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非线性模型下的摄像机自标定 被引量:16
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作者 吴福朝 阮宗才 胡占义 《计算机学报》 EI CSCD 北大核心 2002年第3期276-283,共8页
摄像机标定是从二维图像获取三维信息必不可少的步骤 .线性 (小孔 )模型摄像机自标定 ,目前已成为计算机视觉领域的研究热点之一 .对于非线性模型下摄像机的自标定 ,目前还未见到相关的研究报道 .由于线性模型一般不能准确地描述真实摄... 摄像机标定是从二维图像获取三维信息必不可少的步骤 .线性 (小孔 )模型摄像机自标定 ,目前已成为计算机视觉领域的研究热点之一 .对于非线性模型下摄像机的自标定 ,目前还未见到相关的研究报道 .由于线性模型一般不能准确地描述真实摄像机的几何成像关系 ,因此对非线性模型摄像机自标定的研究具有十分重要的实际意义 .该文主要探索非线性模型摄像机的自标定方法 .基本原理是将非线性模型视为线性模型和畸变项的叠加 ,然后利用线性模型的基本矩阵或单应矩阵 ,给出非线性模型参数的约束方程 ,从而实现非线性模型摄像机的自标定 .模拟和真实图像实验均表明该文所给的方法是可行的 。 展开更多
关键词 非线线模型 摄像机目标定 基本矩阵 单应矩阵 计算机视觉
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Study on Growth and Development Rules and Growth Curve Fitting of Minghua Black Minks
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作者 荣敏 涂剑锋 +3 位作者 张志明 王淑茗 高峰 邢秀梅 《Agricultural Science & Technology》 CAS 2017年第2期285-286,302,共3页
Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very w... Growth curves of Minghua black minks at 0-180 days old were fitted and analyzed by using two growth models Logistic and Gompertz. The results showed that the growth curves of Minghua black minks could be fitted very well by Logistic model and Gompertz model (the degree of fitting FF≥0.99), but Gompertz model was better at fitting and predicting their weight. 展开更多
关键词 Minghua black minks Growth curve Non-lineared models Development rules FITTING
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Support vector machine based nonlinear model multi-step-ahead optimizing predictive control 被引量:9
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作者 钟伟民 皮道映 孙优贤 《Journal of Central South University of Technology》 EI 2005年第5期591-595,共5页
A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established... A support vector machine with guadratic polynomial kernel function based nonlinear model multi-step-ahead optimizing predictive controller was presented. A support vector machine based predictive model was established by black-box identification. And a quadratic objective function with receding horizon was selected to obtain the controller output. By solving a nonlinear optimization problem with equality constraint of model output and boundary constraint of controller output using Nelder-Mead simplex direct search method, a sub-optimal control law was achieved in feature space. The effect of the controller was demonstrated on a recognized benchmark problem and a continuous-stirred tank reactor. The simulation results show that the multi-step-ahead predictive controller can be well applied to nonlinear system, with better performance in following reference trajectory and disturbance-rejection. 展开更多
关键词 nonlinear model predictive control support vector machine nonlinear system identification kernel function nonlinear optimization
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Low-speed instability analysis for hydraulic motor based on nonlinear dynamics 被引量:4
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作者 LIN Rong-chuan WEI Sha-sha YUAN Xiao-ling 《Journal of Coal Science & Engineering(China)》 2010年第3期328-332,共5页
A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major fac... A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major factors that can affect low-speed instability.The mathematic model was established to obtain the change rule of speed andinstantaneous acceleration of the hydraulic motor.Then, Matlab was used to simulate theeffect of nonlinear friction force and hydraulic motor parameters such as coefficient of leakand compression ratio, etc., under low speed.Finally, some measures were proposed toimprove the low-speed stability of the hydraulic motor. 展开更多
关键词 hydraulic motor nonlinear dynamics hydraulic spring vibration creep accel- eration computer simulation
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Multi-domain modeling and simulation of proportional solenoid valve 被引量:3
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作者 刘艳芳 戴振坤 +1 位作者 徐向阳 田亮 《Journal of Central South University》 SCIE EI CAS 2011年第5期1589-1594,共6页
A multi-domain nonlinear dynamic model of a proportional solenoid valve was presented.The electro-magnetic,mechanical and fluid subsystems of the valve were investigated,including their interactions.Governing equation... A multi-domain nonlinear dynamic model of a proportional solenoid valve was presented.The electro-magnetic,mechanical and fluid subsystems of the valve were investigated,including their interactions.Governing equations of the valve were derived in the form of nonlinear state equations.By comparing the simulated and measured data,the simulation model is validated with a deviation less than 15%,which can be used for the structural design and control algorithm optimization of proportional solenoid valves. 展开更多
关键词 fluid mechanics proportional solenoid valve dynamic characteristic multi-domain modeling SIMULATION
