Error analysis and a new steering law design for spacecraft control system using SGCMGs

Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros （SGCMGs） as the actuator for the attitude control system.The expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque error.The method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is designed.Simulation results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities.

Practical Survey on Design and Testing of Flight Control Laws for Helicopter Engineering Simulators

A practical survey on engineering implementation of flight control laws on helicopter engineering simulators is proposed.Advances of helicopter engineering simulators are introduced.Practical flight control technologies are reviewed,with an emphasis on discussing the corresponding engineering simulation programs.Finally,the difficulties of implementing advanced control technologies are addressed,and the future development of helicopter engineering simulators are highlighted.

Remote Control Guidance Law Design Using Variable Structure Control

A method of sliding mode variable structure control for the missile body being a time varying system is presented. A remote control guidance law is designed. The method has strong robustness to target＇ s maneuver. To reduce the chattering phenomena, quasi-sliding mode variable structure control method is used. Simulation results show that the proposed method has small miss distance for any kind of maneuvering targets and requires small control energy.

Improving the Control Energy in Model Reference Adaptive Controllers Using Fractional Adaptive Laws

This paper presents the analysis of the control energy consumed in model reference adaptive control(MRAC)schemes using fractional adaptive laws, through simulation studies. The analysis is focused on the energy spent in the control signal represented by means of the integral of the squared control input(ISI). Also, the behavior of the integral of the squared control error(ISE) is included in the analysis.The orders of the adaptive laws were selected by particle swarm optimization(PSO), using an objective function including the ISI and the ISE, with different weighting factors. The results show that, when ISI index is taken into account in the optimization process to determine the orders of adaptive laws,the resulting values are fractional, indicating that control energy of the scheme might be better managed if fractional adaptive laws are used.

Novel robust control framework for morphing aircraft

This paper develops a robust control methodology for a class of morphing aircraft,which is called innovative control effector（ICE） aircraft.For the ICE morphing aircraft,the distributed arrays of hundreds of shape-change devices are employed to stabilize and maneuver the air vehicle.Because the morphing aircraft have the inherent uncertainty and varying dynamics due to the alteration of their configuration,a desired control performance can not be satisfied with a fixed feedback controller.Therefore,a novel control framework including an adaptive flight control law and an adaptive allocation algorithm is proposed.Firstly,a state feedback adaptive control law is designed to guarantee closed-loop stability and state tracking in the presence of uncertain dynamics caused by the wing shape change due to different flight missions.In the control allocation,many distributed arrays are managed in an optimal way to improve the robustness of the system.The scheme is used to an uncertain morphing aircraft model,and the simulation results demonstrate their performance.

Sliding Mode Variable Structure Control for Visual Servoing System

A visual servoing tracking controller is proposed based on the sliding mode control theory in order to achieve strong robustness against parameter variations and external disturbances. A sliding plane with time delay compensation is presented by the pre-estimate of states. To reduce the chattering of the sliding mode controller, a modified exponential reaching law and hyperbolic tangent function are applied to the design of visual controller and robot joint controller. Simulation results show that the visual servoing control scheme is robust and has good tracking performance.

BOUNDARY CONTROL OF MKDV-BURGERS EQUATION

The boundary control of MKdV-Burgers equation was considered by feedback control on the domain [0,1]. The existence of the solution of MKdV-Burgers equation with the feedback control law was proved. On the base, priori estimates for the solution was given. At last, the existence of the weak solution of MKdV-Burgers equation was proved and the global-exponential and asymptotic stability of the solution of MKdV-Burgers equation was given.

An Adaptive Fuzzy Sliding Mode Control Scheme for Robotic Systems

In this article, an adaptive fuzzy sliding mode control (AFSMC) scheme is derived for robotic systems. In the AFSMC design, the sliding mode control (SMC) concept is combined with fuzzy control strategy to obtain a model-free fuzzy sliding mode control. The equivalent controller has been substituted for by a fuzzy system and the uncertainties are estimated on-line. The approach of the AFSMC has the learning ability to generate the fuzzy control actions and adaptively compensates for the uncertainties. Despite the high nonlinearity and coupling effects, the control input of the proposed control algorithm has been decoupled leading to a simplified control mechanism for robotic systems. Simulations have been carried out on a two link planar robot. Results show the effectiveness of the proposed control system.

