A novel strategy of smart manipulation by micro-scale oscillatory networks of the reactionary zones for enhanced extreme thrust control of the next-generation solid propulsion systems

The main aim of this research is to get a better knowledge and understanding of the micro-scale oscillatory networks behavior in the solid propellants reactionary zones. Fundamental understanding of the micro-and nano-scale combustion mechanisms is essential to the development and further improvement of the next-generation technologies for extreme control of the solid propellant thrust. Both experiments and theory confirm that the micro-and nano-scale oscillatory networks excitation in the solid propellants reactionary zones is a rather universal phenomenon. In accordance with our concept,the micro-and nano-scale structures form both the fractal and self-organized wave patterns in the solid propellants reactionary zones. Control by the shape, the sizes and spacial orientation of the wave patterns allows manipulate by the energy exchange and release in the reactionary zones. A novel strategy for enhanced extreme thrust control in solid propulsion systems are based on manipulation by selforganization of the micro-and nano-scale oscillatory networks and self-organized patterns formation in the reactionary zones with use of the system of acoustic waves and electro-magnetic fields, generated by special kind of ring-shaped electric discharges along with resonance laser radiation. Application of special kind of the ring-shaped electric discharges demands the minimum expenses of energy and opens prospects for almost inertia-free control by combustion processes. Nano-sized additives will enhance self-organizing and self-synchronization of the micro-and nano-scale oscillatory networks on the nanometer scale. Suggested novel strategy opens the door for completely new ways for enhanced extreme thrust control of the solid propulsion systems.

Neural network-based model predictive control with fuzzy-SQP optimization for direct thrust control of turbofan engine

A nonlinear model predictive control method based on fuzzy-Sequential Quadratic Programming(SQP)for direct thrust control is proposed in this paper for the sake of improving the accuracy of thrust control.The designed control system includes four parts,namely a predictive model,rolling optimization,online correction,and feedback correction.Considering the strong nonlinearity of engine,a predictive model is established by Back Propagation(BP)neural network for the entire flight envelope,whose input and output are determined with random forest algorithm and actual situation analysis.Rolling optimization typically uses SQP as the optimization algorithm,but SQP algorithm is easy to trap into local optimization.Therefore,the fuzzy-SQP algorithm is proposed to prevent this disadvantage using fuzzy algorithm to determine the initial value of SQP.In addition to the traditional three parts of model predictive control,an online correction module is added to improve the predictive accuracy of the predictive model in the predictive time domain.Simulation results show that the BP predictive model can reach a certain degree of predictive accuracy,and the proposed control system can achieve good tracking performance with the limited parameters within the safe range。

Direct thrust control for multivariable turbofan approach

A novel turbofan Direct Thrust Control(DTC)architecture based on Linear ParameterVarying(LPV)approach for a two-spool turbofan engine thrust control is proposed in this paper.Instead of transforming thrust command to shaft speed command and pressure ratio command,the thrust will be directly controlled by an optimal controller with two control variables.LPV model of the engine is established for the designing of thrust estimator and controller.A robust LPV H∞filter is introduced to estimate the unmeasurable thrust according to measurable engine states.The thrust estimation error system is proved to be Affinely Quadratically Stable(AQS)in the whole parameter box with a prescribed H∞performance indexγ.Due to the existence of overdetermined equations,the solving of controller parameters is a multi-solution problem.Therefore,Particle Swarm Optimization(PSO)algorithm is used to optimize the controller parameters to obtain satisfactory control performance based on the engine’s LPV model.Numerical simulations show that the thrust estimator can acquire smooth and accurate estimating results when sensor noise exists.The optimal controller can receive desired control performance both in steady and transition control tasks within the engine working states above the idle,verifying the effectiveness of the proposed DTC architecture’s application in thrust direct control problem.

Reduced-dimensional MPC controller for direct thrust control

With the development of the aircraft gas turbine engine, a control system should be able to achieve effective thrust control to gain better operability. The main contribution of this paper is to develop a novel direct thrust control approach based on an improved model predictive control method through a strategy that reduces the dimension of control sequence. It can not only achieve normal direct thrust control tasks but also maximize the thrust level within the safe operation boundaries. Only the action of switching the objective functions is required to achieve the switch of these two thrust control modes while there is no modification to the control structure. Besides,a shorter control sequence is defined for multivariable control by updating only one control variable at every simulation time instant. Therefore, the time requirement for the solving process of the optimal control sequence is reduced. The proposed controller is implemented to a twin-spool engine.Simulations are conducted in the wide flight envelope, and results show that the average timeconsumption can be reduced up to 65% in comparison with the standard model predictive control,and the thrust can be increased significantly when maximum thrust mode is implemented by using engine limit margins.

