Numerical algorithms for eigenvalue assignment by state feedback

Numerical algorithms are described for solving the eigenvalue assignment (EVA) problem for multi-input systems by means of state feedback. The multi-input EVA problem is first reduced to one or more single-input EVA problems where the single-input systems are in "upper Hessenberg form." An algorithm based on the well-known implicitly shifted QR algorithm is then described for solving the single-input EVA problem. Some variations on the use of these algorithms are also proposed to handle certain special cases. Numerical properties of the algorithms are discussed and examples are given to illustrate their numerical performance.     

Gain-scheduled H∞ controller with minimum Frobenius norm

For microcontroller implementations, H_∞ controllers with small numbers in their state-space realization are intended. Hence, minimum Frobenius norm is a design target. As an alternative, and useful for predetermining H_∞ gain schedules, the infinity norm is included with the help of ramifications points of the eigenvalue contour of the Hamiltonian matrix.     

High-speed and high-precision motion control with an optimal hybrid feedforward controller

An optimal feedforward controller which makes a hybrid usage of the shift (q) and delta (/spl delta/) operators is proposed for high-speed and high-precision digital motion control systems. Uncancellable discrete-time zeros arising from sampling the continuous-time plant at high rates, which make the mathematical inverse unstable, are handled in a natural way. The controller is optimized to have good performance in both low and high frequency ranges, and it is able to handle uncancellable discrete-time zeros in the right half plane. The optimization problem is generalized to an H/sup /spl infin// problem. Convex minimization is used to find the solution to the optimization problem. Simulation results and experiments carried out on an MC-510V Matsuura vertical machining center show superior performance of the proposed optimal hybrid feedforward controller.     

Matrix assignment with individual weights and selected controller restrictions

The design method of matrix assignment as a generalization of pole assignment is extended with some special features. Overstepping the optimal solution given by the Penrose point could be needed in the case of unstable plants. Individual weighting of the coefficient matrix differences is carried out and oriented on the numerical importance of the settings. Individual restrictions of the controller matrix are also included and are based on the given deterioration of state variables with noise. The paper also addresses minimum values of the controller norm which are located between singular values of the input matrix of the system.     

Sliding-mode motion controller with adaptive fuzzy disturbance estimation

This paper proposes a motion control scheme which belongs to the class of the control schemes known as sliding-mode control with disturbance estimation. A novel adaptive fuzzy disturbance estimator works as an estimator of a major part of robot dynamics. The adaptation algorithm is derived by using the Lyapunov stability theory and provides global asymptotic stability of the state errors, resulting in the sliding-mode regime. The structure of the disturbance estimator is optimized by the introduction of three fuzzy logic subsystems, based on the physical properties of the robot mechanism. This also significantly lowers the computational burden and enables real-time implementation. Performance of the proposed controller scheme, as well as some practical design aspects, are demonstrated by the control of a direct-drive robot.     

Robust controller with disturbance rejection for hydraulic servosystems

A controller is presented that improves the performance and reduces the sensitivity of hydraulic servo systems in the presence of parameter variations, nonlinear effects, and other disturbances. The control system has enhanced closed-loop stability and can recover from steady-state and transient error quickly and completely. It consists of a servo controller, an auxiliary controller, and a robust controller. Simulation and experimental results demonstrate the validity of the controller     

Channel assignment with limited channel-sharing in cellularnetworks-a homogeneous analysis

The granularity of frequency reuse of the conventional approach for channel assignment is a cluster (a partition of a coverage area). That means that the channels used in cells (partitions of a cluster) within the same cluster are distinctive. In this paper, we propose a different approach for channel assignment such that the channels are reused among cells in the same cluster. However, there are two constraints on the reuse of channels in a cluster to keep the cochannel interference in check. First, adjacent cells are not allowed to use the same channels. Second, the number of “one-hop-away” cells assigned the same channels is limited. The approach we take is based on the theory of finite projective planes. By mapping the sets of points of a finite projective plane to the channels assigned to a cell, channel reuse is achieved within a cluster. The performance evaluation is done in three parts. In the first part, we show that the channel reuse efficiency of the proposed approach is higher than that of the conventional approach with a tradeoff of a lower signal-to-interference (S/I) ratio. In the second part, the S/I is kept the same, and we demonstrate that the proposed approach has a higher channel reuse efficiency when the cluster size is reasonably small. In the third part, the worst case analysis for the situation that mobile users roam around the cell boundary is illustrated and a strategy of channel allocation is provided to avoid the worst case conditions     

An optimal and adaptive design of the feedforward motion controller

The zero phase error tracking controller (ZPETC) in motion control, as proposed by Tomizuka (1987) , renders the desirable zero phase error, but with a limited gain response. Moreover, a ZPETC, which is basically in a feedforward control structure, is very sensitive to modeling error. To improve the tracking accuracy of the ZPETC, this paper presents an optimal ZPETC design with a concise polynomial digital prefilter (DPF). The parameters of this well-designed DPF are obtained through the derived L₂-norm optimization. By cascading the developed DPF to the ZPETC, the resultant optimal ZPETC greatly improves the bandwidth of the tracking control systems while maintaining the zero phase error. Compared with other optimal approaches, the present design leads to much simpler procedures and fewer computations. Furthermore, the proposed optimal ZPETC can be adequately implemented as an adaptive ZPETC by including real-time estimation technique to cope with the external load perturbation and parameter variation. Compared with the other adaptive approaches, the optimal concept is used in the present adaptive ZPETC, and it also renders more accurate results because of its improved magnitude response. Experimental results on a DC servo table with different controllers indicate that when there is no loading, the present optimal ZPETC achieves the best tracking performance. Moreover, the adaptive ZPETC achieves the most satisfactory results when an external load is applied     

MIMO multirate feedforward controller design with selection of input multiplicities and intersample behavior analysis

Inversion-based feedforward control is a basic method of tracking controls. The aim of this paper is to design MIMO multirate feedforward controller that improves continuous-time tracking performance in MIMO LTI systems considering not only on-sample but also intersample behavior. Several types of MIMO multirate feedforward controllers are designed and evaluated in terms of the 2-norm of the control inputs. The approach is compared with a conventional MIMO single-rate feedforward controller in simulations. The approach improves the intersample behavior through the optimal selection of input multiplicities with MIMO multirate system inversion.     

