共查询到20条相似文献，搜索用时 109 毫秒
1.
When designing lossless networks, one is faced with the problem of choosing a zero configuration for the reflection coefficient ?(s). Bode showed that if parasitic capacitances are present as well as for power transfer optimization, the best zero configuration is to locate all of them in the left half-plane. Recently, Bode's result was generalized to include parasitic immitances at both ends (source and load) of the quadripole.This work adds a new result to the theory by looking at the overall transfer function poles. It is shown that (a) if the source resistance varies, one should select left half-plane zeros for ?(s); and (b) if the load impedance varies, one should select right half-plane zeros.The pole sensitivity criterion used is the distance between the actual transfer function poles and the poles of the ideal transfer function. 相似文献
2.
《Journal of The Franklin Institute》2022,359(8):3831-3856
Aiming at early detection of faults in dynamic systems subject to external periodic disturbances, this paper proposes a new generalized proportional-integral observer (GPIO) fault detection scheme with zero-pole joint optimization and novel complex coefficient gain (CCG) of residual evaluation. The focus of the proposed scheme is to reduce the adverse impacts caused by the semi-stationary periodic disturbance whose spectrum is uneven, with most energy being at some dominant frequencies. The proposed GPIO with a complex coefficient gain is designed in a two-stage procedure. In the first stage of zero assignment and pole optimization, the additional zeros introduced by the GPIO’s integration action are allocated to near the disturbance frequency. The gain of the transfer function matrix relating from the disturbances to the fault indicator signals is minimized by pole optimization. In the second stage of designing complex coefficient gain in residual evaluation, the unique feature of rank-deficient caused by the additional zeros assigned in stage one is further exploited to cancel the disturbances in the fault indicator signals (which is also referred to as the fault detection residual in this article). It is proved that, for an arbitrary periodic disturbance with a specific spectrum, the remnant components of the disturbance in the indicator signals generated by the GPIO can cancel each other by a complex gain vector, which can be determined by the zero eigenvalue’s left eigenvector of the rank-deficient of the disturbance transfer function matrix. The sufficient conditions for the convergence of the proposed fault detection filter are also given. Numerical examples illustrate the proposed method’s better performance in detecting minor faults. 相似文献
3.
Synthesis techniques are given for any one element kind driving point function in two variables, s and x. Conditions for the realization of some two element kind driving point functions in s and x are also developed. Using active elements, any such function is shown to be realizable. Driving point functions in s and x with certain types of fixed (independent of x) and varying (dependent on x) real zeros and poles are shown to be realizable using only F-elements. Applications are presented. 相似文献
4.
In this paper, the stability equation method is applied to the analysis of nonlinear systems with characteristics equations having complex coefficients. Three types of systems are studied: those with unstable open-loop poles, unstable characteristics roots or an equal number of open-loop poles and zeros. 相似文献
5.
F.L. N-Nagy 《Journal of The Franklin Institute》1983,315(1):49-60
This paper describes the derivation of Heaviside's decomposition in matrix frame presentation. For simplicity, the response transform having one multiple pole and any number of distinct poles is considered. There is no restriction on the number and the order of zeros. The aim is to avoid the repeated differentiations in the algorithm for the computation of both residue and constituent coefficients about the multiple pole. This will be referred to as the RRM (Residue and Resolvent Matrices) method and adopted to time response derivation of dynamic systems. The RRM method is also applicable as a mathematical catalyst to the algebraic solution of differentiation and integration of complex functions in the s domain used for system optimisation. 相似文献
6.
This paper deals with asymptotic rejection of a multi-sinusoidal signal for linear single-input single-output stable systems with unknown structure. An adaptive orthogonal signals generator is used to both reconstruct the disturbance and cancel its effect on the system output. An interesting feature is that the disturbance is removed by the generated internal signals with no additional dynamics in the cancellation algorithm. A fractional-order controller is designed which guarantees the closed-loop stability of the system if the location of the plant frequency response at the estimated frequencies lies in a half-plane passing through the origin of the complex plane, i.e. no information about the order of the system to be controlled, the relative degree, the nature of its poles and zeros, is required. The case of multi-sinusoidal disturbance is also analyzed. Simulations and comparisons with existing approaches are presented that highlight the performances of the proposed method. 相似文献
7.
A linearly variable element is any passive two-terminal network element in which the immittance varies linearly with respect to an independent (of frequency) real variable, x. A definite set of fundamental passive two terminal network elements (F- elements) consisting of fixed passive elements and linearly variable elements is presented. It is shown that any network consisting of only F-elements has a driving point immittance, D(s,x), that is positive real for s complex, x real and positive real for x complex, s real. Conditions on the variable coefficients, degree and location of zeros and poles of D(s,x) are established. A method of testing whether D(s,x) is positive real for one complex and one real variable is developed. This testing is accomplished by extending the Hurwitz and Sturm test to one complex and one real variable. 相似文献
8.
