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1.
In the anode of proton exchange membrane (PEM) fuel cells, the measurable outlet pressure is usually different with the actually utilized stack pressure. In this paper, the anode of PEM fuel cells is divided into three segments to reduce the modeling error between these two pressures and the impact of the spatial distribution of pressure, electrochemical reaction, and gas permeation. Specifically, we first model the fuel delivery system with anode recirculation and bleeding in a MIMO nonlinear compact form based on the segmented anode model. Then, a Lyapunov‐based full state feedback controller is proposed based on the developed model to guarantee adequate hydrogen supply and maintain the anode hydrogen at a suitable concentration level. Moreover, a high order sliding mode observer is proposed to estimate the unmeasurable pressure and the partial pressure in the fuel delivery system with known disturbance. Furthermore, an output feedback controller based on the proposed observer is developed with guaranteed stability. Simulation results illustrate the effectiveness of the proposed control and the estimation approaches. 相似文献
2.
Presented is a method of smooth sliding mode control design to provide for an asymptotic second‐order sliding mode on the selected sliding surface. The control law is a nonlinear dynamic feedback that in absence of unknown disturbances provides for an asymptotic second‐order sliding mode. Application of the second‐order disturbance observer in a combination with the proposed continuous control law practically gives the second‐order sliding accuracy in presence of unknown disturbances and discrete‐time control update. The piecewise constant control feedback is “smooth” in the sense that its derivative numerically taken at sampling rate does not contain high frequency components. A numerical example is presented. 相似文献
3.
Pooyan Alinaghi Hosseinabadi Ali Soltani Sharif Abadi Howard Schwartz Hemanshu Pota Saad Mekhilef 《Asian journal of control》2023,25(5):3456-3473
This paper investigates a fixed-time convergence issue using the sliding mode observer-based controller for a class of uncertain nonlinear double integrator systems. This observer-based controller is designed assuming that only the first state measurement is available and there is no information about external disturbances and modeling uncertainties. A new form of sliding mode observer in combination with a sliding mode controller is designed to estimate unmeasured state and unknown disturbances and uncertainties as well as provide the estimated data in the control law. A novel form of sliding surfaces for the robust observer-based controller is proposed for which fixed-time convergence is guaranteed to achieve trajectory tracking. In the proposed fixed-time scheme, the bound on the settling time is user-defined using design parameters regardless of the system's initial conditions. The control law and observer law are designed such that the chattering issue is alleviated in the control signal. The stability analysis of the closed-loop system using the observer-based controller is established via the Lyapunov theory. The validity of the controller design is tested by applying and simulating an example of a robot manipulator in Simulink/MATLAB. The superiority of the proposed method is demonstrated by comparing it with two other methods from the relevant literature. 相似文献
4.
This work focuses on the problem of observer-based robust speed sensorless control of a 3-phase permanent magnet synchronous motor (PMSM). Nonlinear design techniques are employed for designing robust speed controller and observer that are able to withstand the effects of modelling uncertainties and load variations. A new cascaded observer scheme is proposed comprising a continuous sliding mode observer (SMO) and an extended high-gain observer (EHGO). The proposed cascaded observer reduces chattering, exhibits reasonable insensitivity to modelling inaccuracies and is capable of withstanding errors due to the finite boundary layer of continuous SMO. For the robust speed control, an integral sliding mode controller is designed that yields fast and accurate speed tracking performance even in the presence of bounded uncertainties and external disturbances. The complete scheme has been evaluated using simulations and experiments. 相似文献
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This paper is focused on the problem of adaptive sliding mode control design for uncertain neutral‐type stochastic systems under a prescribed H∞ performance. A simplified state observer is put forward to estimate the unknown state variables, which could be properly incorporated for establishing a new linear‐type switching surface and the associated adaptive variable structure controller. By virtue of the adaptive control design, unknown matched perturbation and potential uncertainties can be counteracted, and the system trajectories are guaranteed to reach the predefined switching surface within finite moment in almost surely sense, and performance analysis of the closed‐loop dynamics during the sliding surface is carried out with a specified H∞ performance. At last, two illustrative examples through computer simulations are provided to verify the effectiveness and applicability of the proposed scheme. 相似文献
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针对机器人系统中含有的不确定参数和未知干扰等问题,提出一种基于双滑模观测器和非奇异快速终端滑模控制的复合控制策略.首先,为了估计补偿模型中的不确定参数和外部干扰带来的未知动态,基于机器人系统欧拉-拉格朗日模型构建滑模观测器,以优化机器人系统轨迹跟踪控制性能;然后,针对滑模观测器中存在残差造成的抖振问题,设计辅助滑模观测器,通过将观测误差反馈补偿,抑制观测器在观测扰动时的抖振现象,进一步提高观测精度;接着,为了实现系统抗扰和轨迹跟踪问题,提出有限时间滑模控制器,通过调节滑模控制中的切换增益,可有效地缩短收敛时间,并提高系统的鲁棒性;最后,通过李雅普诺夫稳定性理论证明闭环系统的稳定性,并通过Simulink仿真验证所提出方法的有效性. 相似文献
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ABSTRACTIn this work, the sliding mode control based on the super-twist observer is presented. The parameters of the controller as well as the observer are admitted to be time-varying and depending on available current measurements. In view of that, the considered controller is referred to as an adaptive one. It is shown that the deviations of the generated state estimates from real state values together with a distance of the closed-loop system trajectories to a desired sliding surface reach a μ-zone around the origin in finite time. The application of the suggested controller is illustrated for the orientation of a tethered satellite system in a required position. 相似文献
8.
