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A recursive Switched-Capacitor DC-DC Converter Achieving 2^N-1 Ratios With High Efficiency Over a Wide Output Voltage Range

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IEEE JOURNAL OF SOLID-STATE CIRCUITS 2014年第12期49卷 2773-2787页

作者： Salem, Loai G. Mercier, Patrick P. Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

A recursive Switched-Capacitor (RSC) topology is introduced that enables reconfiguration among 2(N)-1 conversion ratios while achieving minimal capacitive charge-sharing loss for a given silicon area. All 2(N)-1 ratios are realized by strategically interconnecting N 2:1 SC cells either in series, in parallel, or in a stacked configuration such that the number of input and ground connections are maximized in order to minimize cascaded losses. Importantly, all ratios are dynamically reconfigurable without disconnecting a single capacitor, all while ensuring optimal capacitance/ conductance relative-sizing. The RSC topology is inherently regular, enabling recursive inter-cell connection and recursive binary-slicing that implement ratio-reconfiguration with minimum complexity and losses. A scalable all-digital binary search controller is employed to perform ratio-reconfiguration among the available 2(N)-1 ratios without using any ratio-threshold generation circuitry. To validate the topology, a 4 bit RSC is fully integrated in 0.25 mu m bulk CMOS using MIM capacitors, achieving greater than 70% efficiency over a 0.8-2.2 V output voltage range with 85.8% peak-efficiency from a 2.5V input supply. Compared to a co-fabricated three-ratio (1/3, 1/2, 2/3) Series-Parallel SC converter, the RSC achieves a 40.4% larger output operating range (from 0.04 to 2.2 V), and fills the efficiency-drops in-between the three-ratios by 8% with a 940 Omega load.

关键词： Binary search DC-DC converter dynamic voltage scaling (DVS) portable electronics power electronics power management pulse frequency modulation (PFM) recursive algorithm switched-capacitor voltage regulator wide voltage range

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Minimum-Variance recursive Filtering Over Sensor Networks With Stochastic Sensor Gain Degradation: algorithms and Performance Analysis

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IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS 2016年第3期3卷 265-274页

作者： Liu, Yang Wang, Zidong He, Xiao Zhou, D. H. Shandong Univ Sci & Technol Coll Elect Engn & Automat Qingdao 266590 Peoples R China Brunel Univ London Dept Comp Sci Uxbridge UB8 3PH Middx England Tsinghua Univ Dept Automat TNList Beijing 100084 Peoples R China

This paper is concerned with the minimum variance filtering problem for a class of time-varying systems with both additive and multiplicative stochastic noises through a sensor network with a given topology. The measurements collected via the sensor network are subject to stochastic sensor gain degradation, and the gain degradation phenomenon for each individual sensor occurs in a random way governed by a random variable distributed over the interval [0, 1]. The purpose of the addressed problem is to design a distributed filter for each sensor such that the overall estimation error variance is minimized at each time step via a novel recursive algorithm. By solving a set of Riccati-like matrix equations, the parameters of the desired filters are calculated recursively. The performance of the designed filters is analyzed in terms of the boundedness and monotonicity. Specifically, sufficient conditions are obtained under which the estimation error is exponentially bounded in mean square. Moreover, the monotonicity property for the error variance with respect to the sensor gain degradation is thoroughly discussed. Numerical simulations are exploited to illustrate the effectiveness of the proposed filtering algorithm and the performance of the developed filter.

关键词： Error boundedness minimum variance filtering monotonicity recursive algorithm sensor gain sensor network

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Pseudo-fractional ARMA modelling using a double Levinson recursion

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IET CONTROL THEORY AND APPLICATIONS 2007年第1期1卷 173-178页

作者： Ortigueira, M. D. Serralheiro, A. J. Univ Nova Lisboa Fac Ciencias & Tecnol P-2829516 Caparica Portugal INESC ID L2F P-1000029 Lisbon Portugal Acad Mil P-1150175 Lisbon Portugal

The modelling of fractional linear systems through ARMA models is addressed. To perform this study, a new recursive algorithm for impulse response ARMA modelling is presented. This is a general algorithm that allows the recursive construction of ARMA models from the impulse response sequence. This algorithm does not need an exact order specification, as it gives some insights into the correct orders. It is applied to modelling fractional linear systems described by fractional powers of the backward difference and the bilinear transformations. The analysis of the results leads to propose suitable models for those systems.

