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1.
In this paper, the nonminimum phase problem of a flexible hypersonic vehicle is investigated. The main challenge of nonminimum phase is the prevention of dynamic inversion methods to nonlinear control design. To solve this problem, we make research on the relationship between nonminimum phase and backstepping control, finding that a stable nonlinear controller can be obtained by changing the control loop on the basis of backstepping control. By extending the control loop to cover the internal dynamics in it, the internal states are directly controlled by the inputs and simultaneously serve as virtual control for the external states, making it possible to guarantee output tracking as well as internal stability. Then, based on the extended control loop, a simplified control-oriented model is developed to enable the applicability of adaptive backstepping method. It simplifies the design process and releases some limitations caused by direct use of the no simplified control-oriented model. Next, under proper assumptions, asymptotic stability is proved for constant commands, while bounded stability is proved for varying commands. The proposed method is compared with approximate backstepping control and dynamic surface control and is shown to have superior tracking accuracy as well as robustness from the simulation results. This paper may also provide a beneficial guidance for control design of other complex systems. 相似文献
2.
This paper addresses the nonlinear robust tracking controller design problem for hypersonic vehicles. This problem is challenging due to strong coupling between the aerodynamics and the propulsion system, and the uncertainties involved in the vehicle dynamics including parametric uncertainties, unmodeled model uncertainties, and external disturbances. By utilizing the feedback linearization technique, a linear tracking error system is established with prescribed references. For the linear model, a robust controller is proposed based on the signal compensation theory to guarantee that the tracking error dynamics is robustly stable. Numerical simulation results are given to show the advantages of the proposed nonlinear robust control method, compared to the robust loop-shaping control approach. 相似文献
3.
This paper proposes a fixed-time backstepping control scheme based on fixed-time disturbance observer for flexible air-breathing hypersonic vehicles. The backstepping control is combined with the fixed-time control technique to achieve fixed-time convergence. A fixed-time super-twisting disturbance observer, which is convergent independently of initial conditions, is employed to estimate and compensate the uncertainties and flexible effects in tracking process. A nonlinear first-order filter is adopted to avoid the “explosion of complexity” problem that arises in traditional backstepping, and to guarantee overall fixed-time stability. The closed-loop system is proven to be semi-globally uniformly ultimately fixed-time bounded via Lyapunov analysis. Simulation results are given to demonstrate the effectiveness of the proposed scheme. 相似文献
4.
The objective of this paper is to control the speed of heavy duty vehicle (HDV) through angular position of throttle valve. Modified internal model control (IMC) schemes with fuzzy supervisor as an adaptive tuning are proposed to control the speed of HDV. Internal model (IM) plays a key role in design of various IMC structures with robust and adaptive features. The motivation to design an IM is to produce nearly stable performance as of the system itself. Clustering algorithm and Hankel approximation based model order reduction techniques are used for the design of suitable IM. The time domain performance specifications such as overshoot, settling time, rise time and integral error performance indices such as the integral of the absolute error and the integral of the square of error are taken into consideration for performance analysis of HDV for various uncertainties. 相似文献
5.
An improved prescribed performance controller is proposed for the longitudinal model of an air-breathing hypersonic vehicle (AHV) subject to uncertain dynamics and input nonlinearity. Different from the traditional non-affine model requiring non-affine functions to be differentiable, this paper utilizes a semi-decomposed non-affine model with non-affine functions being locally semi-bounded and possibly in-differentiable. A new error transformation combined with novel prescribed performance functions is proposed to bypass complex deductions caused by conventional error constraint approaches and circumvent high frequency chattering in control inputs. On the basis of backstepping technique, the improved prescribed performance controller with low structural and computational complexity is designed. The methodology guarantees the altitude and velocity tracking error within transient and steady state performance envelopes and presents excellent robustness against uncertain dynamics and deadzone input nonlinearity. Simulation results demonstrate the efficacy of the proposed method. 相似文献
6.
奔腾智能混合动力电动轿车自适应巡航控制系统 总被引：7，自引：0，他引：7
为了从整车系统控制角度综合解决车辆的安全、节能和环保问题,突破目前新能源车辆领域和智能汽车领域仍各独自开展相关技术研究的限制,提出一种融合新能源汽车和智能汽车各自先进技术的解决方案—智能混合动力电动轿车,并提出融合双模式切换自适应巡航控制、整车状态识别及转矩分配控制和驱/制动系统协调控制的整车自适应巡航分层控制体系。在上层控制中研究基于实时状态反馈的双模式切换2自由度结构模型匹配控制器,解决适应混合动力驱动系统动态特性的自适应巡航期望转矩制定的难题;在中层控制中采用了综合内燃机(Internal combustion engine,ICE)优化曲线、电动机最佳效率特性和电池最佳效率特性的基线式控制策略;在下层控制中提出发动机/驱动电动机的转矩协调控制策略和电动机制动/EVB液压制动的协调控制策略。在此基础上,通过仿真分析和实车试验对分层控制系统进行评价与验证。仿真与试验结果表明,所开发的分层式控制系统确保整车在自适应巡航状态下,不仅可以有效提高整车安全性和降低驾驶强度,而且使整车具有最佳的燃油经济性和排放性能。 相似文献
7.