Impulsive control of chaotic systems with exogenous perturbations

The impulsive control of chaotic systems, which are subjected to unbounded exogenous perturbations, is considered. By using the theory of impulsive differential equation together with the fuzzy control technique, the authors propose an impulsive robust chaos controlling criterion expressed as linear matrix inequalities （LMIs）. Based on the proposed control criterion, the procedure for designing impulsive controllers of common （perturbed） chaotic systems is provided. Finally, a numerical example is given to demonstrate the obtained theoretical result.

Adaptive Sliding-Mode Control of an Automotive Electronic Throttle in the Presence of Input Saturation Constraint

In modern vehicles, electronic throttle(ET) has been widely utilized to control the airflow into gasoline engine. To solve the control difficulties with an ET, such as strong nonlinearity,unknown model parameters and input saturation constraints,an adaptive sliding-mode tracking control strategy for an ET is presented. Compared with the existing control strategies for an ET, input saturation constraints and parameter uncertainties are adequately considered in the proposed control strategy. At first, the nonlinear dynamic model for control of an ET is described. According to the dynamical model, the nonlinear adaptive sliding-mode tracking control method is presented,where parameter adaptive laws and auxiliary design system are employed. Parameter adaptive law is given to estimate the unknown parameter with an ET. An auxiliary system is designed,and its state is utilized in the tracking control method to handle the input saturation. Stability proof and analysis of the adaptive sliding-mode control method is performed by using Lyapunov stability theory. Finally, the reliability and feasibility of the proposed control strategy are evaluated by computer simulation.Simulation research shows that the proposed sliding-mode control strategy can provide good control performance for an ET.

Position Control of Synchronous Motor Drive by Modified Adaptive Two-phase Sliding Mode Controller

A modified adaptive two-phase sliding mode controller for the synchronous motor drive that is highly robust to uncertain- ties and external disturbances is proposed in this paper.The proposed controller uses two-phase sliding mode control (SMC) where the 1st phase mainly controls the system in steady states and disturbed states-it is a smoothing phase.The 2nd phase is used mainly in the case of disturbed states.Also,it is an autotuning phase and uses a simple adaptive algorithm to tune the gain of conventional variable structure control (VSC).The modified controller is useful in position control of a permanent magnet synchronous drive.

An Improved Robust Model Predictive Control Approach to Systems with Linear Fractional Transformation Perturbations

In this paper, a robust model predictive control approach is proposed for a class of uncertain systems with time-varying, linear fractional transformation perturbations. By adopting a sequence of feedback control laws instead of a single one, the control performance can be improved and the region of attraction can be enlarged compared with the existing model predictive control （MPC） approaches. Moreover, a synthesis approach of MPC is developed to achieve high performance with lower on-line computational burden. The effectiveness of the proposed approach is verified by simulation examples.

APPLICATION OF DIRECT BTT GUIDANCE LAW BASED ON NONLINEAR INVERSE SYSTEM THEORY TO INTEGRATED FIRE／FLIGHT SYSTEMS（IFFS）

To counter BTT guidance mode, new relative motion equations of the targetaircraft and the attack aircraft are proposed. The inverse system theory of the nonlinearcontrol is used, and the direct BTT-180 guidance command is solved, which can operatethe attack aircraft to automatically complete the flight mission of the preceding stage ofthe terminal weapon delivery, and thus the automatic attack is extended from the stage ofthe terminal weapon delivery to the preceding stage of the terminal weapon delivery.

基于改进型SM-ADRC的PMSM控制策略研究

在永磁同步电机(PMSM)控制中,传统的滑模自抗扰控制(SM-ADRC)能够减小外部负载变化和参数变化导致控制系统性能下降所带来的影响,但是还存在控制器参数太多,整定过于复杂化的问题,故提出一种改进型SM-ADRC方法。设计了一种新型变指数趋近律及新型控制函数将其引入扩展状态观测器(ESO)和非线性状态误差反馈控制律(NLSEF),得到新型滑模状态观测器(SM-ESO)和新型滑模状态误差反馈控制律(SM-NLSEF),减少了SM-ESO和SM-NLSEF待整定参数个数,简化了SM-ADRC参数整定。建立Simulink仿真模型和Links-RT半实物仿真实验平台,仿真和实验结果均表明:与传统SM-ADRC相比,改进型SM-ADRC在简化参数整定的同时提高了系统的响应速度和系统的抗扰性能,减小了电流脉动。

