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1.
A robust neuro-adaptive controller for uncertain flexible joint robots is presented. This control scheme integrates H-infinity disturbance attenuation design and recurrent neural network adaptive control technique into the dynamic surface control framework. Two recurrent neural networks are used to adaptively learn the uncertain functions in a flexible joint robot. Then, the effects of approximation error and filter error on the tracking performance are attenuated to a prescribed level by the embedded H-infinity controller, so that the desired H-infinity tracking performance can be achieved. Finally, simulation results verify the effectiveness of the proposed control scheme. 相似文献
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A new method of robust controller synthesis is introduced which is an extension of robust stabilization to robust stability-degree assignment. This method guarantees a lower bound of stability degree for all uncertainties within a prescribed magnitude band. The method is applied to the control of four types of flexible structures, namely, colocated beam, non-colocated beam, beam with moving base and large scale satellite model. Excellent performances have been obtained experimentally with respect to the response speed and the robustness. 相似文献
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A self-organizing fuzzy logic controller for the active control of flexible structures using piezoelectric actuators 总被引:1,自引:0,他引:1
This paper proposes an on-line self-organizing fuzzy logic controller (FLC) design applied to the control of vibrations in flexible structures containing distributed piezoelectric actuator patches. In this methodology, the fuzzy rules are generated using the history of input/output (I/O) pairs without using any plant model. The generated rules are stored in the fuzzy rule space and updated on-line by a self-organizing procedure. The validity of the proposed fuzzy logic control has been demonstrated experimentally in a steel cantilever test beam and a set of experimental tests are made in the system to verify the efficiency of the on-line self-organizing fuzzy controller. 相似文献
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针对带有大型挠性网状天线航天器存在的挠性结构不确定性问题,提出了基于比例微分(PD)结构滤波器的鲁棒H∞双层反馈控制方法,第1层采用经典的PD+结构滤波器,确保刚体部分双积分环节稳定,第2层在提取第1层标称模型后,给出通用加权函数,通过构造增广模型得到鲁棒H∞控制器.该控制器结构简单,适合工程应用.通过仿真表明,本方法相对于传统PID+结构滤波器方法能够快速稳定三轴姿态;当结构参数变化较大且三轴姿态偏置为动态时变时,有可能导致传统方法失稳,而本方法具有较强的鲁棒适应性,仍能完成航天器天线的指向任务. 相似文献
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Appasaheb N. Madiwale
Wassim M. Haddad
Dennis S. Bernstein
《Systems & Control Letters》1989,12(5):393-407In a recent paper a unification of the H2 (LQG) and H∞ control-design problems was obtained in terms of modified algebraic Riccati equations. In the present paper these results are extended to guarantee robust H2 and H∞ performance in the presence of structured real-valued parameter variiations (ΔA, ΔB, ΔC) in the state space model. For design flexibility the paper considers two distinct types of uncertainty bounds for both full- and reduced-order dynamic compensation. An important special case of these results generates H2/H∞ controller designs with guaranteed gain margins. 相似文献
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Kuang-Chiung Chang Hung-Ching Lu 《Mathematics of Control, Signals, and Systems (MCSS)》1990,3(1):81-96
In this paper, robust stabilization conditions based on theH
∞-norm are derived for multivariable feedback systems under perturbations and constrained control. The parametrized controller
of Youlaet al. is employed to treat this problem. In addition, a necessary and sufficient condition is derived for the solvability of the
synthesis problem for a controller which achieves robust stability. Finally, a design procedure is proposed for selecting
the parameters of the robust controller, and an illustrative example is given. 相似文献
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Matthew O.T. Cole Author Vitae Theeraphong Wongratanaphisan Author Vitae 《Automatica》2008,44(11):2876-2883
Model-based feedback control of vibration in flexible structures can be complicated by the possibility that interaction with an external body occurs. If not accounted for, instability or poor performance may result. In this paper, a method is proposed for achieving robust vibration control of flexible structures under contact. The method uses robust linear state feedback, coupled with a state estimation scheme utilizing contact force measurement. Uncertain contact characteristics are modelled by a sector-bounded non-linear function, such that state feedback gains can be synthesized using a matrix inequality formulation of the Popov stability criterion. A separation theorem is used to establish a robust H2 cost bound for the closed loop system. Experimental results from a multi-mode flexible structure testbed confirm that vibration attenuation and stability can be maintained over a broad range of contact characteristics, in terms of compliance and clearance. 相似文献
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A new robust controller is proposed to regulate both flexural vibrations and rigid body motion of a hydraulically driven flexible ann. The controller combines backsteppmg control and sliding mode to arrive at a controller capable of dealing with a nonlinear system with uncertainties. The sliding mode technique is used to achieve an asymptotic joint angle and vibration regulation in the presence of payload uncertainty by providing a virtual torque input at the joint while the backstepping technique is used to regtthte the spool position of a hydraulic valve to provide the required torque. It is shown that there is no chatter in the hydraulic valve, which results in smoother operation of the system. 相似文献
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The problem of robustly stabilizing an infinite dimensional system with transfer function G, subject to an additive perturbation Δ is considered. It is assumed that: G ε
0(σ) of systems introduced by Callier and Desoer [3]; the perturbation satisfies |W1ΔW2| < ε, where W1 and W2 are stable and minimum phase; and G and G + Δ have the same number of poles in
+. Now write W1GW2=G1 + G1, where G1 is rational and totally unstable and G2 is stable. Generalizing the finite dimensional results of Glover [12] this family of perturbed systems is shown to be stabilizable if and only if ε σmin (G*1)( = the smallest Hankel singular value of G*1). A finite dimensional stabilizing controller is then given by
where
2 is a rational approximation of G2 such that
) and K1 robustly stabilizes G1 to margin ε. The feedback system (G, K) will then be stable if |W1ΔW2| ∞< ε − Δ. 相似文献
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12.
