基于故障在线估计的欠驱动机械臂容错控制方法

为了提高机器人机械臂故障曲线跟踪准确性,本文设计了基于故障在线估计的欠驱动机械臂容错控制方法。分析机器人欠驱动机械臂关节故障原理,建立动力学模型实现对关节故障的检测。采用分散控制的思想将机器人欠驱动机械臂容错控制分为故障检测、信号重构、取代控制以及反馈控制四个部分,依据这四部分设计容错控制律,实现对速度信号与错误信息的实时反馈。在此基础上,通过干扰观测器实现控制律的干扰补偿,使容错控制后的机器人欠驱动机械臂具有抗外界干扰能力,以此完成控制方法设计。分析实验结果可知,所提方法不仅提高了故障曲线跟踪的准确性,减少了欠驱动机械臂容错控制后的稳态时间,满足了机器人欠驱动机械臂容错控制设计需求。     

无轴承异步电机传感器故障容错控制

为了避免转速和电流传感器故障对无轴承异步电机(BAM)矢量控制系统中转速环、电流环以及悬浮控制的影响,提出了一种无轴承异步电机传感器故障容错控制策略.首先,设计扩张观测器实现对无轴承异步电机转速及误差的观测,利用数据融合策略来实现故障时转速的平滑切换,再根据转速观测误差设计合理阈值实现速度传感器的故障诊断及容错.其次,...     

非线性系统的集成故障诊断和容错控制

基于解析模型而建立的状态观测法是一种得到了广泛应用的故障诊断和容错控制方法,而该方法在非线性不确定系统中的实际应用却由于未知输入扰动的影响受到一定的局限.针对机电系统中常见的严格反馈型不确定非线性系统,并考虑含有未知输入扰动,提出一种集成故障诊断与容错控制的设计方案,使系统在对不确定模型具有鲁棒性的同时,对执行器故障具有较强的跟踪性.该方案给出一种基于滑模变结构的容错控制器设计方法,并利用滑模变结构中的等值控制方法设计状态观测器,利用自适应方法实现对不同形式故障的重构.将所提方法以电液伺服系统为例进行仿真分析.仿真结果表明,系统对不确定模型具有鲁棒性,对突变、缓变和间歇变化等3种常见形式的故障以及带噪声的缓变故障均可进行较好的重构.     

基于降维观测器的系统最优容错控制

针对含有传感器故障的线性连续系统,利用Riccati矩阵方程设计了故障情况下的动态最优容错控制律,并设计了能同时检测出系统状态和故障状态的增广的降维故障检测器,从而实现了系统的故障检测和容错控制并能满足二次型性能指标.仿真实例验证了这种方法简单有效.     

执行器饱和约束下机器人手臂的最优容错控制

为了提高机器人手臂系统在饱和约束和电机故障下的控制精度,提出了一种最优容错控制策略。首先建立了机器人手臂故障模型,然后设计了故障观测器对故障值进行估计,并提出包含电机故障与饱和约束的性能指标,最终利用神经网络准确估计出性能指标,从而得到了最优容错控制策略。MATLAB环境下仿真结果表明,所设计的最优容错控制策略与自适应容错控制方法相比具有更优的控制效果,能够在0.2 s内稳定跟踪指令信号,最大跟踪误差仅为0.9°,同时输出力矩始终满足饱和约束要求,所设计的故障观测器能够在0.2 s内准确估计出故障值,最大估计误差仅为0.2 N·m,大幅提高了机器人手臂系统的控制精度。     

风能转换系统的故障诊断与主动容错控制

建立了风能转换系统传动部分的故障数学模型,并且在未知干扰情况下构造了自适应故障观测器,用以检测风能转换系统传动部分的故障,并对该故障进行自适应估计。设计了主动容错控制器来保证发生故障时风能转换系统传动部分的稳定性以及可靠运行,并给出各部分详细的稳定性证明。通过对主传动链不同故障类型的仿真,表明了自适应故障诊断及主动容错控制方法的有效性和可行性。     

1/4车辆电磁混合主动悬架容错控制

为了解决电磁混合主动悬架在发生故障时导致的系统失稳现象,设计了一种多模式切换容错控制策略.分别建立了1/4车辆二自由度悬架模型、直线电机数学模型及电磁阀减振器多项式模型.采用未知输入观测器对悬架状态进行估计,以悬架系统簧载质量加速度为正常状态切换条件,以簧载质量加速度残差和稳定模块为故障状态切换条件,设计了一种多模式切...     

