions have begun to study all kinds of simulators, and for formation flight, rendezvous and docking and other aspects of the research. The key technology of the simulator is ground simulation effect and accuracy. Aiming at the key algorithm of key technology and simulation simulator the paper carried out the research work as follows: according to the need to achieve the simulation function of simulator, this paper first presents the simulator The scheme of plane air bearing and spherical air bearing to achieve two-dimensional translation and three rotation based on a brief overview of the system simulator. According to the centroid Leveling Problem simulator, design the centroid trim system automatically, realize the adjustment of the simulator centroid of three directions in space independently, and analysis the relationship between the quantity and quality balance adjustment. Further simulator centroid variation in centroid and inertia of the independent regulation problem, design a mass inertia independent regulation system and puts forward the regulation method. Finally established including simulator attitude dynamics model of trim system, at the same time, given the relationship between quantity and quality balance block movement simulator in view of the inertia. Inertia parameters of inertial parameters of simulator inertial parameters consistent with the actual needs of the simulator of spacecraft or spacecraft The shrinkage ratio, propose the method of the optimum equipment installation simulator. The space constraint problem is simplified to 2D geometric constraint, inequality of geometric constraint representation. According to the centroid of balancing problem, put forward a fast automatic balancing method. The output torque of attitude stabilization control estimation deviation of centroid the trim system realization of centroid rapid adjustment. For the parameter identification problem of the simulator, the output torque of the flywheel simulator as the parameter identification of excitation torque, the tracking differentiator (TD) filter with minimum two multiplication (RLS) system identification methods, TD and discrete least squares method without noise information. The two kinds of combination TD-TD-RLS and ETD (Extended TD -RLS) has strong noise suppression effect. If there is no large disturbance moment, ETD-RLS has faster convergence speed; TD-TD-RLS method of non zero mean The disturbance torque values has a better convergence accuracy estimation. After using the EKF method to achieve state and unknown inertial parameters at the same time, and analyzed the observability method. According to the identification efficiency and the simulator rotation range limitation, method of obtaining a suboptimal incentive is proposed. According to the inertial parameters of the rough value. In the integral form of the condition number as the performance index, using Gauss pseudospectral method to the optimization problem of discrete optimization and incentive for trajectory. The trajectory of the spacecraft docking simulation approaching ground, considering the target spacecraft spin and solar array block design flying trajectory and optimal approximation energy approximation trajectory. Flying trajectory more approaching for the spin speed is small, and the distance is closer. Fly around the approaching track to the target position can keep relatively stable and the target spacecraft simulator for docking Process to achieve optimal trajectory approximation. Finally TF is a function of time, and the optimal energy approximation of target location. And then the obstacle avoidance strategy of optimal trajectory front butt range and the two optimal trajectory. Then, aiming at the rendezvous and docking process control the problem of declining the interference force, the design process of rendezvous trajectory approximation simulator, the ADRC can realize high precision control of the simulator of docking procedure is given. The thrust allocation strategy of the cold jet, and to achieve equivalent thrust control by way of PWM.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：V416.8

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