基于改进分数阶滑模控制的PMLSM直接推力控制

针对分数阶滑模控制在永磁直线同步电机(Permanent Magnet Linear Synchronous Motor, PMLSM)直接推力控制下转速环精度不高、磁链和推力波动大等问题,提出一种改进的分数阶滑模控制算法,即分数阶双幂次指数趋近律、分数阶变速趋近律相结合的组合趋近律,能有效减弱滑模控制引起的系统振荡,加快趋近速率。仿真结果表明:与分数阶滑模控制相比,在PMLSM直接推力控制系统中采取改进分数阶滑模控制,磁链和推力波动明显减弱,系统响应速度加快,提高了PMLSM推力响应的抗干扰能力。

基于PSO的飞行器姿态智能控制技术研究

以气动舵/推力矢量/直接力复合控制飞行器为对象,研究了多维异构复合姿态控制系统的控制律及分配律一体化智能设计问题。首先提出了基于PSO(Particle Swarm Optimization)算法的“智能控制律+智能分配律”飞行器姿态多维异构智能复合控制算法框架,并建立了控制系统数学模型,然后重点研究了控制律及分配律参数的智能优化算法实现方法,最后通过数学仿真验证了提出方法的有效性。仿真结果表明,所设计智能优化复合控制系统在标称模型以及模型摄动情况下均能够实现对姿态角指令的准确快速跟踪。

基于变幂次对数趋近律的振动基机械臂快速鲁棒控制

针对一类安装基座存在不确定随机振动的机械臂系统,提出了一种基于变幂次对数趋近律的快速鲁棒控制策略。基于Euler‐Lagrange方程建立了系统的不确定动力学模型,并将模型中的基座振动项提取出来看作机械臂所受的不确定外部扰动力。提出了一种全新的变幂次对数函数趋近律,既能实现系统状态在远离滑模面时的快速趋近,又能保证在接近滑模面后的抖振能够被有效抑制。在此基础之上,结合一种快速终端滑模面设计了系统的快速鲁棒控制器,进一步提高了系统状态的收敛速度。基于Lyapunov稳定性理论证明了所设计控制器的有限时间收敛特性。搭建了实验平台,通过实验进一步验证所设计控制器的有效性。

基于灰狼算法的步进电机滑模控制系统设计

为了改善转台方位轴的位置精准度及抖振现象,本文围绕步进电机控制系统展开研究。设计了指数趋近律的位置方程,应用了灰狼优化算法整定滑模控制系统的多项参数。在此基础上建立了数学模型,使用MATLAB/Simulink构建了位置三闭环仿真,对系统的位置精准度、抗干扰能力进行分析,并与PID控制系统、传统的滑模控制系统进行了比较。仿真结果表明优化后的控制系统较稳定,响应速度快,抗干扰能力强。最后基于STM32F10ZET6主控芯片搭建了硬件平台,实验证明了优化后的控制策略有效提升了位置精准度,保证了系统的可靠性。

中型无人直升机向心回转机动飞行控制律设计

向心回转是直升机的一个标准机动飞行科目,其可以综合检验直升机各通道的控制性能。针对中型无人直升机向心回转机动中姿态控制和速度控制的问题,提出一种增强飞行过程中稳定性和快速性的控制律设计方法。首先,根据ADS-3E-PRF,设计了向心回转机动的控制指令。随后,在内外环串联的通道控制结构基础上,通过推导得出直升机滑模控制律,从而设计姿态内回路的滑模控制器,对比PID控制器得到了更好的姿态增稳效果和更快的响应速度。最后,通过半物理仿真系统的仿真实验,结合向心回转机动的指标,验证了所设计的方法能有效完成向心回转机动,并达到了满意的标准。

混合遗传算法下欠驱动船舶航向保持控制方法

欠驱动船舶容易受到风、浪、洋流等外部环境因素的影响,导致航向偏离、船体摇晃,航行安全风险增加,为提高其在各种海况下的稳定性和安全性,提出混合遗传算法下欠驱动船舶航向保持控制方法。构建欠驱动船舶数学模型描述其动态行为,设计包含跟踪微分器和分数阶滑膜控制器的航行保持控制器,生成期望航向的平滑过渡过程,为后者提供航向角速度和角加速度信号。以航向误差作为其输入控制量,通过设计的分数阶滑膜面和控制律实现期望航向追踪,采用混合遗传算法优化控制器参数,提高航向跟踪效果。实验结果表明:该方法可实现不同海况下船舶航向保持控制,控制效率高、航向控制超调量小。