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Application of hybrid robotic systems in crop harvesting: Kinematic and dynamic analysis

COMPUTERS AND ELECTRONICS IN AGRICULTURE 2023年 209卷

作者： Zahedi, A. Shafei, A. M. Shamsi, M. Shahid Bahonar Univ Kerman Dept Mech Biosyst Kerman Iran Shahid Bahonar Univ Kerman Dept Mech Engn Kerman Iran

Harvesting of agricultural crops, especially when the ripe products have to be picked one by one, has always been a major concern of farmers and growers. Consequently, the use of robots and the mechanization of harvesting operations have been considered as the effective means of tackling such challenges. In the present research, the use of hybrid robots (which combine open-loop and closed-loop manipulators) has been proposed for this purpose;because these robots help reduce the size of the workforce and thus slash the harvesting costs, and they also boost the speed and accuracy of harvesting operations. However, using this type of robots without paying attention to some important factors (e.g., using motors of optimal power at the actuated joints of a robot and choosing appropriate lengths for robot links) can have a substantial adverse effect on the manufacturing cost, working space and the effective functioning of such robots. So the main focus of this paper is on the kinematic and dynamic analysis of hybrid robotic systems. The main advantage of this research over similar works is the generality by which it describes the mechanical behavior of these robots;so that by using the recursive algorithms presented in this paper, all kinds of robots in the hybrid class can be analyzed. However, due to the complexity in the analysis of such systems, a hybrid robot consisting of three closed loops and one open loop was considered in this paper as a sample case study, so that we could explain, visually and graphically, all the steps involved in deriving its motion equations. The simulation results for this robotic system demonstrate the efficacy of the proposed method in the kinematic and dynamic analysis of hybrid robots, as efficient and functional crop harvesting equipment.

关键词： Hybrid robots Agricultural applications Kinematic analysis Kinetic Analysis recursive algorithm

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A flexible optimization algorithm for GO-FLOW methodology to deal with shared signals

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ANNALS OF NUCLEAR ENERGY 2021年 156卷

作者： Zheng, Licheng Dai, Xinyu Yang, Jun Yang, Ming Lu, Hongxing South China Univ Technol Sch Elect Power Engn 381 Wushan Rd Guangzhou 510640 Peoples R China Harbin Engn Univ Coll Nucl Sci & Technol 145 Nantong St Harbin 150001 Peoples R China Shenzhen Univ Coll Phys & Optoelect Engn Shenzhen Peoples R China

In this paper, we propose an optimized GO-FLOW algorithm for time-dependent system reliability analysis. The optimized GO-FLOW algorithm is implemented based on recursive calculation of the complete set of minimum path sets. The algorithm is augmented with a cut-off criterion for probabilistic models to offer a much more flexible approach to achieve the trade-off between computational complexity and accuracy. The optimization method and algorithm are tested with an example case study of reliability analysis of auxiliary feedwater system in nuclear power plants. The verification results show that the retrofitting GO-FLOW method is capable of efficient processing of the shared signals and providing accuracy solutions at high speed. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Reliability analysis GO-FLOW methodology Shared signal recursive algorithm

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CONTACT DYNAMICS OF A SPHERICAL JOINT AND A JOINTED TRUSS-CELL SYSTEM

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AIAA JOURNAL 1991年第1期29卷 81-88页

作者： TZOU, HS RONG, Y University of Kentucky Lexington Kentucky 40506

This paper presents a mathematical modeling and stochastic simulation study of a three-dimensional spherical joint, a design feature of importance to a class of deployable space structures. An analytical model of the joint including friction and clearance effects is studied, and a system equation with time-variant coefficient matrices is then derived. A parametric study, including joint clearance size, joint rigidity/damping, and link elasticity/damping, of a jointed truss-cell model is investigated. The friction is assumed to be a normally distributed random variable and the external excitation is also treated random in a stochastic simulation study using an auto-regressive moving average (ARMA) model. This study shows that the joint dynamic contacts are affected by joint surface condition (stiffness/damping), joint clearance, link stiffness/damping, excitation, etc. Friction contacts dominate the system dynamics when the clearance is small and normal contacts dominate when the clearance is large.