基于故障补偿的高速列车主动悬架主动容错控制

针对高速列车主动悬架作动器故障对列车运行稳定性和乘坐舒适性的影响,提出了一种基于故障补偿的高速列车主动悬架主动容错控制方法。建立了1/4车体横向二自由度高速列车主动悬架模型及作动器故障模型,设计鲁棒H_∞输出反馈控制器作为高速列车主动悬架的常规控制器。基于自适应观测器设计高速列车主动悬架作动器在线故障估计器,并以故障估计结果作为输入设计故障补偿器,补偿高速列车主动悬架作动器故障带来的作动力损失,由常规控制器和故障补偿器共同作用实现高速列车主动悬架主动容错控制。采用Matlab/Simulink软件进行仿真,结果表明,基于自适应观测器的在线故障估计器可有效估计作动器常见故障的真实值大小,且故障估计的误差较小,并在基于故障补偿的高速列车主动悬架主动容错控制下,使高速列车故障悬架性能在短暂时滞后恢复至与正常悬架性能相接近的水平。     

考虑传感器与执行器故障的EPS主动容错控制

针对传感器及执行器故障对EPS助力性能的影响,提出一种EPS主动容错控制方法。建立含参数不确定性、传感器与执行器故障的EPS系统模型,将系统不确定性转化为故障估计误差系统的扰动,基于未知输入观测器及线性矩阵不等式推导故障估计误差系统稳定并对扰动具有鲁棒性的充分条件,采用LMI区域极点配置法提升故障估计性能;在此基础上,针对执行器故障设计控制律补偿容错控制算法,针对传感器故障设计信号重构容错控制算法。Matlab/Simulink环境下的仿真结果表明,当传感器与执行器单独或同时发生故障时,设计的故障估计算法均可较为准确地估计故障幅值,故障估计的误差较小;针对不同故障对助力性能的影响,提出的容错控制方法均可使故障EPS系统的助力性能有所恢复。基于LabVIEW PXI的硬件在环试验进一步验证容错控制应用于EPS系统的有效性,提升汽车转向行驶的安全性及可靠性。     

冗余度机器人容错控制研究

对冗余度机器人运动学动力学容错控制进行了较深入的研究,以冗余度机器人容错控制是冗余特性的具体应用这一思想为出发点,利用自运动变量这种冗余参数作为容错控制系统的状态变量,对容错控制系统进行简化,并提出了利用自运动控制冗余度机器人实现各种容错的新方法。仿真结果表明这些方法具有运算简单、容错效果好的优点。     

Anti-disturbance backstepping control for air-breathing hypersonic vehicles based on extended state observer

In this paper, we propose an anti-disturbance backstepping control approach with extended state observer (ESO) for tracking control of air-breathing hypersonic vehicles. Considering the large uncertainties, the external disturbances, and especially the lack of aerodynamic knowledge, several ESOs are introduced in the backstepping controller. With the total disturbance estimation ability of ESOs, almost no aerodynamic knowledge is needed for the controller design. Meanwhile, ESOs are also used to estimate the derivatives of the virtual control signals. The problem of “explosion of terms” is avoided. A key strategy of the controller is that each step of backstepping is activated successively. Consequently, the closed-loop system has time-scale structure. Rigorous stability proof can be obtained. At last, compared simulation results verify the superior tracking performance of the proposed controller.     

Distributed fault-tolerant model predictive control for intermittent fault: A cooperative way

For intermittent actuator faults of large-scale system, a cooperative distributed fault-tolerant model predictive control (DFTMPC) is presented. The actuator plug and play strategy is adopted in the interconnected systems with physical coupling making fault estimation and controller redesign unnecessary. The actuator plug and play process is modeled as a distributed switching model, and there a theoretical stability analysis is provided with switching form of model predictive control (MPC) cost functions. The novel cooperative distributed fault-tolerant performance index is raised in a global view for distributed model predictive control. A simulation example is taken to show the e?ectiveness of the proposed method.     

Anti-disturbance dynamic surface control scheme for a class of uncertain nonlinear systems with asymmetric dead-zone nonlinearity

This study proposes anti-disturbance dynamic surface control scheme for nonlinear strict-feedback systems subjected simultaneously to unknown asymmetric dead-zone nonlinearity, unmatched external disturbance and uncertain nonlinear dynamics. Radial basis function-neural network (RBF-NN) is invoked to approximate the uncertain dynamics of the system, and the dead-zone nonlinearity is represented as a time-varying system with a bounded disturbance. The nonlinear disturbance observer (NDO) is proposed to estimate the unmatched external disturbance which further will be used to compensate the effect of the disturbance. Then, by integrating RBF-NN, NDO and dynamic surface control (DSC) approaches, the proposed anti-disturbance control scheme is designed. Stability analysis of the closed-loop system shows that all signals of the closed-loop system are semi-globally uniformly ultimately bounded and the tracking error can be made arbitrarily small by proper selection of the design parameters. In comparison with the existing methods, the proposed scheme deals with the unmatched external disturbance, uncertain dynamics and unknown asymmetric dead-zone nonlinearity, simultaneously; it avoids the "explosion of complexity" problem and develops the simple control law without singularity concern. Furthermore, some imposed assumptions to the dead-zone input and disturbances are relaxed. Simulation and comparison results verify the effectiveness of the proposed approach.     