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Nonlinear correction of photoelectric displacement sensor based on least square support vector machine 被引量:1
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作者 郭杰荣 何怡刚 刘长青 《Journal of Central South University》 SCIE EI CAS 2011年第5期1614-1618,共5页
A model of correcting the nonlinear error of photoelectric displacement sensor was established based on the least square support vector machine.The parameters of the correcting nonlinear model,such as penalty factor a... A model of correcting the nonlinear error of photoelectric displacement sensor was established based on the least square support vector machine.The parameters of the correcting nonlinear model,such as penalty factor and kernel parameter,were optimized by chaos genetic algorithm.And the nonlinear correction of photoelectric displacement sensor based on least square support vector machine was applied.The application results reveal that error of photoelectric displacement sensor is less than 1.5%,which is rather satisfactory for nonlinear correction of photoelectric displacement sensor. 展开更多
关键词 least square support vector machine POSITION photoelectric displacement sensor nonlinear correct
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Nonlinear flow numerical simulation of low-permeability reservoir 被引量:2
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作者 于荣泽 卞亚南 +3 位作者 周舒 王楷军 吕琦 陈朝辉 《Journal of Central South University》 SCIE EI CAS 2012年第7期1980-1987,共8页
A nonlinear flow reservoir mathematical model was established based on the flow characteristic of low-permeability reservoir.The well-grid equations were deduced and the dimensionless permeability coefficient was intr... A nonlinear flow reservoir mathematical model was established based on the flow characteristic of low-permeability reservoir.The well-grid equations were deduced and the dimensionless permeability coefficient was introduced to describe the permeability variation of nonlinear flow.The nonlinear flow numerical simulation program was compiled based on black-oil model.A quarter of five-spot well unit was simulated to study the effect of nonlinear flow on the exploitation of low-permeability reservoir.The comprehensive comparison and analysis of the simulation results of Darcy flow,quasi-linear flow and nonlinear flow were provided.The dimensionless permeability coefficient distribution was gained to describe the nonlinear flow degree.The result shows that compared with the results of Darcy flow,when considering nonlinear flow,the oil production is low,and production decline is rapid.The fluid flow in reservoir consumes more driving energy,which reduces the water flooding efficiency.Darcy flow model overstates the reservoir flow capability,and quasi-linear flow model overstates the reservoir flow resistance.The flow ability of the formation near the well and artificial fracture is strong while the flow ability of the formation far away from the main streamline is weak.The nonlinear flow area is much larger than that of quasi-linear flow during the fluid flow in low-permeability reservoir.The water propelling speed of nonlinear flow is greatly slower than that of Darcy flow in the vertical direction of artificial fracture,and the nonlinear flow should be taken into account in the well pattern arrangement of low-permeability reservoir. 展开更多
关键词 low-permeability reservoir nonlinear flow mathematical model numerical simulation
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A multi-objective model for cordon-based congestion pricing schemes with nonlinear distance tolls 被引量:1
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作者 孙鑫 刘志远 +3 位作者 THOMPSON Russell G 别一鸣 翁金贤 陈淑燕 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1273-1282,共10页
Congestion pricing is an important component of urban intelligent transport system.The efficiency,equity and the environmental impacts associated with road pricing schemes are key issues that should be considered befo... Congestion pricing is an important component of urban intelligent transport system.The efficiency,equity and the environmental impacts associated with road pricing schemes are key issues that should be considered before such schemes are implemented.This paper focuses on the cordon-based pricing with distance tolls,where the tolls are determined by a nonlinear function of a vehicles' travel distance within a cordon,termed as toll charge function.The optimal tolls can give rise to:1) higher total social benefits,2) better levels of equity,and 3) reduced environmental impacts(e.g.,less emission).Firstly,a deterministic equilibrium(DUE) model with elastic demand is presented to evaluate any given toll charge function.The distance tolls are non-additive,thus a modified path-based gradient projection algorithm is developed to solve the DUE model.Then,to quantitatively measure the equity level of each toll charge function,the Gini coefficient is adopted to measure the equity level of the flows in the entire transport network based on equilibrium flows.The total emission level is used to reflect the impacts of distance tolls on the environment.With these two indexes/measurements for the efficiency,equity and environmental issues as well as the DUE model,a multi-objective bi-level programming model is then developed to determine optimal distance tolls.The multi-objective model is converted to a single level model using the goal programming.A genetic algorithm(GA) is adopted to determine solutions.Finally,a numerical example is presented to verify the methodology. 展开更多