Decentralized control via disturbance attenuation and eigenstructure assignment

In this brief, a simple approach is proposed for decentralized control of linear large-scale systems. Sufficient conditions for diagonal dominance of closed-loop large-scale systems are derived. Based on these conditions, the interactions between the subsystems can be considered as external disturbances for each isolated subsystem. Then, a previously proposed approach is used to attenuate disturbances via dynamic output compensators based on complete parametric eigenstructure assignment. Through attenuation of the disturbances, the closed-loop poles of the overall system are assigned in the desirable region, by assigning the eigenstructure of each isolated subsystem appropriately. An example is given to show the effectiveness of the proposed method.     

Multidimensional feedforward compensator for industrial systems through pole assignment regulator and observer

A feedforward-compensator-design technique is presented for industrial control systems. The proposed feedforward compensator can improve dynamic characteristics of multidimensional systems by modifying the input signals. The multidimensional feedforward-compensator design is based on the pole assignment regulator, the minimal-order observer, and the conversion from a closed-loop system to an open-loop system. The effectiveness of the proposed feedforward compensator is demonstrated by a simulation study of temperature control of a thermal power plant and by experiments of the contour control of an articulated robot arm.     

Extension to the method of Anderson and Luenberger for eigenvalue assignment

A method is described which allows the canonical decomposition of Anderson and Luenberger to be employed systematically for eigenvalue assignment in linear multivariable systems in cases where their method cannot be applied directly, or where one wishes to exploit extra design freedom.     

Filtered-error RLS for self-tuning disturbance feedforward control with application to a multi-axis vibration isolator

High performance vibration isolation can be realized by disturbance feedforward control with a self-tuning generalized FIR filter and residual noise shaping. For this application, filtered-error recursive least squares (FeRLS) self-tuning is proposed in a multi-input multi-output context. In comparison to filtered-error least mean squares (FeLMS), FeRLS achieves faster and more uniform parameter convergence without the need of pre-whitening. Efficient implementation is realized by exploiting sparsity in the involved matrices. Feasibility of implementation is demonstrated on a multi-axis hard-mount vibration isolation setup. Experimental results show the better parameter convergence and the ability to track changes in the floor vibration spectrum. A reduction of the transmissibility of floor vibrations up to 40 dB in the frequency range of interest is obtained, reducing vibration power by 90–94% in the 1–300 Hz frequency band in multiple directions.     

Design freedom in the method of Anderson and Luenberger for eigenvalue assignment

It is shown that certain zeros in row vectors involved in the calculation of state-variable feedback laws by the method of Anderson and Luenberger may be replaced by elements of arbitrary value, without affecting system eigenvalues. Minimisation of the norm of a row of the feedback matrix is suggested as one possible way to exploit this freedom.     

Decoupling and pole-zero assignment of singular systems with dynamic state feedback

This paper refers to the problem of designing a linear state feedback dynamic controller for single-input, single-output decoupling of linear, time-invariant, singular systems. Sufficient conditions are established for the state-feedback decoupling problem to have a solution. In the case where the system satisfies these conditions, the class of controller matrices which decouple the system is given. Finally a method is presented for pole-zero placement in the decoupled singular system and a structure is described for the realization of the generalized transfer function matrices.     

有限波长转换能力的OBS网波长分配算法研究

结合国内外最新的研究动态,针对有限波长转换能力的光突发交换网中亟待解决的突发包资源竞争问题,探讨了各种传统的波长分配算法,并通过对其特点的分析和综合比较,提出了一种新的适合有限波长转换能力光突发交换网特点的动态波长分配算法,此算法可以实现更低的全网突发包阻塞率.     

Surface sliding mode controller for chaotic oscillation in power system with power disturbance

With the rapid development of the power industry,the possibility of chaotic oscillation increases in the power system,and the importance of maintaining the stability of the power system is prominent.Through a fourth-order power system model with power perturbation term built,the Lyapunov exponent spectrum,bifurcation diagram and spectral entropy were analyzed,respectively.The influence of power disturbance terms on power system motion was discussed in detail.Moreover,a dynamic surface sliding mode controller was designed based on the switching function with relay characteristics.Simulation results show that the controller can suppress the chaotic oscillation quickly and smoothly,and effectively avoid chattering and own strong robustness.     

数字PID温控器7参数辨识和扰动抑制

扩展阿斯特罗姆(Astrom,Karl Johan)的继电反馈法在温控器中的应用,把最初仅辨识PID控制3参数(比例系数、积分和微分时间常数)增加到包括温控系统中最大升温与降温率、平均维持功率和控制周期在内的7参数(依次表示为KP,、Ti、Td、TR_RM、TD_RM、AMPow和Tp);用"温变速率法"快速辨识热负载...