A new online detection strategy is developed to detect faults in sensors and actuators of unmanned aerial vehicle (UAV) systems. In this design, the weighting parameters of the Neural Network (NN) are updated by using the Extended Kalman Filter (EKF). Online adaptation of these weighting parameters helps to detect abrupt, intermittent, and incipient faults accurately. We apply the proposed fault detection system to a nonlinear dynamic model of the WVU YF-22 unmanned aircraft for its evaluation. The simulation results show that the new method has better performance in comparison with conventional recurrent neural network-based fault detection strategies. 相似文献
8.
9.
基于LuGre模型的自适应摩擦补偿 总被引：9，自引：0，他引：9
为提高开放式伺服系统的动态性能,使其具有良好的适应能力,提出一种基于LuGre模型的自适应摩擦补偿方法.建立开放式伺服系统的动力学模型,并通过LuGre模型来描述系统的摩擦特性.考虑到摩擦模型的参数会随系统变化而发生改变,采用Backstepping方法设计自适应摩擦补偿控制器,并采用Lyapunov定理证明系统的全局渐进稳定性.通过可编程多轴控制器(Programmable multi-axis controller,PMAC)编写伺服算法实现该自适应摩擦补偿方案,并通过试验验证该方案的有效性.试验结果表明:与传统的速度加速前馈补偿相比,该自适应摩擦补偿方案在正弦运动作为输入信号时,其跟踪误差由±40 μn降低到±7 μm.采用该补偿方案能有效地抑制摩擦干扰对伺服系统的不利影响,为提高伺服系统的动态跟踪性能奠定基础. 相似文献
10.
汽车方向预瞄式自适应PD控制算法 总被引：1，自引：1，他引：1
针对汽车动力学强非线性时变特性及驾驶员行为特性,基于预瞄跟随理论提出了汽车方向预瞄式自适应PD控制算法,并结合仿真计算和场地试验论证了算法的可行性和有效性。算法中建立了可近似描述汽车转向动力学特性的一阶线性参考模型,并实时在线地辨识了参考模型传递函数的参数;由此根据理想预瞄跟随器的结构,进行了PD控制器参数的自整定。该控制算法可较为精确地控制汽车跟随预期轨迹,且自适应控制算法的采用也提高了控制系统的鲁棒性和适应性,从而为智能汽车方向控制系统的研究提供了一条可行的研究途径。 相似文献
11.
The problem of simultaneous fault detection and control design for switched systems with two quantized signals is presented in this paper. Dynamic quantizers are employed, respectively, before the output is passed to fault detector, and before the control input is transmitted to the switched system. Taking the quantized errors into account, the robust performance for this kind of system is given. Furthermore, sufficient conditions for the existence of fault detector/controller are presented in the framework of linear matrix inequalities, and fault detector/controller gains and the supremum of quantizer range are derived by a convex optimized method. Finally, two illustrative examples demonstrate the effectiveness of the proposed method. 相似文献
12.
根据多年的工作经验,对电梯制动器的电流的电气控制的数量、独立性及控制要求展开分析,进而能准确地判断电梯的电气控制中的制动器是不是符合标准要求。 相似文献
13.
基于MIT规则的自适应Unscented卡尔曼滤波及其在旋翼飞行机器人容错控制的应用 总被引：4，自引：0，他引：4
提出一种新颖的基于MIT规则的自适应Unscented卡尔曼滤波(Unscented Kalman filter,UKF)算法,用来进行参数以及状态的联合估计.针对旋翼飞行机器人执行器提出一种执行器健康因子(Actuator health coefficients,AHCs)的故障模型结构,应用自适应UKF对AHCs参数进行在线估计,将联合估计的状态以及故障参数引入基于模型的反馈线性化控制结构,组成完整的容错控制系统.提出的自适应UKF算法以及容错控制结构经过中科院沈阳自动化研究所ServoHeli-20旋翼无人智能平台数学模型进行仿真试验验证,效果良好. 相似文献
14.