关键词 distance-based toll charging schemes EQUITY path-based gradient projection algorithm non-additive goal programming
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Collapse Analysis of Imperfect Subsea Pipelines Based on 2D High-Order Nonlinear Model 被引量:3
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作者 余建星 李智博 +1 位作者 杨源 孙震洲 《Transactions of Tianjin University》 EI CAS 2014年第3期157-162,共6页
To study the collapse of imperfect subsea pipelinos, a 2D high-order nonlinear model is developed. In this model, the large deformation of the pipes is considered by raiaining the high-order nonlinear terms of strain.... To study the collapse of imperfect subsea pipelinos, a 2D high-order nonlinear model is developed. In this model, the large deformation of the pipes is considered by raiaining the high-order nonlinear terms of strain. In addi-tion, the J2 plastic flow theory is adopted to describe the elasioplastic constitutive relations of material. The quasi-static process of collapse is analyzed by the increment method. For each load step, the equations based on the principle of virtual work are presented and solved by the discrete Newton's method. Furthermore, finite element simulations and full-scale experiments were preformed to validate the results of the model. Research on the major influencing factors of collapse pressure, including D/t, material type and initial ovality, is also presented. 展开更多
关键词 IMPERFECTION subsea pipelines COLLAPSE NONLINEARITY initial ovality
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Regression model for daily passenger volume of high-speed railway line under capacity constraint 被引量:2
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作者 骆泳吉 刘军 +1 位作者 孙迅 赖晴鹰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第9期3666-3676,共11页
A non-linear regression model is proposed to forecast the aggregated passenger volume of Beijing-Shanghai high-speed railway(HSR) line in China. Train services and temporal features of passenger volume are studied to ... A non-linear regression model is proposed to forecast the aggregated passenger volume of Beijing-Shanghai high-speed railway(HSR) line in China. Train services and temporal features of passenger volume are studied to have a prior knowledge about this high-speed railway line. Then, based on a theoretical curve that depicts the relationship among passenger demand, transportation capacity and passenger volume, a non-linear regression model is established with consideration of the effect of capacity constraint. Through experiments, it is found that the proposed model can perform better in both forecasting accuracy and stability compared with linear regression models and back-propagation neural networks. In addition to the forecasting ability, with a definite formation, the proposed model can be further used to forecast the effects of train planning policies. 展开更多
关键词 high-speed rail Jinghu high-speed railway(HSR) DEMAND capacity forecasting
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Generalized Nonlinear Irreducible Auto-Correlation and Its Applications in Nonlinear Prediction Models Identification
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作者 侯越先 何丕廉 《Transactions of Tianjin University》 EI CAS 2005年第1期35-39,共5页
There is still an obstacle to prevent neural network from wider and more effective applications, i.e., the lack of effective theories of models identification. Based on information theory and its generalization, this ... There is still an obstacle to prevent neural network from wider and more effective applications, i.e., the lack of effective theories of models identification. Based on information theory and its generalization, this paper introduces a universal method to achieve nonlinear models identification. Two key quantities, which are called nonlinear irreducible auto-correlation (NIAC) and generalized nonlinear irreducible auto-correlation (GNIAC), are defined and discussed. NIAC and GNIAC correspond with intrinstic irreducible auto-(dependency) (IAD) and generalized irreducible auto-(dependency) (GIAD) of time series respectively. By investigating the evolving trend of NIAC and GNIAC, the optimal auto-regressive order of nonlinear auto-regressive models could be determined naturally. Subsequently, an efficient algorithm computing NIAC and GNIAC is discussed. Experiments on simulating data sets and typical nonlinear prediction models indicate remarkable correlation between optimal auto-regressive order and the highest order that NIAC-GNIAC have a remarkable non-zero value, therefore demonstrate the validity of the proposal in this paper. 展开更多
