PMSM电流预测控制参数误差量化分析方法

交流永磁同步电机（PMSM）电流环控制性能是制约交流伺服系统性能的关键。电流预测控制拥有更快的动态响应、更低的电流谐波和优良的转矩响应，但该算法依赖精确的电机模型，参数失配会引发稳态电流误差，无法输出额定转矩，进而导致电机转矩输出效率降低。根据永磁同步电机电流预测模型，详细分析了d、q轴电流静差产生的原因，以及电流预测控制对电机参数误差的敏感性，提出了一种参数误差量化分析方法。该方法引入了电机参数偏差因子，量化描述了电机电感、磁链参数误差与电流静差之间的制约关系。通过仿真分析，验证了所提方法的合理性，为高性能永磁伺服电流预测数字控制技术打下了良好基础。     

航天器自主导航状态估计方法研究综述

自主导航是航天器自主运行的核心关键技术。状态估计是实现航天器自主导航的核心手段，是指实时确定航天器在轨位置、速度和姿态等导航参数，是航天器自主导航技术的重点发展方向之一。首先，针对航天器自主导航的实际需求，阐述了研究航天器自主导航状态估计方法的必要性，具体从导航系统可观测性分析、导航滤波算法、导航系统误差补偿3个方面介绍了航天器自主导航状态估计方法的研究现状；然后，分析并总结状态估计方法在航天器自主导航系统中的实际应用；最后，结合理论研究和实际应用，给出了状态估计方法目前存在的主要问题并对其后续发展进行了展望。     

Framework and development of data-driven physics based model with application in dimensional accuracy prediction in pocket milling

In the manufacturing of thin wall components for aerospace industry, apart from the side wall contour error, the Remaining Bottom Thickness Error (RBTE) for the thin-wall pocket component (e.g. rocket shell) is of the same importance but overlooked in current research. If the RBTE reduces by 30%, the weight reduction of the entire component will reach up to tens of kilograms while improving the dynamic balance performance of the large component. Current RBTE control requires the off-process measurement of limited discrete points on the component bottom to provide the reference value for compensation. This leads to incompleteness in the remaining bottom thickness control and redundant measurement in manufacturing. In this paper, the framework of data-driven physics based model is proposed and developed for the real-time prediction of critical quality for large components, which enables accurate prediction and compensation of RBTE value for the thin wall components. The physics based model considers the primary root cause, in terms of tool deflection and clamping stiffness induced Axial Material Removal Thickness (AMRT) variation, for the RBTE formation. And to incorporate the dynamic and inherent coupling of the complicated manufacturing system, the multi-feature fusion and machine learning algorithm, i.e. kernel Principal Component Analysis (kPCA) and kernel Support Vector Regression (kSVR), are incorporated with the physics based model. Therefore, the proposed data-driven physics based model combines both process mechanism and the system disturbance to achieve better prediction accuracy. The final verification experiment is implemented to validate the effectiveness of the proposed method for dimensional accuracy prediction in pocket milling, and the prediction accuracy of AMRT achieves 0.014 mm and 0.019 mm for straight and corner milling, respectively.     

Modeling and experiment of grinding wheel axial profiles based on gear hobs

Hobbing is one of the crucial gear manufacturing processes with high precision and high efficiency. In order to improve the accuracy of hobbing and hob relief grinding, more precise grinding wheels are demanded for relief grinding in the production of gear hobs. In this paper, a new and accurate mathematical method for calculating the axial profile of grinding wheel based on the corresponding gear hob to be ground is proposed. Considering that most researches have been conducted to focus on the optimization of hob geometric feature and only can be applied to a specific type of hand of helix and rake angle of gear hobs. The method in this paper can be served as a general algorithm for generating axial profile of grinding wheels on the basis of the spatial envelope theory, the principle of coordinate system transformation, and studies on normal profile of single-tooth. The accuracy of grinding hobs is based on applying the approach in practical manufacturing. Taking two typical different kinds of pre-grinding gear hobs as examples for calculation and experiment, the results of tooth profile errors strengthen the position that the validity and feasibility of this method, it can be employed for gear hob design and grinding processing.     

运载火箭主动段自适应增广控制

针对运载火箭上升段在复杂飞行环境、大不确定性干扰和振动等因素的影响下，传统PID控制方法难以满足高品质控制需求的问题，进行了自适应增广控制(AAC)方法研究，以实现对运载火箭姿态的精确控制。在深入分析自适应增广控制系统整体构架的基础上，通过标称PID控制器设计与基于粒子群优化(PSO)的数字滤波器设计实现了刚体控制及对弹性振动的抑制；继而针对大范围干扰、不确定性和由于滤波器切换产生的弹性振动影响，设计了在线调整算法自适应调节PID控制增益，并对其工作机理与参数设计原则进行研究；然后设计干扰补偿回路和主动减载回路以减小内外扰动、弹性振动和风载荷影响；最后在弹性振动、风干扰和参数不确定性等因素同时作用的状态下进行仿真分析，验证了自适应增广控制系统能够有效应对运载火箭主动段复杂飞行环境的影响，大幅度提升综合控制性能，具有理论研究意义与工程应用价值。     

