超机动飞行快回路的自适应模糊滑模控制

针对超机动飞行快回路的不确定非线性模型,提出了一种利用自适应模糊滑模控制器算法。在所得的最终控制信号中,采用模糊逻辑系统来逼近未知系统函数和开关项;所设计的鲁棒自适应律用来减小逼近误差,从而有效降低抖振。仿真结果表明,所设计的控制律能在过失速机动条件下控制飞机跟踪指令飞行,确保系统具有良好的动态和稳态性能,而且控制器具有很强的鲁棒性。     

滑模观测器和比例积分的超机动动态逆控制

研究了一种基于Super-twisting算法的滑模观测器和比例积分的超机动飞机动态逆控制方法。首先分析考虑推力矢量下的超机动飞机非线性特性,建立飞机非线性仿真平台;然后在快回路中针对飞行环境下外部直接干扰力矩,采用Super-twisting算法的滑模观测器估计干扰力矩,设计补偿控制律进行干扰抑制;慢回路中采用经典的比例积分控制弥补由非线性对消引起的系统逆误差;最后对设计的控制律进行大迎角下的"眼镜蛇"机动。仿真结果表明,设计的控制律使超机动飞机具有良好的快速性和稳定性。     

可重构飞行控制系统的滑模自适应控制律设计

当飞行控制系统操纵面发生损伤故障时,结合自适应思想,采用滑模控制方法进行重构飞行控制系统的设计.采用单位向量法设计滑模控制器,这种控制器由线性部分和非线性部分组成.线性部分采用改进的线性二次型最优控制器法进行计算,而非线性部分采用自适应增益来更好地适应故障情况.利用某型飞机的纵向飞行控制系统模型进行仿真,结果表明,带有自适应增益的滑模控制方法不仅适合于正常情况下的飞控系统设计,而且对操纵面损伤故障情况具有较强的适应能力,与固定增益情况相比,具有更好的跟踪效果和重构控制效果.     

滑模控制永磁同步电动机的矢量控制技术

本文为了解决传统PI控制器鲁棒性差、系统抗扰能力弱和动态响应的问题,针对永磁同步电动机矢量控制系统,设计了一阶滑模变结构速度环控制器。分析滑模转速控制器抖振产生的原因和影响,利用饱和函数设计了边界层滑模控制器,削弱了滑模控制器的抖振。搭建了在Matlab/Simulink环境下的仿真模型,并进行了仿真分析。仿真结果表明该控制策略减小了系统的超调与振荡,使系统具有较好的鲁棒性和动、静态性能。     

非线性系统解耦控制理论在飞控中的应用

首先介绍了一种仿射非线性系统的解耦控制方法,然后采用该方法为某机动飞机设计了解耦控制律,最后对所设计的飞机飞行控制系统进行了闭环仿真研究。仿真结果表明,所设计的控制系统具有良好的解耦性能,可以同时完成较精确的纵向和侧向机动,并且系统动静态品质良好。     

进阶式飞行器控制实验项目设计与实现

飞行器控制系统是一个多输入多输出的复杂非线性系统，为使学生掌握相关控制理论，建立系统工程思想，采用进阶式教学方法设计并开展飞行器控制实验项目。从飞行器建模、机载传感器数据获取与处理、控制器设计、飞行实验验证等环节逐层递进，同时采用虚拟仿真与Pixhawk飞控硬件虚实结合的实验手段，进行飞控系统飞行效果的实验验证。     

民用飞机飞控系统传感器故障诊断研究综述

飞控系统中的各类传感器对飞机稳定与操纵起着至关重要的影响,是飞机的重要安全机载设备之一.传统冗余方法具有"安全性高,经济性低"的特点,通过多余度设计来提升系统的安全性给飞机的重量与结构设计、系统综合集成、维修与检测成本都带来了一定的难题.针对民用飞机飞控系统中各类传感器故障,介绍了典型机载飞控传感器的故障模式,以及对故...     