BOOSTING SPARSE LEAST SQUARES SUPPORT VECTOR REGRESSION (BSLSSVR) AND ITS APPLICATION TO THRUST ESTIMATION

In order to realize direct thrust control instead of conventional sensors-based control for aero-engine, a thrust estimator with high accuracy is designed by using the boosting technique to improve the performance of least squares support vector regression （LSSVR）. There exist two distinct features compared with the conven- tional boosting technique： （1） Sampling without replacement is used to avoid numerical instability for modeling LSSVR. （2） To realize the sparseness of LSSVR and reduce the computational complexity, only a subset of the training samples is used to construct LSSVR. Thus, this boosting method for LSSVR is called the boosting sparse LSSVR （BSLSSVR）. Finally, simulation results show that BSLSSVR-based thrust estimator can satisfy the requirement of direct thrust control, i.e. , maximum absolute value of relative error of thrust estimation is not more than 5‰.

INVESTIGATION OF FLIGHT DYNAMICS OF THRUST VECTORING AIRCRAFT USING EXTENDED CONTINUATION METHODS

This paper presents the flight dynamical behavior of the thrust vectoring aircraft with extended bifurcation and continuation methods. In contrast to the standard bifurcation and continuation methods, the extended methods are capable of calculating the continuation curves of the equilibrium points for the particular type of trimming flight. Therefore, these methods can not only give the performance measures of aircraft, but also determine the stability of trimming points. In this paper, the methods are used to verify the effectiveness of the thrust vectoring control law, to define the flight envelope boundary, to analyze the stability and controllability of trimming flight, and to predict the departures of the instable flight. The result shows that the extended methods provide more flight dynamic information and are useful in preliminary design of the thrust vectoring aircraft.

Thrust estimator design based on least squares support vector regression machine

In order to realize direct thrust control instead of traditional sensor-based control for aero-engines,it is indispensable to design a thrust estimator with high accuracy,so a scheme for thrust estimator design based on the least square support vector regression machine is proposed to solve this problem. Furthermore,numerical simulations confirm the effectiveness of our presented scheme. During the process of estimator design,a wrapper criterion that can not only reduce the computational complexity but also enhance the generalization performance is proposed to select variables as input variables for estimator.

STUDIES ON AIRCRAFT TOTAL ENERGY FLIGHT CONTROL SYSTEM：NONLINEAR SYSTEM INTEGRATION AND SIMULATION

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Novel TPN control algorithm for exoatmospheric intercept

A novel control algorithm with fixed pulse thrust, based on true proportional navigation（TPN）, is proposed for exoatmospheric intercept.According to the TPN guidance law and pulse thrust characteristics, the principle of control command is presented, the control stability and precision are analyzed.With the help of the TPN guidance law, the algorithm can automatically modulate the turn-on time and duration of the thrust, which could effectively limit the impact of measure noise of the line-of-sight（LOS） angle and rate on the interception miss-distance.At last, the number-theoretic method（NTM） is introduced to acquire the relation between control algorithm and miss-distance, even as it simulates the intercept process with initial state noise.And the reliability of the algorithm is demonstrated with the simulation result.

Numerical Investigation of Plasma Active Flow Control

Based on the theory of EHD （electronhydrodynamic）, a simplified volume force model is applied to simulation to analyze the traits of plasma flow control in flow field, in which the cold plasma is generated by a DBD （dielectric-barrier-discharge） actuator. With the para- electric action of volume force in electric field, acceleration characteristics of the plasma flow are investigated for different excitation intensities of RF （radio frequency） power for the actuator. Furthermore, the plasma acceleration leads to an asymmetric distribution of flow field, and hence induces the deflection of jet plume, then results in a significant deflection angle of 6.26° thrustvectoring effect. It appears that the plasma flow control technology is a new tentative method for the thrust-vectoring control of a space vehicle.

Predictive control for satellite formation keeping

Based on a Hill equation and a nonlinear equation describing the desired and real dynamics of relative motion separately, a predictive controller is brought forward, which makes the real state track the desired ones to keep satellite formation. The stability and robustness of the controller are analyzed. Finally, comparing the simulation results of the proposed controller with that of the traditional, proportional-differential controller shows that the former one is capable of keeping the satellite formation more favorably, considering the disturbances such as the J2 perturbations.