Experimental and numerical investigation on surface quality for two-point incremental sheet forming with interpolator

The unsatisfied surface quality seriously impedes the wide application of incremental sheet forming (ISF) in industrial field. As a novel approach, the interpolator method is a promising strategy to enhance the surface quality in ISF. However, the mechanism for the improvement of surface quality and the influence of interpolator properties on surface roughness are not well understood. In this paper, the influences of process variables (i.e. tool diameter, step size and thickness of interpolators) on the forming process (e.g. surface roughness, forming force and geometric error) are investigated through a systematic experimental approach of central composite design (CCD) in two-point incremental sheet forming (TPIF). It is obtained that the increase in thickness of interpolators decreases the surface roughness in direction vertical to the tool path while increases the surface roughness in direction horizontal to the tool path. Nevertheless, the combined influence between thickness of interpolators and process parameters (tool diameter and step size) is limited. Meanwhile, the placement of interpolator has little influence on the effective forming force of blank. In addition, the geometric error enlarges with the increase of step size and thickness of interpolator while decreases firstly and then increase with an increase in tool diameter. Finally, the influencing mechanism of the interpolator method on surface quality can be attributed to the decrease of the contact pressure due to the increase of contact area with the unchanged contact force. Meanwhile, the interpolator method eliminates the sliding friction on the surface of blank due to the stable relative position between the blank and the interpolator.     

相位检测误差对核磁共振陀螺输出频率的影响

针对核磁共振陀螺中采用相位检测方案时可能引起额外频率误差的问题,提出了通过控制电子顺磁共振失谐量及静磁场扰动来抑制额外频率误差的方案。基于Bloch方程,推导了惰性气体原子系综输出频率的表达式,并将相位检测的过程包含在内。建立了考虑相位检测误差的核磁共振陀螺频率误差方程,给出了相位检测引入的额外频率误差表达式并进行了数值仿真。仿真结果表明,通过设定合适的共振失谐量,其额外频率误差至少可以抑制1个数量级,而通过精确地抑制静磁场的一阶及二阶扰动,可以进一步抑制1～3个数量级,将额外频率误差降低到nHz量级。     

直线模拟加载系统的研究进展与发展趋势

直线模拟加载系统是一种用于在实验室条件下模拟承载对象工作时所受直线负载力的半实物仿真系统，可用于模拟各类飞行器关键部件在工作过程中所受的气体阻力载荷。针对目前常用的机械式、电液式和电动式直线模拟加载系统，分析其基本加载原理和研究进展，结合自行研制的电动式直线模拟加载系统进行了深入探讨。针对多余力抑制方法的关键问题，详细论述了直线负载模拟器的结构补偿方法和控制策略。最后，展望了直线模拟加载系统的发展趋势，归纳了电动式直线模拟加载系统的高精度、大载荷发展方向。     

正十烷简化机理的构建及其在发动机燃烧数值模拟中的应用

发动机燃烧室中燃料的能量释放与燃烧特性对于发动机设计具有重要作用，为了预测发动机点火包线和贫/富油极限等关键性能，迫切需要发展航空燃料及其典型组分的高精度化学动力学模型。本文针对燃料典型组分正十烷，采用自主开发的机理生成程序ReaxGen构建了其燃烧详细机理（1499种组分、5713步反应）。为了验证机理的合理性与可靠性，在当量比Φ=0.5-2.0，压力P=1-80 atm的宽工况条件下进行了点火延迟模拟验证，结果表明本文提出的正十烷详细机理在较宽的温度、压力和当量比条件下具有较高的模拟精度。为获得适用于发动机燃烧模拟的高精度简化机理，本文基于误差传播的直接关系图方法简化了正十烷燃烧详细机理，得到包含709种组分、2793步反应的正十烷半详细机理。进一步在高温范围（1000-1500 K），采用路径通量分析方法简化得到含77种组分、359个反应的骨架机理。获得的骨架机理能够合理描述正十烷在高温下的燃烧特性，且该骨架机理尺度规模可用于基于火焰面模型的燃烧数值模拟。基于此高精度的骨架机理模型，结合火焰面生成流形湍流燃烧模型，采用大涡模拟方法进行了航空发动机环形燃烧室单头部扇形的燃烧模拟，初步获得了非稳态流场结构，其中温度模拟结果与实验值基本符合。     

利用视加速度补偿和推力逐级释放的垂直着陆制导方法

针对运载火箭子级垂直返回着陆段的制导问题，本文在应用凸优化的滚动时域在线规划基础上研究了制导鲁棒性的改善策略。为应对着陆后期控制能力不足的情况，在滚动规划过程中引入了推力上界逐级释放的策略。同时，考虑缓解干扰和误差累积的影响，在制导周期内引入视加速度信息对在线规划的推力指令进行补偿，以进一步改善滚动规划的递归可行性。最后，通过数值算例仿真及对比分析验证所提出的补偿策略的有效性。