Study on Modeling and Control Strategy for Electric Drive Motor of Tracked Vehicles

Aimed at the requirements for electric transmission system of a military tracked vehicle, the motor’s design indexes were analysed and calculated. A model based on saturate inductance parameter of interior permanent magnet (IPM) synchronous motor was brought forward by using finite element analysis. And its control strategy based on the largest running capability was studied also. The experiment results for a scale model show that the modelling method improves the model’s accuracy, and the motor’s control strategy is effective.     

A Study on Missile Reentry Control Based on the Method of Feedback Linearization

In the process of missile large attack angle reentry, there exist nonlinear, strong coupling uncertainty and muhiinput-multi-output （MIMO） in the movement equations, so the traditional small disturbance faces difficulties. For such situations, the method of feedback linearization is adopted to control the complex system, and the control method based on the fuzzy adaptive nonlinear dynamic inversion decoupling control of missile is proposed in the paper. According to the principle of time-scale separation, the system is separated into fast loop and slow loop, the method of dynamic inversion is applied to them, and the method of adaptive fuzzy approach is adopted to compensate for the uncertainty of the fast loop. The simulation results denote the. control method in the paper has a better tracing characteristic and robustness.     

Indirect robust control of agile missile via Theta-D technique

An agile missile with tail fins and pulse thrusters has continuous and discontinuous control inputs. This brings certain difficulty to the autopilot design and stability analysis. Indirect robust control via Theta-D technique is employed to handle this problem. An acceleration tracking system is formulated based on the nonlinear dynamics of agile missile. Considering the dynamics of actuators, there is an error between actual input and computed input. A robust control problem is formed by treating the error as input uncertainty. The robust control is equivalent to a nonlinear quadratic optimal control of the nominal system with a modified performance index including uncertainty bound. Theta-D technique is applied to solve the nonlinear optimal control problem to obtain the final control law. Numerical results show the effectiveness and robustness of the proposed strategy. Copyright . 2014, China Ordnance Society. Production and hosting by Elsevier B.V. All rights reserved.     

Research on Electro Hydraulic Proportional Control for Heavy Vehicle Blend Braking System

A blend braking system of heavy vehicle was proposed. The main control part of the system is the electro hydraulic proportional servo valve. A nonlinear model of brake cylinder controlled by the valve was deduced through the analysis of its control property and system feature. The transfer function of the system was also proposed, and the hydraulic inherent frequency and the PID closed-loop system feature were calculated. The simulated result is consistent with those tested in the bench and on the site with 50 t heavy vehicle. The experimental result shows that the control method has quick response and high precision.     

Design of Neural Network Variable Structure Reentry Control System for Reusable Launch Vehicle

A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts：variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.     

Attitude Control Algorithm for Reusable Launch Vehicle in Reentry Flight Phase

An attitude control algorithm for reusable launch vehicle （RLV） in reentry phase is proposed based on sliding mode variable structure control technique. The aerodynamic characteristics of RLV vary rapidly, and the serious uncertainties and nonlinearities exist in the reentry flight phase. As an example, American X-34 technology demonstrator is investigated. The chattering brought by the variable structure control technique is eliminated efficiently by choosing a suitable reaching law and a sign function. A control mode of reaction control system is presented based on the RCS scheme of X-34 vehicle. As two different attitude control effectors, aerosurfaces and RCS, are employed in the reentry flight phase, a composite control strategy based on the dynamic pressure variety is presented. Also, an actuator model and a RCS thruster model are built. Analysis and nonlinear simulation results show that the sliding mode variable structure controller achieves better performance, the overshoot and steady-state error are only 0.7% and 0.04° respectively.     