塔里木盆地西北缘沙井子断裂带的构造特征与形成演化

塔里木盆地西北缘的沙井子断裂带,位于塔北隆起的温宿凸起和北部坳陷的阿瓦提凹陷之间。它是塔里木盆地的一条一级断裂带,由沙井子断裂、英雄断裂、温宿断裂和沙南断裂组成。其中沙井子断裂是主干断裂,其它3条是其分支断裂。本轮研究新发现温宿分支断裂,并将沙南断裂解释为英雄断裂前缘的反冲断层,归属沙井子断裂带。沙井子断裂带的雏形形成于奥陶纪末—志留纪初,在泥盆纪末—石炭纪、二叠纪末—三叠纪初、侏罗纪末—白垩纪初、白垩纪末—古近纪初和新近纪—第四纪发生过多期冲断作用和新近纪末—第四纪初的张扭性构造变形后,才最终定型。沙井子断裂带是一条断控油气富集区带,温宿油田、托探1油藏、沙南1油藏、新苏地1油气藏等都受其控制。

Simulation for the Controlling Factors of Structural Deformation in the Southern Margin of the Junggar Basin

According to the differences of structural deformation characteristics, the southern margin of the Junggar basin can be divided into two segments from east to west. Arcnate thrust-and-fold belts that protrude to the north are developed in the eastern segment. There are three rows of en echelon thrust-and-fold belts in the western segment. Thrust and fold structures of basement-involved styles are developed in the first row, and decollement fold structures are formed from the second row to the third row. In order to study the factors controlling the deformation of structures, sand-box experiments have been devised to simulate the evolution of plane and profile deformation. The planar simulation results indicate that the orthogonal compression coming from Bogeda Mountain and the oblique compression with an angle of 75° between the stress and the boundary originating from North Tianshan were responsible for the deformation differences between the eastern part and the western part. The Miquan-Uriimqi fault in the basement is the pre-existing condition for generating fragments from east to west. The profile simulation results show that the main factors controlling the deformation in the eastern part are related to the decollement of Jurassic coal beds alone, while those controlling the deformation in the western segment are related to both the Jurassic coal beds and the Eogene clay beds. The total amount of shortening from the Yaomoshan anticline to the Gumudi anticline in the eastern part is -19.57 km as estimated from the simulation results, and the shortening rate is about 36.46%; that from the Qingshuihe anticline to the Anjihai anticline in the western part is -22.01 km as estimated by the simulation results, with a shortening rate of about 32.48%. These estimated values obtained from the model results are very close to the values calculated by means of the balanced cross section.

INVESTIGATION ON THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO THE SPILL GROOVED THRUST BEARING

An application of the boundary element method (BEM) is presented to calculate the behaviors of a spiral grooved thrust bearing (SGTB). The basic reason is that the SGTB has very complex boundary conditions that can hinder the effective or sufficient applications of the finite difference method (FDM) and the finite element method (FEM), despite some existing work based on the FDM and the FEM. In other to apply the BEM, the pressure control equation, i. e., Reynolds' equation, is first transformed into Laplace's and Poisson's form of the equations. Discretization of the SGTB with a set of boundary elements is thus explained in detail, which also includes the handling of boundary conditions. The Archimedean SGTB is chosen as an example of the application Of BEM, and the relationship between the behaviors and structure parameters of the bearing are found and discussed through this calculation. The obtained results lay a solid foundation for a further work of the design of the SGTB.

Hardware-in-loop simulation on hydrostatic thrust bearing worktable pose

A controllable hydrostatic thrust bearing was presented to improve rigidity. The bearing worktable poses were controlled by coupling oilfilm thickness of four controllable chambers. The chamber flow can be regulated by electro hydraulic servo valve-control variable pump according to the surface roughness, load, cutting force, and thermal effects of worktable. The mathematical models of the controllable chamber flow, servo variable mechanism and controller were built. The pose control model was established, which contained the kinematics positive and negative solution and control strategy of feedforward and hydraulic cylinder position feedback. Hardware-in-loop simulation experiment was carried out on the electro hydraulic servo test bench by means of the non-linear relation of film thickness and hydraulic cylinder displacement. Hardware-in-loop simulation experiment results show that the controllable bearings exhibit high oilfilm rigidity, the rising time is 0.24 s and the maximum overshoot is 2.23%, and can be applied in high precision heavy machine tool.