为了提高永磁同步电机速度和电流跟踪精度等控制性能, 本文提出了一种基于高阶滑模观测器的永磁同步电机无差拍预测电流控制方法. 首先, 将参数变化和外部负载变化视为集总扰动, 建立内置式永磁同步电机的数学模型. 然后, 构造了两个三阶超螺旋滑模观测器来分别估计速度和电流回路中的集总扰动, 并将估计出的扰动前馈到对应的控制器中进行补偿, 以提高系统的鲁棒性和跟踪精度. 此外, 转速环采用了一种改进的滑模趋近律, 以降低控制信号中的抖振和缩短系统状态到达滑模面所需的时间. 最后, 将所设计的方法在内置式永磁同步电机实验平台进行验证, 并与传统的无差拍预测电流控制和指数趋近律滑模速度控制器进行了对比, 实验结果表明了算法的有效性和优越性 相似文献
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This paper focuses on the design of nonlinear robust controller and disturbance observer for the longitudinal dynamics of a hypersonic vehicle (HSV) in the presence of parameter uncertainties and external disturbances. First, by combining terminal sliding mode control (TSMC) and second-order sliding mode control (SOSMC) approach, the secondorder terminal sliding control (2TSMC) is proposed for the velocity and altitude tracking control of the HSV. The 2TSMC possesses the merits of both TSMC and SOSMC, which can provide fast convergence, continuous control law and hightracking precision. Then, in order to increase the robustness of the control system and improve the control performance, the sliding mode disturbance observer (SMDO) is presented. The closed-loop stability is analyzed using the Lyapunov technique. Finally, simulation results illustrate the effectiveness of the proposed method, as well as the improved overall performance over the conventional sliding mode control (SMC). 相似文献
10.
针对风力机系统在最大功率点跟踪(MPPT)阶段易受风速等不确定因素的影响,为了进一步提高风力机的风能捕获效率,本文在滑模控制的基础上提出了一种互补滑模控制方法.首先,建立了含有干扰项的风力机系统的线性化模型,采用广义滑模面与互补滑模面相结合的方法设计了互补滑模控制器,并在理论上证明了此控制方法能够有效保证风力机转速跟踪误差的收敛性,且能提高转速跟踪精度.其次,采用风力机专业仿真软件FAST对美国可再生能源实验室(NREL)的600 kW风力机进行了仿真实验,结果表明本文所提出的控制方法不但能提高风力机的风能捕获效率,而且能有效减小转速跟踪误差.最后,将本文所提方法与现有常见的几种控制方法相比较发现:风力机系统在互补滑模控制策略下,具有更高的风能捕获效率和更小的转速跟踪误差. 相似文献
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In this paper, a novel fault-tolerant attitude tracking control is proposed for a rigid spacecraft with uncertain inertia matrix, actuator faults, actuator misalignment and external disturbances. The uncertainty of the inertial matrix is caused by the rotation of solar panels, payload movement and fuel consumption, and actuator faults, which include partially failed and completely failed actuators. A novel extended state observer is proposed to estimate the total uncertainties and a fast nonsingular terminal sliding-mode control scheme is proposed to get a faster, higher control precision. Strict finite-time convergence and the concrete convergence time are given. Finally, all the states of the closed-loop system are guaranteed to converge to the corresponding region in a finite time by choosing appropriate parameters. Simulation and comparison results further show the effectiveness and advantages of this method. 相似文献
13.
The aim of this paper is to develop state estimation and sliding mode control schemes for the vibration suppression of an underactuated wing aeroelastic system in the presence of a gust load disturbance. Ignoring structural elastic deformation and using the concentrated elastic system (spring) to simulate the overall elastic deformation, this aeroelastic model consists of a straight wing and spring system, describing flap and pitch freedoms. The corresponding dynamic motion equation is established using the Lagrange method, and the gust is modeled as a typical “1‐cosine” gust. The aerodynamic lift and moment on the wing are computed by strip theory. The open loop system exhibits the limit cycle oscillations (LCOs) at a certain freestream velocity. The objective is to design a control system for suppressing the LCOs. For the purpose of control, a single trailing‐edge control surface is used. It is assumed that only the pitch angle is measured and the remaining state variables needed for full state feedback are estimated by the designed observer. Then an integral sliding surface is put forward on the estimation space; a new continuous reaching law is proposed to reduce the chattering phenomena. The finite‐time reachability of the predesigned sliding surface is proved and guaranteed by the designed sliding mode control law. The sufficient condition for the asymptotic stability of the closed‐loop system composed of the sliding mode dynamics and the error dynamical system is derived in terms of linear matrix inequality (LMI). The effectiveness of the proposed strategy is finally demonstrated by simulation results. 相似文献
14.