关键词： Trusses Contact Dynamics Space Structures Mathematical Models Elasticity Damping Coefficient Coefficient of Friction Stiffness Matrices recursive algorithm Flexible Structures

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Modelling, performance evaluation and optimisation of (s, Q) retrial inventory system with partial backlogging demands: a GSPN approach

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EUROPEAN JOURNAL OF INDUSTRIAL ENGINEERING 2023年第4期17卷 529-569页

作者： Bazizi, Lydia Rahmoune, Fazia Lekadir, Ouiza Labadi, Karim Univ Bejaia Fac Exact Sci Res Unit LaMOS Modeling & Optimizat Syst Bejaia 06000 Algeria ECAM EPMI Quartz Lab Cergy Pontoise France

In this article, we model and analyse by using generalised stochastic Petri nets (GSPNs), an inventory system according to the (s, Q) replenishment policy, Poissonian batch arrivals in deterministic size n, immediate batch service and retrials. In out-of-stock situation, the arriving demands at the system join a limited orbit, if it is not full, and retry again after a random time exponentially distributed, following the classic retrial policy. However, in the case of a full orbit, these demands are definitively rejected from the system. We describe the dynamic of this inventory system using a two-dimensional continuous time Markov chain (CTMC), which expresses the inventory level and the number of demands in the orbit. Then, we recover the stationary distribution, using a recursive algorithm, from which we derive various performance measures. Finally, we investigate some numerical analysis of the reward-cost function induced by this model.

关键词： inventory control system (s, Q) policy generalised stochastic Petri nets GSPNs continuous time Markov chain CTMC recursive algorithm reward-cost function

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A NEW recursive FORMULATION FOR FAST ESTIMATION OF TIME-VARYING UNKNOWN INPUT. APPLICATION FOR ESTIMATING A PARTICLE ACCELERATION

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INTERNATIONAL JOURNAL OF INNOVATIVE COMPUTING INFORMATION AND CONTROL 2011年第7A期7卷 3779-3797页

作者： Sircoulomb, Vincent Hoblos, Ghaleb Chafouk, Houcine Ragot, Jose Inst Rech Syst Elect EMbarques EA 4353 F-76801 St Etienne France Inst Natl Polytech Lorraine CRAN CNRS UMR 7039 F-54516 Vandoeuvre Les Nancy France

This paper proposes an extension of the recursive Input Estimation (RIE) for estimating time-varying unknown input. This extension is based on modifications of the Least Squares (LS) algorithm of the RIE, which increase its capability to track time varying unknown input. These modifications consist in inserting a forgetting factor into the LS algorithm and adding an integral effect. Moreover, alternative formulations are proposed, allowing the reduction of computation time in the case where the number of inputs to estimate is lower than the number of measurements. The different tools obtained are tested and compared on a three-dimensional tracking application.

关键词： Unknown input estimation Kalman filtering Least squares recursive algorithm Integral effect Computation Tracking

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recursive Identification of Continuous Two-Dimensional Systems in the Presence of Additive Colored Noise

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IETE JOURNAL OF RESEARCH 2014年第1期60卷 74-84页

作者： Shafieirad, Mohsen Shafiee, Masoud Abedi, Mehrdad Amirkabir Univ Technol Dept Elect Engn Tehran Iran Amirkabir Univ Technol SIC Res Inst Tehran Iran

In this paper, a recursive algorithm is developed to estimate the parameters of a partial differential equation as a continuous two-dimensional (2-D) system in the presence of additive colored noise. The system is modelled as hybrid Box-Jenkins model. No comprehensive algorithm for identification of continuous 2-D systems simultaneous with noise process parameter estimation has been proposed so far. Also, there is no recursive method to identify the continuous 2-D systems. The proposed algorithm estimates the noise-free system parameters and colored noise process parameters based on the instrumental variable method simultaneously. Finally, the performance of the proposed method is evaluated by a numerical example.