The construction of nomographs for transitional classical filters is described. Gain functions of classical filters are related to filter requirements resulting in a formulation for the general gain nomograph. The transitional filters that are products of approximating polynomials are incorporated into the general gain nomograph resulting in transitional filter nomographs that are sums of the individual nomographs. Nomographs for transitional filters using alternative forms where poles are interpolated are also considered. The resulting nomographs allow for quick optimization of transitional filter frequency response in many cases. Design examples are submitted and discussed. The proposed transitional filter nomographs provide the engineer with increased insight into the selection of classical transitional filters with optimum frequency response. 相似文献
9.
Even when based on simple models, a fed-batch fermentation process can demonstrate several different forms of complex dynamic behaviours throughout the course of its operation. One of the most intriguing forms of dynamic behaviours that can occur at some points during the fed-batch operation is represented by a fourth-order integrating-unstable system with multiple RHP zeros. To deal with the stabilization of this complex dynamics, a new triple-loop multi-scale control (TL-MSC) scheme is proposed. This scheme aims to first decompose the complex dynamics into three simpler sub-systems which are then separately addressed in a multi-scale structure. This paper presents both the fundamental of TL-MSC scheme and the details of its design. A typical fed-batch alcoholic fermentation is shown as an example to demonstrate the applicability of the new scheme. 相似文献
10.
A simple numerical method for computing the time domain response of linear time invariant systems described by their transfer functions is presented. The method does not require computation of transfer function poles or residues; it is not influenced by the multiplicity of poles or zeroes, nor does it require computation of the matrix exponential. Rather, it is based on a numerical method for inverting Laplace transforms. It is equivalent to very high order, absolutely stable numerical integration. Stiff systems present no problems. 相似文献
11.
Xi-Sheng Zhan Zhi-Hong Guan Xian-He Zhang Fu-Shun Yuan 《Journal of The Franklin Institute》2013,350(10):3205-3216
The optimal tracking problem for single-input–single-output (SISO) networked control system over a communication channel with packet dropouts is studied in this paper. The tracking performance is measured by the energy of the error signal between the output of the plant and the reference signal. It is shown that the optimal tracking performance is constrained by nonminimum phase zeros, unstable poles, the characteristics of the reference signal and packet dropout probability, and the optimal controller is obtained. It is also shown that when the communication constraint does not exist, the optimal tracking performance reduces to the existing normal tracking performance of the control system without a communication channel. The result shows how the packet dropouts probability of a communication channel may fundamentally constrain a control system's tracking ability. Some typical examples and simulations are given to illustrate the theoretical results. 相似文献
12.
M. Malek-Zavarei 《Journal of The Franklin Institute》1980,309(3):125-134
A class of unstable relay-controlled plants possessing one pole at the origin and two non-zero distinct real poles is studied. Cases corresponding to one or both non-zero poles in the right half-plane are considered. In each case a controller which simultaneously reduces the error and its first and second derivatives to zero in minimum time is designed. Also the class of admissible inputs is found which, after a minimum transient time, can be followed without any error. Through some linear transformations, it is shown that the equations of the switch curve and the switch surface can be made independent of the plant's constant gain and dependent only on the ratio of the non-zero pole values. It is established that in both regulating and tracking modes the error and its first and second derivatives can be reduced to zero with at most two switching reversals of the control provided that the initial values of error and/or its derivatives fall in a “controllable region”. 相似文献
13.
泊松回归模型常常用于计数数据的研究中,然而在实际数据中零值的比例可能远远大于泊松分布中取零值的概率,而且这些零值通常都有其特殊含义.此外计数数据可能是分组数据,即观测到的数据不是确切值而只是已知其落在某一个区间范围之内;或者某些特定的数据,例如工资,要先对它进行人为的分组然后再进行分析.考虑一种零膨胀泊松半参数回归模型来处理上述分组计数数据.该模型中泊松分布的期望与协变量之间采用部分线性连接函数,而零值的概率与协变量之间采用线性连接函数.利用Sieve极大似然估计方法来估计该回归模型中参数和非参数函数,并提出了一种得分检验方法来检验是否存在零膨胀.在一定正则条件下,获得了Sieve极大似然估计的渐近性质,证明了参数部分的估计是强相合,渐近正态及渐近有效的;同时非参数函数的估计达到了最优收敛速度.模拟研究表明,估计和检验方法效果都比较好,最后将此模型和推断方法应用于一组公共卫生领域实际数据研究. 相似文献
14.
《Journal of The Franklin Institute》2022,359(5):1795-1820
For a class of large-scale nonlinear time-delay systems with uncertain output equations, the problem of global state asymptotic regulation is addressed by output feedback. The class of systems under consideration are subject to feedforward growth conditions with unknown growth rate and time delays in inputs and outputs. To deal with the system uncertainties and the unknown delays, a novel low-gain observer with adaptive gain is firstly proposed; next, an adaptive output feedback delay-free controller is constructed by combining Lyapunov-Krasovskii functional with backstepping algorithm. Compared with the existing results, the controllers proposed are capable of handling both the uncertain output functions and the unknown time delays in inputs and outputs. With the help of dynamic scaling technique, it is shown that the closed-loop states converge asymptotically to zero, while the adaptive gain is bounded globally. Finally, the effectiveness of our control schemes are illustrated by three examples. 相似文献
15.