基于RBF神经网络的半主动悬架滑模控制

针对悬架参数的不确定性,提出一种基于径向基函数(RBF)神经网络的滑模控制方法。根据滑模变结构控制理论设计了两自由度半主动悬架系统的滑模控制器,采用极点配置法确定滑模切换面参数,应用比例切换的控制方法和等速趋近率确定控制律,采用RBF神经网络优化算法优化了滑模控制器。运用MATLAB/simulink进行仿真,结果显示,与被动悬架相比,基于RBF神经网络的滑模半主动控制具有良好的控制效果,显著地改善了车辆的行驶平顺性。     

新型混联式输送机构的全局快速终端滑模控制

针对一种新型混联式汽车电泳涂装输送机构,首先采用拉格朗日法建立其动力学模型,据此设计一种全局快速终端滑模控制器,给出该系统理论收敛时间,并用Lyapunov稳定性定理证明其稳定性。通过MATLAB将全局快速终端滑模控制与趋近律滑模控制进行仿真比较,结果表明全局快速终端滑模控制器能提高系统的响应速度、跟踪精度,并具有全局鲁棒性。     

基于观测器的滑模制导律

为考虑拦截导弹控制回路动态,所设计的滑模制导律在实际应用中往往涉及到不可量测的反馈状态变量和不确定性的内部参数等问题。采用自适应控制和观测方法,给出了一种基于观测器的自适应滑模制导律,观测器主要用于实现对系统状态,如视线角速度的高阶导数和有界不确定项,如相对运动速度的高阶导数等的在线估计,从而满足实际情形下的可执行性要求。制导律推导中考虑到了拦截导弹具有一阶机动动态的情形,且该方法也可以推广到具有高阶机动动态下的设计。非线性系统仿真表明,相比于传统的比例导引和滑模制导律,该制导律在足够的机动性能下,不仅可以实现对机动目标的碰撞拦截,且具有较强的机动性能和拦截性能优势,同时仿真结果也表明了所设计的观测器的有效性。     

超音速巡航导弹飞行高度的串级控制与仿真

建立了超音速巡航导弹飞行高度的串级控制系统模型;利用最优参数整定法设计了副回路反馈补偿PD调节器;运用Matlab/Sisotool设计了主回路控制器.仿真结果表明,串级控制能较大程度地提高超音速巡航导弹飞行高度的控制性能.     

Fractional delay compensated discrete-time SMC for networked control system

Time-varying network induced delay in the communication channel severely affects the performance of closed loop network control systems. In this paper, a novel idea of compensating the fractional time varying communication delay in the sliding surface is presented. The fractional time delay in the sensor to controller and controller to actuator channel is approximated using the Thiran approximation technique to design the sliding surface. A discrete-time sliding mode control law is derived using the proposed surface that compensates fractional time delay in sensor to controller and controller to actuator channels for uncertain network control systems. The sufficient condition for closed loop stability of the system is derived using the Lyapunov function. The efficacy of the proposed strategy is supported by the simulation results.     

自适应模糊滑模控制器设计

针对传统滑模控制的抖振问题,利用线性化反馈技术,将模糊自适应和滑模控制相结合,设计一种新型的模糊滑模控制器。通过模糊推理和基于Lyapunov函数的稳定性分析,获得模糊控制规则的自适应律,构成自适应模糊滑模控制器,有效解决了传统滑模控制中,需要确定参数摄动和外部干扰上确界不确定性问题,倒立摆上的运行结果表明该方法的有效性。     

Adaptive incremental sliding mode control for a robot manipulator

An adaptive incremental sliding mode control (AISMC) scheme for a robot manipulator is presented in this paper. Firstly, an incremental backstepping (IBS) controller is designed using time-delay estimation (TDE) to reduce dependence on the mathematical model. After substituting IBS controller into the nonlinear system, a linear system w.r.t. tracking errors is obtained while TDE error is the disturbance. Then, the AISMC scheme, including a nominal controller and an SMC, is developed for the resulted linear system to improve control performance. According to the equivalent control method, the SMC in the AISMC scheme is to handle TDE error. To receive optimal control performance at the sliding manifold, an LQR controller is selected as the nominal controller. The SMC is designed based on positive semi-definite barrier function (PSDBF) since it prevents switching gains from being over/under-estimated, and two practical problems are addressed in this paper: A new PSDBF is designed and conservative (large) setting bounds affecting tracking precision and/or system stability are avoided; An improved PSDBF based SMC is developed where the PSDBF and an adaptive parameter are used simultaneously to regulate switching gains, and the system is still stable when sliding variable occasionally exceeds the predefined vicinity. Moreover, finite-time convergence property of the sliding variable is strictly analyzed. Finally, real-time experiments are conducted to verify the effectiveness of the proposed control method.     