Guidance Law Design Under Impact Angle Constraint Based on Nussbaum-type Gain Technique

Aiming at the guidance problem under impact angle constraint for homing missile against ground targets,a new adaptive robust nonlinear terminal guidance law was proposed in this paper.According to nonlinear kinetic relationship between the missile and target in vertical plane,a mathematic model was formulated while the motion of target and the system structure perturbation were regarded as limited disturbances.Based on the ideas of zeroing the rate of line-of-sight(LOS)angle and the impact angular tracking error,a nonlinear control strategy was contrived to obtain adaptive robust guidance law by adopting Nussbaum-type gain technique under a desired impact angle.The stability of guidance system in finite time is strictly proven by using Lyapunov stability theory.Finally,the numerical simulation verifies the effectiveness of the proposed scheme.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Research on Airborne Electro-Optical Tracking and Sighting System Based on Fuzzy PID and H∞ Control

Airborne electro-optical tracking and sighting system is a three-degree-of-freedom angular position servo system which is influenced by multi-disturbance, and its control system consists of stabilizing and tracking components. Stabilizing control is applied to track angular velocity order and control multi-disturbance under airborne condition, and its robustness should be very good; tracking control is applied to compensate tracking error of angular position. A mathematical model is established by taking the control of yaw loop as example. H∞ stabilizing controller is designed by taking the advantage of H∞ control robustness and combining with Kalman filter. A fuzzy control is introduced in general PID control to design a decoupled fuzzy Smith estimating PID controller for tracking control. Simulation research shows that the control effect of airborne electro-optical tracking and sighting system based on fuzzy PID and H∞ control is good, especially when the model parameters change and the multi-disturbance exists, the system capability has little fall, but this system still can effectively track a target.     

Satisfactory PI-P Controller Design for High-order Servo System

The paper presents an output feedback controller design method for high-order servo system with the constraints of multiple indices by using satisfactory control theory. The control strategy is to convert transfer-function form of two-loop servo system into state-space form and assign the system poles in the specified region and H∞ attenuation degree in the given range with the Riccati matrix inequality so that the closed-loop system has good dynamics and robust quality. A numeric example is given to show the effectiveness of the proposed approach.     

两个非线性系统Hopf分岔的状态反馈控制

本文简单介绍了Hopf分岔理论,对于Van der pol振子和一个发生亚临界Hopf分岔的二阶非线性系统分别设计了具有可变增益的状态反馈控制器,利用Lyapunov稳定性定理证明了在该控制器作用下,可以消除非线性系统的Hopf分岔现象,保证系统的渐近稳定,控制器与系统参数的变化范围无关,数值仿真也表明了这种控制方法的有效性.因此,对于发生Hopf分岔的非线性系统,可以通过设计合适的状态反馈控制器去消除 Hopf分岔,维持系统的渐近稳定,而不仅是延迟分岔的出现,扩大系统稳定运行的范围.     

一类电机系统的分岔分析与 Hopf 分岔控制

针对无刷直流电机系统等效非线性动力系统,运用中心流形理论和Hopf 分岔理论研究了系统存在的分岔行为,并设计状态反馈控制器对系统进行Hopf 分岔控制,分析了控制参数对 Hopf 分岔点位置、分岔类型以及分岔周期解振幅的影响。研究结果表明:控制器中的线性控制部分能改变原系统的Hopf 分岔点位置,甚至使Hopf 分岔点消失;控制器中的非线性控制部分则可改变原系统的分岔类型及分岔周期解振幅的大小。数值仿真证明控制器设计的有效性。     

弹箭非线性角运动稳定性Hopf分岔分析

为了分析弹箭的角运动稳定性,推导了弹箭的非线性角运动方程组,给出弹箭的非线性角运动Hopf分岔分析方法。以某型火箭弹高原试验为例,选取空气密度作为分岔参数,采用霍尔维茨判据判断了系统的稳定性,并确定了分岔点。由中心流形定理对系统进行降维,计算了Hopf分岔的3阶规范形,并作出了系统的分岔图,分析了分岔参数对极限环摆幅的影响。进行了仿真验证,结果表明,采用分岔分析方法能准确判断系统的稳定性及分析系统的极限环运动。     

鱼雷纵向运动的分叉特性分析

鱼雷运动方程含有诸多的非线性项,用传统的分析方法全面处理非线性问题有一定的难度.运用非线性科学中的分叉理论系统地分析鱼雷运动的稳定性,为探讨求解鱼雷非线性问题,提供了现代分析途径.不需要过于简化的方程,利用等价变换可将高维系统约化到低维的包含了原系统全部动力学特性的中心流形上来研究.通过分叉研究,可以揭示非线性的影响,得到更广义的稳定性结果.     