基于冗余执行器的航空发动机推力快速响应控制方法研究

面向飞/推一体化控制需求,开展涡扇发动机推力快速响应控制研究,提出了适用于推力最小相位系统的冗余控制方案。研究内容包括:(1)借鉴阀位控制思想,提出在传统燃油流量(Wf)回路基础上增设尾喷口喉道面积(A8)回路,通过挖掘冗余执行器变化速率潜力,提高推力响应速度,降低了对于燃油泵快速作动的需求,同时该方法可以使喷口在推力响应过程逐渐回中,系统具备持续的推力快速调节能力;(2)分析了A8调节推力的物理机理,指出容腔压力动力学主导的部件间流量匹配过程使得A8对推力具有直馈作用,是提高推力响应速度的有效途径。基于发动机部件级模型的评估结果表明,本文提出的方法在执行机构存在速率限制的情况下,实现了推力10 rad/s闭环带宽和A8回中的设计目标,方法可行、有效。在推力响应过程中,A8直馈作用对推力变化的贡献度最高时超过50%。随着对于推力控制模式和推力响应速度的日趋关注,应对容腔内的压力动态过程给予充分的重视。

双机械臂布局下的电推进位保策略

对于地球同步轨道的电推进卫星,可采用双机械臂式电推布局进行轨道维持控制.本文研究了双机械臂式电推布局的自主位保控制策略,针对南北各一台机械臂,每台机械臂分别配置一台电推力器的布局方式,通过每天1~2次点火,以尽量少的点火指向变动实现东西/南北联合位保控制.在双侧机械臂、电推力器正常情况下研究具有解析形式的在轨位保算法.研究基于单侧矢量调节机构和该侧电推力器的故障位保策略,给出衡量不同矢量机构能力和推力比冲下的位保效率衡量方法.仿真结果表明,正常/故障情况下的位保控制精度均能够满足同步轨道位保控制要求.本算法为解析形式,计算量较小,可以实现多星共轨和定点捕获/轨位漂移,便于量上自主实施.

安徽宣城矿集区控矿构造特征及其深部找矿指示意义

宣城矿集区因近年发现了茶亭斑岩型铜金矿、长山热液型铅锌矿等大-中型矿产地而成为长江中下游成矿带较热门矿集区之一。通过详细的野外调查和系统分析,本文厘定了研究区北东向构造格架为一条深大断裂带、两个坳陷盆地、三条逆冲推覆构造带,其中推覆构造带由多个自南东向北西运动的倒转复式褶皱和叠瓦状逆冲岩席组成。根据典型矿床控矿构造解析,明确了江南深大断裂和深部主推覆构造是区内一级控岩控矿构造,北东向断裂带及其次级构造、推覆体上盘倒转褶皱转折端和翼部、层间破碎带、五通组与黄龙-船山组的“硅钙面”、燕山晚期中酸性侵入岩与碳酸盐岩的接触带等为区内重要的控矿、容矿构造,并据此提出了该区下一步深部找矿方向。

基于冷流推力的变微过载控制方法研究

针对地面微重力环境下的变微过载控制方法,以不同冷流压力以及二次流入射位置等因素,开展了基于冷流推力的流场仿真,分析了二次射流对主流流场影响。并研制了冷流推力系统,通过测试验证了冷流推力与总压的相互关系。并通过微重力落舱开展了1s微重力环境下的变微过载试验,结果表明通过冷流流场型面设计,以及主流、二次流压力的控制可以控制作用于内舱的推力,从而改变内舱微重力环境下的微重力水平,满足在微重力环境下的变微过载控制能力。

基于推力矢量分配的ROV姿态控制技术研究

针对遥控水下机器人(ROV:Remote Operated Vehicle)在水下作业时,传统滑膜控制(SMC:Sliding Mode Control)方法存在抖振、稳定性差等问题,提出一种新型协同控制律,并设计出一种基于推力矢量分配的ROV姿态控制器。首先,建立ROV运动学和动力学模型,并解耦动力学模型;然后,提出了一种新型协同控制律,通过构造适当的宏变量使其呈指数收敛,从而为ROV姿态控制系统提供连续的控制律,达到消除ROV姿态控制系统抖振的目的;最后,采用新型协同控制律设计出基于推力矢量分配的ROV姿态控制器。通过Matlab/Simulink进行仿真,结果表明,所提出的新型协同控制律可提高ROV姿态控制系统的控制精度与稳定性。该控制策略为ROV姿态控制提供了一种新的可行方案。