针对高超声速飞行器非线性和易受干扰影响的特点,提出了带有扩张状态干扰观测器的连续滑模控制方法.在对飞行器非线性模型做线性化处理的基础上,设计了一种连续时间滑模控制器.该控制器在对不确定性和未知动态保持鲁棒性的基础上,消除了传统滑模中存在的抖振现象.对系统中存在的外加干扰,设计了扩张状态干扰观测器.将外加干扰作为系统的一个状态变量被估计出来,再将估计值用作滑模控制器的补偿量,进而达到消除外干扰的目的.在高超声速飞行器巡航飞行状态的基础上进行了仿真.仿真结果表明,所提出的方案能够满足控制要求. 相似文献
15.
In this study, a novel output feedback terminal sliding mode control (TSMC) approach is proposed for a class of second order nonlinear systems in light of the equivalent output injection sliding mode observer (SMO) method and TSMC principle. The SMO method is applied to reconstruct full states in finite time and the non‐singular TSMC algorithm is designed to stabilize system states to equilibrium points in finite time. The corresponding stability analysis is presented. An indispensable illustrative example is bench tested to validate the effectiveness of the proposed approach. 相似文献
16.
Wen‐Jeng Liu 《Asian journal of control》2016,18(6):2037-2046
Many valuable properties of the state feedback method can not be applied to some class of control systems while some of the system states cannot be measured directly. An attractive alternative approach is to make good use of a state observer. In this paper, a new decentralized sliding mode observer (DSMO) is proposed for a class of nonlinear uncertain large‐scale systems (LSS) with lumped perturbations based on the sliding mode control (SMC) theory. Our main result presented here is that we introduce a new switching term to the traditional LSS observer design for a class of large‐scale system to generate a new decentralized sliding mode observer. The generalized matrix inverse concept is adopted to avoid using the un‐measurable state and the global reaching condition of the sliding mode for each error subsystem is guaranteed. The stability of each equivalent error subsystem is verified based on the strictly positive real concept. It also shows that the investigated uncertain large‐scale systems still possesses the property of insensitivity to the lumped perturbations as does the traditional linear system. Moreover, the state transformation approach is no longer needed as there is no longer concern about the problems of finding a suitable transformation or indirect estimated states, since the proposed DSMO is not based on the transformed system model. Finally, a numerical example with a series of computer simulations is given to demonstrate the validity of the proposed decentralized sliding mode observer. 相似文献
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In this paper, a generalized augmented transformation is considered for the quarter active suspension system with uncertainties. Specifically, the model uncertainties are converted to the augmented states and a new proportion differential sliding mode observer is used to estimate state variables and model uncertainties. A differential geometric method is applied to linearize the nonlinear suspension model. In order to weaken the vibration effect of sliding mode control force and reduce energy consumption, a fuzzy sliding mode controller is designed for the active suspension system and the fuzzy controller is applied to adjust switching control gain according to the reaching condition of sliding mode surface. The simulations are conducted to illustrate the effectiveness and advantages of this proposed observer and control strategy. 相似文献
19.
Ida Louise G. Borlaug Jan Tommy Gravdahl Jrgen Sverdrup‐Thygeson Kristin Y. Pettersen Antonio Loria 《Asian journal of control》2019,21(1):208-223
The underwater swimming manipulator (USM) is a snake‐like, multi‐articulated, underwater robot that is equipped with thrusters. One of the main purposes of the USM is to act like an underwater floating base manipulator. As such, it is essential to achieve good station‐keeping and trajectory tracking performance for the USM by using the thrusters and by using the joints to attain the desired position and orientation of the head and tail of the USM. In this ‘paper, we propose a sliding mode control (SMC) law, specifically the super‐twisting algorithm with adaptive gains, for the trajectory tracking of the USM's centre of mass. A higher‐order sliding mode observer is proposed for state estimation. Furthermore, we show the ultimate boundedness of the tracking errors. We demonstrate the applicability of the proposed control law and show that it leads to better performance than a linear PD‐controller. 相似文献
20.
In the present work, an active steering assistance system for heavy vehicles is developed to prevent lane departure and let the vehicle follow the road's centre line. The controller is based on the super‐twisting algorithm. An estimator based on the sliding mode observer is also developed to estimate the vehicle dynamics. The lateral positions and speeds are then controlled to keep the vehicle in the centre of the lane. The lateral offset and the relative yaw angle are supposed to be measured and the road curvature to be known. Some simulation results are given to show the quality of this steering assistance system. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献