无人机飞行控制系统非线性设计技术研究

基于现代控制理论的非线性设计是现代无人机飞行控制系统的重要设计方法。在分析总结国内外文献资料的基础上,论述了当前无人机飞行控制系统设计领域中几种重要的非线性设计技术,包括非线性反馈线性化方法、滑模变结构控制方法、多模型自适应控制方法和基于控制Lya- punov函数的Backstepping方法。     

基于二维分岔的超空泡航行体非线性动力学特性分析

基于二维分岔图,利用相轨图、时域仿真图、Lyapunov指数谱等动力学分析工具分析了超空泡航行体复杂的动力学行为,探讨了超空泡航行体运动状态随尾翼偏转角反馈控制增益及空化数的变化规律,确定了航行体稳定运动的条件和参数范围。结果表明:随着参数的变化,超空泡航行体的动力学行为中存在分岔、混沌、周期窗等丰富的非线性物理现象;合理调整尾翼偏转角,能够有效抑制航行体的振荡与冲击。研究结果对超空泡航行体控制器的设计具有重要的指导意义。     

姿控导弹非线性稳定性的分叉分析

应用分叉理论研究了某姿控导弹非线性动力学系统的全局稳定性,给出了导弹动力学系统的数学模型,对导弹开环和闭环纵向稳定性进行了计算分析.沿某典型弹道对该导弹的全局非线性稳定性进行了分析和评估,给出了导弹能够稳定飞行的指令范围和平衡点及其稳定性随姿控指令的变化.研究结果表明,导弹闭环系统的稳定性是令人满意的,但在低空姿态角对舵偏角过于敏感,可能导致飞行中出现小幅振荡现象.     

飞行器倾斜转弯的非线性鲁棒控制

利用自适应控制中回代设计的思想,结合基于微分几何的非线性化反馈线性化方法,研究了一类非线性不确定性系统的鲁棒控制器设计方法,得到了带系统不确定性补偿项的控制规律,并证明了闭环系统的一致肋介稳定性不对一类飞行器的非线性运动模型进行了适当的处理,设计了倾斜转弯运动的非线性鲁棒控制器,并进行了闭环仿真计算,结果表明,控制器对系统不确定性的抑制效果良好。     

滚动轴承内圈局部故障碰撞的Neimark-Sacker分岔研究

本文以滚动轴承内圈局部故障为研究对象,建立三自由度分段非线性故障碰撞模型,通过在故障缺陷的碰撞面处建立Poincaré映射,研究当故障系统随频率增加时,由于滚动体与内圈缺陷的碰撞冲击而出现的Neimark-Sacker分岔等非线性行为,有助于揭示故障碰撞机理,为设备的减振降噪提供理论依据.     

具有间隙非线性的全动舵系统的颤振分析

研究了超声速来流中含间隙舵系统的颤振问题。通过建立舵机传动机构的动力学方程并采用翼段模型和活塞理论,导出了俯仰方向含有间隙的舵面的非线性气动弹性动力学方程,利用 Hopf 分叉理论计算了舵面的颤振速度,并采用描述函数法分析了含间隙舵面的气动弹性响应。在此基础上,研究了传动机构的动态特性和间隙对舵面的颤振速度和极限环振荡行为的影响。研究表明：舵机静刚度较低时,需要考虑其动刚度对颤振速度的影响;仅当间隙内的俯仰刚度较小时,舵面的气弹响应才会发生亚临界 Hopf 分叉;在飞行速度一定的情况下,间隙量增大1倍,极限环振荡的振幅近似增加1倍。