带刚性基柔性附件振动鲁棒控制 总被引:2,自引:0,他引:2
研究了刚体基上柔性附件的振动鲁棒控制问题.介绍了结构奇异值μ理论,基于此理论设计鲁棒控制器,用压电材料作传感器和作动器(μ),用输出乘性不确定性结构来描述低阶标称模型与实际系统的误差,给出了系统μ控制器综合框架.以柔性梁附件为对象示例了分析过程.数值仿真结果表明μ控制器具有良好的鲁棒性能,用于振动控制是必要且可行的. 相似文献
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This paper proposes a fractional-order integral controller, FI, which is a simple, robust and well-performing technique for vibration control in smart structures with collocated sensors and actuators. This new methodology is compared with the most relevant controllers for smart structures. It is demonstrated that the proposed controller improves the robustness of the closed-loop system to changes in the mass of the payload at the tip. The previous controllers are robust in the sense of being insensitive to spillover and maintaining the closed-loop stability when changes occur in the plant parameters. However, the phase margin of such closed-loop systems (and, therefore, their damping) may change significantly as a result of these parameter variations. In this paper the possibility of increasing the phase margin robustness by using a fractional-order controller with a very simple structure is explored. This controller has been applied to an experimental smart structure, and simulations and experiments have shown the improvement attained with this new technique in the removal of the vibration in the structure when the mass of the payload at the tip changes. 相似文献
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Y. Arfiadi 《Computers & Structures》2006,84(12):798-807
This paper considers nonlinear controller under bounded capacity of the actuators. The controller is first derived based on bang-bang type controllers. In order to avoid high-speed switching effect, a continuous function is used to replace signum function in bang-bang controller. Although a variety of continuous and bounded functions are available, a hyperbolic tangent is chosen as the candidate of the controller. The proposed control law is then applied to three- and six-storey buildings utilising active bracing systems. Different earthquake excitations with various intensities are used in the simulation to show the potential benefit of the proposed control law. Numerical results show that in contrast to bang-bang type controllers that utilise maximum capacity of the actuator, the proposed controller is adaptive in the sense that the maximum capacity of the actuator is utilised when only needed. In addition, the proposed controller can avoid the high-speed switching effects presence in the bang-bang controllers if the weighting variables are chosen appropriately. 相似文献
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The robust stability and stabilization, and H-infinity control problems for discrete-time Markovian jump singular systems with parameter uncertainties are discussed. Based on the restricted system equivalent (r.s.e.) transformation and by introducing new state vectors, the singular system is transformed into a discrete-time Markovian jump standard linear system, and the linear matrix inequality (LMI) conditions for the discrete-time Markovian jump singular systems to be regular, causal, stochastically stable, and stochastically stable with °- disturbance attenuation are obtained, respectively. With these conditions, the robust state feedback stochastic stabilization problem and H-infinity control problem are solved, and the LMI conditions are obtained. A numerical example illustrates the effectiveness of the method given in the paper. 相似文献
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Said Oucheriah Author Vitae 《Automatica》2006,42(11):1863-1867
This brief paper deals with the problem of robust exponential stabilization of a class of dynamic systems subject to time-varying delays, external disturbances and control saturation. A linear memoryless state feedback controller is synthesized to guarantee that there is a domain of admissible initial conditions from which all solutions of the class of systems considered converge exponentially to a ball with a prespecified convergence rate. The problem is formulated as a two-step optimization problem with matrix inequality constraints to enlarge the size of the ball of admissible initial conditions. 相似文献
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The robust stability and stabilization, and H-infinity control problems for discrete-time Markovian jump singular systems with parameter uncertainties are discussed. Based on the restricted system equivalent (r.s.e.) transformation and by introducing new state vectors, the singular system is transformed into a discrete-time Markovian jump standard linear system, and the linear matrix inequality (LMI) conditions for the discrete-time Markovian jump singular systems to be regular, causal, stochastically stable, and stochastically stable with 7- disturbance attenuation are obtained, respectively. With these conditions, the robust state feedback stochastic stabilization problem and H-infinity control problem are solved, and the LMI conditions are obtained. A numerical example illustrates the effectiveness of the method given in the oaoer. 相似文献
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The paper discusses the use of a simple position control system approach to improve the performance of lightly damped dynamic systems. This approach uses a delayed position feedback signal to actively control the vibrations of flexible structures. A complete analysis of the stability of a single-link flexible manipulator under time delay control is presented and critical values of time delay for a given controller gain have been determined. The paper also presents a short comparison between the delayed feedback signal control and the linear quadratic regulator. 相似文献
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In some applications, vibration control objectives may require reduction of levels at locations where control system components cannot be sited due to space or environmental considerations. Control actuators and error sensors for such a scenario will need to be placed at appropriate locations which are potentially remote from the points where ultimate attenuation is desired. The performance of the closed loop system, therefore, cannot be assessed simply by the measurement obtained at this local error sensor. The control design objective has to take into account the vibration levels at the remote locations as well. A design methodology was recently proposed that tackles such problems using a single-loop feedback control architecture. The work in this paper describes an extension of this control design procedure to enable the systematic design of multiple decentralised control loops. The approach is based upon sequential loop closing and conditions are provided that ensure that closed loop stability is maintained even in the event of failure in some control loops. The design procedure is illustrated through its application to a laboratory scale slab floor that replicates the problems associated with human induced vibration in large open-plan office buildings. The experimental results demonstrate the efficacy of the approach and significant suppression of the dominant low frequency modes in the floor is achieved using two independent acceleration feedback control loops. 相似文献