Sigmund K. Waldorf 《Journal of The Franklin Institute》1932,213(6):605-622
If the amplifier-oscillograph is to attain the fidelity of frequency reproduction of the unaided oscillograph, the amplifier circuit must be designed, constructed, and used with discretion. In no portion of the circuits, in neither the amplifier itself nor the connected measuring circuits, is it permissible for the associated resistances, capacitances, and inductances to produce time constants so large as to suppress any of the frequencies which the oscillograph vibrator would reproduce normally. Steadiness of the amplifier is a prime consideration, usually attainable with moderately high gain units by having sure electrical contacts and the component parts operated conservatively within their respective ratings. Interference is frequently a source of considerable difficulty and great care must be exercised not to permit it to cause erroneous measurements.A method of compensating for the steady component of the amplifier output current has been investigated and when properly used, has been found neither to impair the sensitivity of the instrument appreciably nor to require critical adjustment.Consideration also has been given to the photographic technique involved in oscillography in order that its full possibilities might be realized.An instrument has been described and discussed which had a sensitivity of about 1.7 millivolts per mm. deflection. When the maximum permissible input resistance of 0.1 megohm was used, a current sensitivity of about 1.7 × 10?8 amperes per mm. deflection was attained. A greater value of input resistance could not be used without the possibility of introducing serious distortion. 相似文献
16.
Baoxian Wang Yanli Lv Jigui Jian Xiaowei Jiang 《Journal of The Franklin Institute》2019,356(16):8971-8995
This paper studies the trade-off performance between tracking performance and control input energy of the multi-input multi-output(MIMO), linear and time-invariant(LTI) system over an additive coloured Gaussian noise(ACGN) channel and the encoder-decoder strategies. The restriction that filter in the encoder-decoder strategy must be diagonal matrix is not necessary. And some new results are derived according to the inner-outer factorization. The results show that the trade-off performance is correlated to the unstable pole, non-minimum phase zero of the system. Also new poles and zeros generated by the non-diagonal encoder-decoder strategies may affect the trade-off performance. At last, two examples with different filters and different encoder-decoder strategies are discussed to validate the conclusions. The various encoder-decoder strategies revealed by the simulations may enhance or deteriorate the trade-off performance proposed in this paper. 相似文献
17.
18.
Through the coupling of commutator machines, self-excited alternating power can be spontaneously generated with no external electrical excitations. Standard frequency- domain analysis is applied to the various equivalent circuits for each configuration. Conventional series and shunt self-excited generators are shown to have a single pole in the right-half s plane, indicating growing exponential solutions, whereas coupled generators are shown to have a pair of complex conjugate poles in the right-half s plane, indicating overstable modes, which oscillate as they grow, resulting in self-excited two-phase alternating power generation. Because of this interesting result, the analysis is extended to consider N-coupled generators which shows the existence of many overstable modes, resulting in multi-frequency, multi-phase power generation. The existence of electromechanical alternating self-excitation is demonstrated with the periodic speed reversals of a separately exited d.c. motor, which has its armature in series with the field and armature windings of a generator. Experimental results are presented which indicate that the linear circuit representation is appropriate for the onset and early time interval of these self-excited machines. The magnetic saturation characteristic limits the exponential growth so that a steady state results. These devices are of use in low-frequency, high-power applications, as well as serving as a model for other spontaneous mechanisms in nature. 相似文献
19.
Myron Pawley 《Journal of The Franklin Institute》1933,215(2):133-147
A selective amplifier is developed which is simple, and more flexible than other types. It utilizes an audio transformer with a variable series resistance in the primary circuit, and a variable secondary load capacitance both of which may be adjusted to give broad or narrow peaked amplification at any frequency within a wide range, or flat amplification throughout this range. Theoretical and experimental amplification curves are shown, and a transient solution gives the primary and secondary currents resulting when a voltage is suddenly applied to the amplifier. This analysis shows that the time constants for the circuit are comparable with those for other peaked amplifiers. Oscillograms are shown illustrating the transient behavior of the amplifier. 相似文献
20.
A two-step iterative method (1,2) for a reduction in the order of linear continuous-time systems, given in the state equation or the transfer function, is extended to reduce discrete-time systems. The method requires the optimization of the residues and eigenvalues (or poles) belonging to an objective function. The objective function to be minimized is chosen as the finite sum of the squares of the error between the step responses of the reduced model and the original system. This scheme is continued cyclically until the objective function is satisfactorily minimized. By investigating the initial selection of the eigenvalues in the reduced-order model, it is found that the dominant eigenvalues of the original system give a good approximation. Further, the resulting model is always stable, assuming the original system is stable. As shown in a numerical example, the proposed method is superior to the other methods of model reduction in both steady-state and transient responses, and in the value of the sum of the squares of the error. 相似文献