基于时延估计技术的漂浮基空间机械臂容错控制

讨论了具有未知参数的漂浮基空间机械臂在发生电机故障时的动力学建模、运动容错控制算法问题。利用Lagrange第二类动力学方程建立了系统在发生故障时的动力学模型。针对该模型,提出了一种基于Backstepping思想与时延估计技术相结合的容错控制方法,并证明了整个闭环控制系统的渐进稳定性。提出的混合控制方法能够有效地解决漂浮基空间机械臂参数不确定及电机故障问题。通过计算机数值仿真,验证了上述控制方案的有效性和可行性。     

Reduced-order observer based fault estimation and fault-tolerant control for switched stochastic systems with actuator and sensor faults

This paper addresses the problems of fault estimation and fault-tolerant control for a class of switched stochastic systems with sensor and actuator faults. A reduced-order fault estimation observer is designed to estimate the system states, actuator and sensor faults, simultaneously. In the observer design process, intermediate variables are introduced such that the differential information of the measurement output is not included in the designed observer. Compared with the existing results, the dimension of the proposed observer is reduced, and the sensor fault can be completely unknown and unbounded. An observer based fault-tolerant controller is designed to stabilize the switched stochastic systems. Under arbitrary switching signal, the designed observer and controller can ensure that both the estimation error system and the closed-loop system are mean-square exponentially stable with disturbance attenuation performance. At last, both a numerical example and a switched electrical circuit example verify the proposed method.     

基于容错技术的过程控制系统的可靠性研究

对过程控制中的容错技术进行了研究,介绍了容错过程控制的基本思想,从控制系统的硬件和软件2个方面,分析,利用容错技术提高控制系统的可靠性的措施和方法,最后深度挖掘了容错设计中的关键技术。研究结果表明,容错技术可有效地保障过程控制系统的安全性和可靠性。     

Rule-based fault diagnosis of hall sensors and fault-tolerant control of PMSM

Hall sensor is widely used for estimating rotor phase of permanent magnet synchronous motor(PMSM). And rotor position is an essential parameter of PMSM control algorithm, hence it is very dangerous if Hall senor faults occur. But there is scarcely any research focusing on fault diagnosis and fault-tolerant control of Hall sensor used in PMSM. From this standpoint, the Hall sensor faults which may occur during the PMSM operating are theoretically analyzed. According to the analysis results, the fault diagnosis algorithm of Hall sensor, which is based on three rules, is proposed to classify the fault phenomena accurately. The rotor phase estimation algorithms, based on one or two Hall sensor(s), are initialized to engender the fault-tolerant control algorithm. The fault diagnosis algorithm can detect 60 Hall fault phenomena in total as well as all detections can be fulfilled in 1/138 rotor rotation period. The fault-tolerant control algorithm can achieve a smooth torque production which means the same control effect as normal control mode (with three Hall sensors). Finally, the PMSM bench test verifies the accuracy and rapidity of fault diagnosis and fault-tolerant control strategies. The fault diagnosis algorithm can detect all Hall sensor faults promptly and fault-tolerant control algorithm allows the PMSM to face failure conditions of one or two Hall sensor(s). In addition, the transitions between health-control and fault-tolerant control conditions are smooth without any additional noise and harshness. Proposed algorithms can deal with the Hall sensor faults of PMSM in real applications, and can be provided to realize the fault diagnosis and fault-tolerant control of PMSM.     

Dual-quaternion based fault-tolerant control for spacecraft formation flying with finite-time convergence

Study results of developing control system for spacecraft formation proximity operations between a target and a chaser are presented. In particular, a coupled model using dual quaternion is employed to describe the proximity problem of spacecraft formation, and a nonlinear adaptive fault-tolerant feedback control law is developed to enable the chaser spacecraft to track the position and attitude of the target even though its actuator occurs fault. Multiple-task capability of the proposed control system is further demonstrated in the presence of disturbances and parametric uncertainties as well. In addition, the practical finite-time stability feature of the closed-loop system is guaranteed theoretically under the designed control law. Numerical simulation of the proposed method is presented to demonstrate the advantages with respect to interference suppression, fast tracking, fault tolerant and practical finite-time stability.     

基于反馈线性化和保性能控制的轴向磁轴承单侧线圈故障容错控制

针对轴向永磁偏置磁轴承一侧线圈无电流时磁轴承承载能力下降且非线性增强的情况,提出一种反馈线性化与保性能控制相结合的组合容错控制策略来提高轴向磁轴承在故障情况下的承载能力并使其能在承重时稳定悬浮转子。首先,建立了故障情况下后轴向磁轴承-转子系统的非线性动力学模型,通过反馈线性化方法使系统大范围线性化。然后,在考虑参数摄动的基础上设计最优保性能控制器使转子稳定悬浮。最后,在轴向一侧线圈无电流的永磁偏置磁悬浮转子上进行了多项实验。实验结果表明,所设计的组合容错控制器实现了承重情况下转子的稳定悬浮,摄动最大的参数变化约35%时位移跳动量峰值为2.6μm,超调量小于3%,调节时间为82ms。结果验证了该方法不仅能实现容错控制,而且具有良好的动静态性能及鲁棒性。