关键词： autoregressive moving average processes poles and zeros bilinear transformations recursive algorithm impulse response ARMA modelling backward difference double Levinson recursion pseudo-fractional ARMA modelling transient response fractional linear systems

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A novel suboptimal method for solving polynomial filtering problems

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AUTOMATICA 2015年 62卷 26-31页

作者： Luo, Xue Jiao, Yang Chiou, Wen-Lin Yau, Stephen S. -T. Beihang Univ Sch Math & Syst Sci Beijing 100191 Peoples R China Univ Illinois Dept Math Stat & Comp Sci Chicago IL 60607 USA Fu Jen Catholic Univ Dept Math New Taipei Taiwan Tsinghua Univ Dept Math Sci Beijing 100084 Peoples R China

In this paper we derive the stochastic differentials of the conditional central moments of the nonlinear filtering problems, especially those of the polynomial filtering problem, and develop a novel suboptimal method by solving this evolution equation. The basic idea is to augment the state of the original nonlinear system by including the original states' conditional central moments such that the augmented states form a so-called bilinear system after truncating. During our derivation, it is clear to see that the stochastic differentials of the conditional central moments of the linear filtering problem (i.e., f, g and h are all at most degree one polynomials) form a closed system automatically without truncation. This gives one reason for the existence of optimal filtering for linear problems. On the contrary, the conditional central moments form an infinite dimensional system, in general. To reduce it to a closed-form, we let all the high enough central moments to be zero, as one did in the Carleman approach (Germani et al., 2007). Consequently, a novel suboptimal method is developed by dealing with the bilinear system. Numerical simulation is performed for the cubic sensor problem to illustrate the accuracy and numerical stability. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Polynomial filtering problems Suboptimal filter recursive algorithm Estimation theory

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Command limiting in reconfigurable flight control

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1998年第4期21卷 639-646页

作者： Bodson, M Pohlchuck, WA Univ Utah Dept Elect Engn Salt Lake City UT 84112 USA

Limits on the motion and on the rate of motion of the actuators driving the control surfaces of aircraft significantly affect the performance of flight control systems. After a failure or damage to the aircraft, the constraints become even more restrictive because of the loss of control power. There is also often an increase in cross couplings between the axes and, for a period of time, a significant uncertainty about the moments generated by the individual control surfaces. A model reference adaptive control algorithm is considered for flight control reconfiguration. The tracking performance of the algorithm deteriorates drastically for large maneuvers if actuator saturation is not accounted for. Four methods of command limiting are proposed to handle the problem, which are based on a scaling of the control inputs, a relaxation of the control requirements, a scaling of the reference inputs, and a least-squares approximation of the commanded accelerations. Simulations demonstrate the effectiveness of the algorithms in the reconfigurable flight control application. Even the simplest method is found to considerably improve the responses, and, surprisingly, the performance of all four methods is similar despite their widely different concepts and complexity levels. In some cases, degraded transient responses are observed, which are attributed to the uncertainty in the aircraft parameters following a failure.

关键词： Digital Flight Control Control Surfaces Actuators Model Reference Adaptive Control Elevator Deflection Pilot recursive algorithm Pitching Moment Stabilator Dryden Flight Research Center

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SIMULTANEOUS COEFFICIENT ASSIGNMENT OF DISCRETE-TIME MULTIINPUT MULTIOUTPUT LINEAR TIME-VARYING SYSTEM - A NEW APPROACH FOR COMPENSATOR DESIGN

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SIAM JOURNAL ON CONTROL AND OPTIMIZATION 1993年第6期31卷 1438-1461页

作者： GHOSH, BK BOUTHELLIER, PR Washington Univ Saint Louis MO USA

In this paper, a linear time-varying input-output system is considered and its realization as a linear time-varying autoregressive moving average system (ARMA) is studied. A time-varying z-transform is also introduced and its properties are studied. Furthermore a time-varying version of the coefficient assignment problem well known in time invariant system theory as the pole placement problem is posed and analyzed. A r-tuple of discrete time, linear time-varying plants with m inputs and p outputs are considered together with a single p input m output linear time-varying compensator. The design objective is to construct a single compensator thar ''coefficient assigns,'' and hence ''bounded input bounded output stabilizes'' under suitable additional technical assumptions, the set of r plants simultaneously in the closed loop. Such a problem is useful in robust design of linear time-varying control systems in the closed loop. Among the results, it is shown that a generic r-tuple of p x m plants (in a suitable topology) is simultaneously coefficient assignable, provided that r < m/p. The design procedure involves splitting the closed-loop system into an ARMA system in cascade with a moving average system. The coefficient assignment problem consists of assigning the coefficients of the autoregressive part of the ARMA subsystem. Thereby an algorithm is obtained that is nonrecursive and involves solving for each time instant a system of linear equations with time-varying coefficients. The associated time-varying matrix has the ''Sylvester matrix structure.'' Such a structure is well-known in pole placement of time-invariant systems by dynamic compensation. Additionally the problem of coefficient assignment of the autoregressive part of the ARMA system is considered in the closed loop, without splitting up into a cascade of two subsystems as before. A new recursive algorithm to analyze this problem has been introduced. The proposed algorithm has no counterpart in the time-i