离合器结合控制是影响混合动力汽车模式切换控制中的动力中断时间与冲击度的主要因素,关键在于如何自动适应离合器在使用过程中存在的磨损及其工作环境条件的变化。为此,提出一种基于数据驱动和转矩预测的在线自适应优化控制方法,通过人工神经网络辨识离合器模型并在线更新,采用卡尔曼滤波方法实时预测离合器转矩,解决离合器参数的动态不确定性问题,进而以综合抑制冲击度和减少结合时间为目标函数,结合组合优化算法得到最优占空比序列和最优结合时间,同时采用发动机目标转速轨迹跟踪控制完成离合器两侧转速同步。测试结果证明,提出的方案可实时应用于车辆在线控制,相比其他控制方法,能有效抑制冲击度和减少结合时间。 相似文献
15.
讨论两种与不同驾驶员转向控制策略相应的人－车才环系统的运动特征。在描述驾驶员操纵汽车时可以认为驾驶员有两种操纵方式，即通过给转向盘施加转向力矩或通过使转盘转地定定角度来实施其转向策略，分别称这两控制方式为力输入控制与角输出控制。仿真计算表明，当不足转向度小的汽车高速行驶时，驾驶员采用力输入控制策略具有更小的跟随误差，在力输入控制下，驾驶员校正参数的变化范围也比采用角输入控制策略的小得多，这说明力输 相似文献
16.
This paper is concerned with the adaptive fault-tolerant control (FTC) problem for a class of multivariable nonlinear systems with external disturbances, modeling errors and time-varying sensor faults. The bias, drift, loss of accuracy and loss of effectiveness faults can be effectively accommodated by this scheme. The dynamic surface control (DSC) technique and adaptive first-order filters are brought together to design an adaptive FTC scheme which can reduce significantly the computational burden and improve further the control performance. The adaptation laws are constructed using novel low-pass filter based modification terms which enable under high learning or modification gains to achieve robust, fast and high-accuracy estimation without incurring undesired high-frequency oscillations. It is proved that all signals in the closed-loop system are uniformly ultimately bounded and the tracking-errors can be made arbitrary close to zero. Simulation results are provided to verify the effectiveness and superiority of the proposed FTC method. 相似文献
17.
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. 相似文献
18.
Jana AK 《ISA transactions》2007,46(1):49-57
A nonlinear adaptive control strategy is proposed for a binary batch distillation column. The hybrid control algorithm comprises a generic model controller (GMC) and a nonlinear adaptive state estimator (ASE). The adaptive observation scheme mainly estimates the imprecisely known parameters based on the available tray temperature measurements. The sensitivity of the proposed estimator is investigated with respect to the effect of initialization error, unmeasured disturbance and uncertainty. Then, a comparative study is carried out between the derived nonlinear GMC-ASE controller and a traditional proportional integral law in terms of set point tracking and disturbance rejection performance. The study also includes the effect of measurement noise and parametric uncertainty on the closed-loop performance. The proposed adaptive control algorithm is shown to be quite promising due to the exponential error convergence capability of the ASE estimator in addition to the high-quality control action provided by the GMC controller. 相似文献
19.
An autonomous entry guidance law is developed based on 3-D analytical glide formulas, where the downrange formula is used to plan the longitudinal reference profile in order to meet the downrange and final energy requirements, and the crossrange formula is used to regulate the bank reversals in order to eliminate the crossrange error. As the analytical glide formulas ignore the effects of the Earth׳s rotation, a series of strategies is proposed for compensating these effects, which provides the guidance with the capability of steering the hypersonic glide vehicle with high Lift to Drag ratio (L/D) to any place of the world accurately. The compensation strategies can be summarized into two parts: (1) the reference profiles are properly adjusted by roughly evaluating the effects of the Earth׳s rotation on the aerodynamic profiles over the whole flight, which can compensate most of the effects; (2) the current effects are accurately evaluated and then the guidance commands are slightly modulated for compensating the remaining effects. Due to careful design, the strategies will not result in drastic changes in the Angle of Attack (AOA) and can keep the bank angle almost constant during most of flight. 相似文献
20.
This paper investigates the flight control problem of generic hypersonic vehicles subject to nonaffine-in-control character. Considering the large uncertainties and external disturbance, the disturbance observer based control strategy is incorporated in the control scheme. Firstly, an extended state observer is used to estimate the system states and the total disturbance. Then, based on the output of the extended state observer, we follow the backstepping design procedure. The dynamic inversion method is involved in the last step of backstepping to solve the nonaffine-in-control problem. The proposed control scheme ensures that the hypersonic vehicle tracks the command signal with almost no aerodynamic knowledge. Rigorous stability proof is given based on the separated time-scale structure of the extended state observer and the dynamic inversion method. At last, numerical simulations are presented in different conditions to demonstrate the effectiveness and good tracking performance of the proposed control scheme. 相似文献