关键词： Two-dimensional continuous systems recursive algorithm Instrumental variable Stochastic estimation

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A fast algorithm for multilevel thresholding

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2001年第5期17卷 713-727页

作者： Liao, PS Chew, TS Chung, PC ChengShiu Inst Technol Dept Elect Engn Kaohsiung 833 Taiwan Natl Cheng Kung Univ Dept Engn Sci Tainan 701 Taiwan Natl Cheng Kung Univ Dept Elect Engn Tainan 701 Taiwan

Otsu reference proposed a criterion for maximizing the between-class variance of pixel intensity to perform picture thresholding. However, Otsu's method for image segmentation is very time-consuming because of the inefficient formulation of the between-class variance. In this paper, a faster version of Otsu's method is proposed for improving the efficiency of computation for the optimal thresholds of an image. First, a criterion for maximizing a modified between-class variance that is equivalent to the criterion of maximizing the usual between-class variance is proposed for image segmentation. Next, in accordance with the new criterion, a recursive algorithm is designed to efficiently find the optimal threshold. This procedure yields the same set of thresholds as the original method. In addition, the modified between-class variance can be pre-computed and stored in a look-up table. Our analysis of the new criterion clearly shows that it takes less computation to compute both the cumulative probability (zeroth order moment) and the mean (first order moment) of a class, and that determining the modified between-class variance by accessing a look-up table is quicker than that by performing mathematical arithmetic operations. For example, the experimental results of a five-level threshold selection show that our proposed method can reduce down the processing time from more than one hour by the conventional Otsu's method to less than 107 seconds.

关键词： Otsu's thresholding image segmentation picture thresholding multilevel thresholding recursive algorithm

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APPROXIMATION OF A LINEAR DYNAMIC PROCESS MODEL USING THE FREQUENCY APPROACH AND A NON-QUADRATIC MEASURE OF THE MODEL ERROR

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INTERNATIONAL JOURNAL OF APPLIED MATHEMATICS AND COMPUTER SCIENCE 2014年第1期24卷 99-109页

作者： Janiszowski, Krzysztof B. Warsaw Univ Technol Inst Automat Control & Robot PL-02525 Warsaw Poland

The paper presents a novel approach to approximation of a linear transfer function model, based on dynamic properties represented by a frequency response, e. g., determined as a result of discrete-time identification. The approximation is derived for minimization of a non-quadratic performance index. This index can be determined as an exponent or absolute norm of an error. Two algorithms for determination of the approximation coefficients are considered, a batch processing one and a recursive scheme, based on the well-known on-line identification algorithm. The proposed approach is not sensitive to local outliers present in the original frequency response. Application of the approach and its features are presented on examples of two simple dynamic systems.

关键词： approximation method frequency domain non-quadratic criterion recursive algorithm

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General class of tensegrity structures: Topology and prestress equilibrium analysis

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2003年第5期26卷 685-694页

作者： Williamson, D Skelton, RE Univ Wollongong Wollongong NSW 2522 Australia Univ Calif San Diego La Jolla CA 92093 USA

A general class of tensegrity structures, consisting of both compression members, that is, bars, and tensile members, that is, cables, is defined. For a given number N of bars, we define the topological structure that is necessary to establish a tensegrity. Necessary and sufficient conditions for prestress mechanical equilibria of the tensegrity are then provided in terms of a nonlinear function of the position and orientation of the bars and the rest lengths of the cables.

关键词： Tensegrity Structures Hooke's Law Mechanical Properties recursive algorithm

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Predictive avoidance for ground-based laser illumination

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JOURNAL OF SPACECRAFT AND ROCKETS 2000年第1期37卷 122-128页

作者： Alfano, S Burns, R Pohlen, D Wirsig, G US Space Command Peterson AFB CO 80914 USA USAF Res Lab Space Vehicles Directorate Kirtland AFB NM 87117 USA

Predictive avoidance determines discrete windows of time for safe laser illumination from a ground-based laser platform. That is, the analysis identifies time periods during which the laser will not inadvertently illuminate a satellite. The geometry of the problem is utilized to filter satellites that cannot possibly be illuminated by a specific laser platform. Further, several nongeometric filters are introduced to filter remaining satellites by removing those which cannot lie illuminated by the platform in a specified period. Both sets of filters improve the efficiency of the analysis by reducing the number of state propagations necessary. A method For determining the times of possible accidental illumination using cubic polynomial approximation is also presented. Finally, a test case is run that considers the entire catalog of objects publicly available from the U.S. Space Command. The complete analysis, which considers the entire catalog as potential victims for one target satellite pass, yields verified results in less than 3.5 s on a laptop personal computer running at 266 MHz.

关键词： Lasers Perigee Satellite Catalog Earth Air Force Space Command recursive algorithm Angular Motion Space Debris

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