Design of a general purpose 6-DOF haptic interface

A general purpose six degree-of-freedom haptic device is newly designed, which can be used as a general motion commander as well as a force reflector. The structure features the large workspace and easy analysis of a serial structure and the compactness and durability of a parallel structure at the same time. The study analyzed kinematics of the proposed device to obtain the optimal device parameters in terms of kinematics and derived dynamics to form a linear control system through the feedback. In calculating the optimal design factors of the haptic device in terms of kinematics, this study employed the global isotropy index. The proposed structure has high manipulability within the workspace, which is an essential factor for a motion generator. Also the study proposed a force controller featuring an inner nonlinear loop designed to compensate the nonlinear dynamics of the device and an outer linear control loop aimed to compensate un-modeled dynamics and disturbance. For an outer linear controller, the study adopted an LQG/LTR controller that can systematically take into account stability, robustness and frequency characteristics in the design process. The performance of the proposed device was verified with its efficiency through simulation and experiments.     

Trajectory tracking control for a wheel mobile robot on rough and uneven ground

This paper investigates a dual closed-loop trajectory tracking control strategy for a non-holonomic wheeled mobile robot (WMR) with unknown external disturbances caused by rough and uneven ground. Firstly, a novel dynamic model without coupling is established by introducing a direct current motor model with uncertain parameters. Then a linear extended state observer (LESO) is presented to estimate unknown external disturbance of the WMR. And a dynamic controller based on sliding mode control method is provided in an inner loop to ensure exponential convergence of velocity error while compensating for observational error of the LESO. Considering that the robot’s center of mass and geometric center do not overlap, a kinematic controller is designed in an outer loop to make positional error asymptotically stabilized. Finally, experiments are given to verify performance of tracking and disturbance rejection of the WMR.     

An adaptive hierarchical control approach of vehicle handling stability improvement based on Steer-by-Wire Systems

This paper proposes a novel adaptive hierarchical control approach for Steer-by-Wire (SbW) vehicles to improve the handling stability. The high-level stability control scheme contains a variable steering ratio (VSR) strategy based on the adaptive-network-based fuzzy inference system (ANFIS) and an active front steering (AFS) controller designed with the integral sliding mode method by tracking the expected yaw rate, in which the desired front wheel angle is generated to enhance the cornering stability performance. Besides, an adaptive tracking controller (ATC) for the SbW system is designed by using the adaptive sliding mode control method to achieve desired steering performance in the lower level. The proposed adaptive control strategy is validated with different driving circles from ISO standards in simulation tests and hardware-in-the-loop (HiL) experiments. The results demonstrate that the designed control approach improve the vehicle handling stability significantly, even in some extreme driving conditions.     

滑模变结构在AUV航向控制中的应用

针对自主式水下机器人的控制特点,建立了机器人的动力学数学模型。利用运动解耦的方法完成了水下机器人完备控制量的构建。在滑模变结构控制理论的基础上,设计了水下机器人的分布式滑模控制系统,并在Simulink下完成滑模控制器的建模。预先设定了仿真过程中机器人的运动轨迹跟踪,结果表明,滑模控制能有效地控制AUV的航向,对外部扰动具有较强的鲁棒性。     

基于反步滑模控制的TCP网络的主动队列管理

针对TCP网络的拥塞问题,考虑到网络本身存在参数不确定因素和非响应流的干扰,基于反步滑模控制提出了一种主动队列管理算法。在总的不确定的界已知而且不必很小的情况下,设计了一种反步滑模控制器来补偿系统不确定所带来的影响。仿真结果表明,该方法对TCP网络的复杂变化具有较好的鲁棒性和较快的系统响应。