关键词： COEFFICIENT ASSIGNMENT recursive algorithm SIMULTANEOUS DESIGN TIME-VARYING SYSTEM CHAOTIC DYNAMICS

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Reliability of a toroidal connected-(r,s)-out-of-(m,n):F lattice system

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART O-JOURNAL OF RISK AND RELIABILITY 2022年第2期236卷 329-338页

作者： Nakamura, Taishin Yamamoto, Hisashi Akiba, Tomoaki Tokyo Metropolitan Univ Grad Sch Syst Design Hachioji Tokyo 1920397 Japan Chiba Inst Technol Fac Social Syst Sci Chiba Japan

This article focuses on a toroidal connected-(r,s)-out-of-(m,n):F lattice system, which has m vertical circles and n horizontal circles, and the components are deployed at their intersections. This system fails if and only if the system has an (r,s) sub-matrix where all components fail. It might be used to evaluate the reliability of a system with a toroidal structure, for example, toroidal storage tanks and neutron accelerators. The purpose of this article is to efficiently compute the reliability of the toroidal connected-(r,s)-out-of-(m,n):F lattice system. First, we propose a recursive method and then develop two kinds of algorithms based on this method. We apply an idea of preparing a set in a pre-processing phase to one algorithm, and consequently, the algorithm with the idea requires the extra memory space but has better time complexity compared with the other one. Finally, we investigate the efficiency of the two algorithms through numerical experiments.

关键词： Connected-(r,s)-out-of-(m,n):F lattice system toroidal connected-(r,s)-out-of-(m,n):F lattice system system reliability evaluation recursive algorithm

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A method for calculating probability convolution using "ternary" numbers with application in the determination of twin zygosity

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COMPUTATIONAL STATISTICS & DATA ANALYSIS 1998年第2期28卷 225-232页

作者： Zhao, JH Sham, PC Inst Psychiat Dept Psychol Med London SE5 8AF England Inst Psychiat Dept Biostat & Comp London SE5 8AF England

It often happens that an efficient algorithm can be designed by considering some special properties of the problem. In this short paper we describe a problem in twin zygosity determination that involves a convolution of probability distributions. Our solution to this problem was to develop an algorithm for counting in the base-3 or "ternary" number system. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

关键词： trinary numbers twin zygosity recursive algorithm

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Hybrid neural network predictor for distributed parameter system based on nonlinear dimension reduction

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NEUROCOMPUTING 2016年 171卷 1591-1597页

作者： Wang, Mengling Qi, Chenkun Yan, Huaicheng Shi, Hongbo E China Univ Sci & Technol Minist Educ Key Lab Adv Control & Optimizat Chem Proc Shanghai 200237 Peoples R China Shanghai Jiao Tong Univ Sch Mech Engn Shanghai 200030 Peoples R China

In this study, a hybrid neural network predictor is proposed to predict spatiotemporal dynamics of the nonlinear distributed parameter systems (DPSs) with unwanted disturbance or slow set point changes. First, a nonlinear principal component analysis (NL-PCA) network is designed to transform the high-dimensional spatiotemporal data into a low-dimensional time domain, which can better represent the nonlinearity of the system compared to the linear time/space separation method. Then the hybrid NN models are built to identify the low-dimensional temporal data. To capture the spatiotemporal dynamics of DPS, the four-step recursive algorithm is used to obtain the time-varying weights of the model, while the parameters of NN model does not need to online update. The simulations demonstrated show that the proposed approach can achieve a good performance on prediction with system slow time-varying dynamics. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Neural network Nonlinear parabolic distributed parameter system Nonlinear dimension reduction recursive algorithm

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Cooperative Trajectory Generation Using Pythagorean Hodograph Bezier Curves

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2016年第8期39卷 1744-1763页

作者： Choe, Ronald Puig-Navarro, Javier Cichella, Venanzio Xargay, Enric Hovakimyan, Naira Univ Illinois Dept Aerosp Engn Urbana IL 61801 USA Univ Illinois Dept Mech Sci & Engn Urbana IL 61801 USA

This paper presents a cooperative trajectory-generation framework to efficiently compute a set of spatial trajectories for a team of cooperating vehicles: in particular, for unmanned aerial vehicles. The desired, feasible trajectories are generated using Pythagorean Hodograph Bezier curves, satisfy stringent spatial and temporal constraints, do not violate the dynamic constraints of the vehicles, and guarantee spatial deconfliction between the trajectories for safe operation. A multivehicle mission scenario is presented to show the efficacy of the proposed cooperative trajectory-generation framework.

关键词： Unmanned System Flight Path Angle Pseudospectral Optimal Control Model Predictive Control Fixed Wing Aircraft Computing Power MATLAB Mixed Integer Linear Programming recursive algorithm Motion Planning

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