空空导弹投放信号中断故障容错设计与PHM实现

载机送出投放信号启动空空导弹弹射过程,当该过程尚未结束而投放信号中断或瞬断时,则会产生机-弹分离安全性问题.为了防止该问题的发生,在弹射控制电路的基础上,采用高能复合钽电解电容储存电能的方法实现投放信号中断故障容错.在电容充电过程中,通过在线测试充电电压得到实际电容充电曲线,比较该曲线和标准曲线的均方误差进行故障预测和健康管理.试验表明了故障容错设计和故障预测的可行性和有效性.     

基于分支分析的机翼摇晃预测与抑制

针对现代战斗机大迎角飞行时的机翼摇晃预测与抑制问题,根据其主要动态特性建立了新的横侧向多自由度模型,通过开环分支分析准确预测了机翼摇晃对应的临界迎角.在此基础上考虑模型不确定性和舵面位置限幅的影响,利用滤波器动态对跟踪误差进行补偿,设计了一种约束滤波自适应反步控制算法,通过采用补偿误差代替跟踪误差进行自适应律设计,确保了输入饱和条件下自适应过程的稳定,并结合闭环分支分析实现了对机翼摇晃运动的有效抑制.六自由度仿真验证了多自由度模型的有效性和控制算法的鲁棒性.     

欠驱动飞艇三维路径跟踪控制

针对欠驱动飞艇的路径跟踪控制问题,提出了一种基于制导向量场的三维路径跟踪控制方法.首先,引入向量场理论.接着基于牛顿–欧拉方程建立欠驱动飞艇动力学模型.基于所提模型和向量场理论构造制导向量场以获得期望姿态角和期望速度.然后结合反步法和PD控制设计路径跟踪控制器,用指令滤波器对控制器设计过程中虚拟控制的导数进行估计,避免了复杂的解析计算.所设计的控制器是由制导向量场子系统、姿态稳定环和速度跟踪环组成的内外环结构.稳定性分析证明了飞艇的路径跟踪误差最终一致有界.最后仿真结果验证了所提出方法的有效性.     

输出受限迟滞非线性系统的反步控制器设计

针对一类含有Bouc-Wen迟滞的输出受限非线性系统设计了反步控制器.首先分析了Bouc-Wen模型的特性并得到其上界值,然后设计了对称型障碍Lyapunov函数(barrier Lyapunov function,BLF),保证了BLF有界,从而满足了输出受限的条件,最后利用反步法设计控制器.该方法消除了迟滞引起的振荡和超调并且使得系统输出约束在设定的范围内,同时解决了迟滞和系统输出受限两个方面的影响,提高了控制精度.仿真和实验结果表明了控制方法的可行性.     

Adaptive neural control for an uncertain robotic manipulator with joint space constraints

In this paper, adaptive neural tracking control is proposed for a robotic manipulator with uncertainties in both manipulator dynamics and joint actuator dynamics. The manipulator joints are subject to inequality constraints, i.e., the joint angles are required to remain in some compact sets. Integral barrier Lyapunov functionals (iBLFs) are employed to address the joint space constraints directly without performing an additional mapping to the error space. Neural networks (NNs) are utilised to compensate for the unknown robot dynamics and external force. Adapting parameters are developed to estimate the unknown bounds on NN approximations. By the Lyapunov synthesis, the proposed control can guarantee the semi-global uniform ultimate boundedness of the closed-loop system, and the practical tracking of joint reference trajectory is achieved without the violation of predefined joint space constraints. Simulation results are given to validate the effectiveness of the proposed control scheme.     

Second‐order sliding mode controller design subject to mismatched unbounded perturbations

The dynamics of the second‐order sliding mode (SOSM) can be obtained by directly taking the second derivative on the sliding variable when it has a relative degree of 2 with respect to the control input. However, there will always appear some state‐dependent certain or uncertain terms in the first derivative of the sliding variable, and the derivative directly imposed on these terms could enlarge the uncertainties in the control channel. One method to reduce the uncertainties in the control channel is to hold this information in the dynamics of the first derivative of the sliding variable, while the original SOSM dynamics could be transformed to be a SOSM system with a mismatched unbounded perturbation. This paper focuses on the controller design problem for SOSM dynamics subject to mismatched unbounded perturbation. By using Lyapunov analysis, a novel backstepping‐like design methodology will be proposed. The rigorous mathematical proof will show that under the derived SOSM controller, the closed‐loop sliding mode dynamics is globally finite‐time stable. Meanwhile, the frequently used constant upper bound assumptions for the standard SOSM system can also be extended to the state‐dependent hypotheses in this paper. An academic example is illustrated to verify the effectiveness of the proposed method. Copyright © 2017 John Wiley & Sons, Ltd.     

A consensus model for hesitant fuzzy preference relations and its application in water allocation management

This paper investigates a consensus model for hesitant fuzzy preference relations (HFPRs). First, we present a revised definition of HFPRs, in which the values are not ordered for the hesitant fuzzy element. Second, we propose an additive consistency based estimation measure to normalize the HFPRs, based on which, a consensus model is developed. Here, two feedback mechanisms are proposed, namely, interactive mechanism and automatic mechanism, to obtain a solution with desired consistency and consensus levels. In the interactive mechanism, the experts are suggested to give their new preference values in a specific range. If the experts are unwilling to offer their updated preferences, the automatic mechanism could be adopted to carry out the consensus process. Induced ordered weighted averaging (IOWA) operator is used to aggregate the individual HFPRs into a collective one. A score HFPR is proposed for collective HFPR, and then the quantifier-guided dominance degrees of alternatives by using an OWA operator are obtained to rank the alternatives. Finally, both a case of study for water allocation management in Jiangxi Province of China and a comparison with the existing approaches are carried out to show the advantages of the proposed method.     

基于修正变分法开孔板和加强板结构的自由振动分析

为研究船舶开孔板和加强板结构的振动特性,用1阶剪切变形板理论描述各向同性板的位移场,并采用修正变分原理和区域分解方法建立板的离散动力学模型.每一块子域板的位移和转角分量通过第一类切比雪夫正交多项式展开.针对加强板模型,将该方法获得的结果与已经发表的文献和有限元商用软件计算结果进行对比,验证该方法的收敛性和正确性.基于修正变分法探讨多种开孔和加强板模型的自由振动特性,充分说明该数理模型和半解析方法是一种适合处理复杂板结构问题的数值工具.     

Adaptive dynamic surface control for uncertain nonaffine nonlinear systems

This paper focuses on the problem of adaptive control for uncertain nonaffine nonlinear systems. The original nonaffine systems are transformed into the augmented affine systems via adding an auxiliary integrator, which makes the explicit control design possible. By introducing a modified sliding mode filter in each step, a novel adaptive dynamic surface controller is proposed, where the ‘explosion of complexity’ problem inherent in the backstepping design is avoided. It is proven rigorously that for any initial control condition, the proposed adaptive scheme is able to ensure the semiglobal uniformly ultimately boundedness of all signals in the closed loop. An illustrative example is carried out to verify the effectiveness of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.     

一类欠驱动系统的非线性输出跟踪控制

针对一类模型结构为非下三角的欠驱动系统,在反步法的框架下研究了其非线性输出跟踪控制问题．鉴于在此类欠驱动系统的反步法设计中,沿用一般下三角系统的偏差难以镇定全部的偏差动态,由此引入了“联系函数”的概念．在反步法设计中,构造了异于下三角系统的偏差,设计了状态反馈跟踪控制器,保证了系统偏差的全局一致渐近稳定性．仿真结果表明...