关键词 prediction models identification information entropy Tsallis entropy neural networks nonlinear irreducible autocorrelation generalized nonlinear irreducible autocorrelation
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Parameter estimation of cutting tool temperature nonlinear model using PSO algorithm
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作者 刘益剑 张建明 王树青 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第10期1026-1029,共4页
In cutting tool temperature experiment, a large number of related data could be available. In order to define the relationship among the experiment data, the nonlinear regressive curve of cutting tool temperature must... In cutting tool temperature experiment, a large number of related data could be available. In order to define the relationship among the experiment data, the nonlinear regressive curve of cutting tool temperature must be constructed based on the data. This paper proposes the Particle Swarm Optimization (PSO) algorithm for estimating the parameters such a curve. The PSO algorithm is an evolutional method based on a very simple concept. Comparison of PSO results with those of GA and LS methods showed that the PSO algorithm is more effective for estimating the parameters of the above curve. 展开更多
关键词 Particle Swarm Optimization (PSO) Cutting tool Parameter estimation Temperature nonlinear model
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Nonlinear Model Algorithmic Control of a pH Neutralization Process 被引量:11
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作者 邹志云 于蒙 +4 位作者 王志甄 刘兴红 郭宇晴 张风波 郭宁 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第4期395-400,共6页
Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinea... Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors. 展开更多
关键词 model algorithmic control nonlinear model predictive control Hammerstein model pH neutralization process control simulation
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Linear and Non-linear Hydrodynamic Analysis for Structural Load of a Pipe-Laying Ship
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作者 Frank Lin 《Journal of Shipping and Ocean Engineering》 2012年第1期1-9,共9页
The first decision we need to make in a structural load assessment is what approach should be applied, a linear approach or a non-linear one. The correct decision comes from understanding of the technology used in the... The first decision we need to make in a structural load assessment is what approach should be applied, a linear approach or a non-linear one. The correct decision comes from understanding of the technology used in the linear and non-linear approaches and also comes from the understanding of the problem to he analyzed. From engineering practice, it has been found that many non-linear effects can be taken into account in a linear model with appropriate approach. A study of hydrodynamic structural load on a stinger of a pipe-laying vessel is presented in this paper. The results of a non-linear analysis are compared to those of linear models with different approaches, and how the nonlinear effect can be involved in a linear model is discussed. The recommendations on how to estimate the non-linear effects in a linear structural load model is discussed. 展开更多
关键词 Non-linear effect linear model design load stinger-ship interaction.
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Local Partial Least Squares Based Online Soft Sensing Method for Multi-output Processes with Adaptive Process States Division 被引量:3
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作者 邵伟明 田学民 王平 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第7期828-836,共9页
Local learning based soft sensing methods succeed in coping with time-varying characteristics of processes as well as nonlinearities in industrial plants. In this paper, a local partial least squares based soft sensin... Local learning based soft sensing methods succeed in coping with time-varying characteristics of processes as well as nonlinearities in industrial plants. In this paper, a local partial least squares based soft sensing method for multi-output processes is proposed to accomplish process states division and local model adaptation,which are two key steps in development of local learning based soft sensors. An adaptive way of partitioning process states without redundancy is proposed based on F-test, where unique local time regions are extracted.Subsequently, a novel anti-over-fitting criterion is proposed for online local model adaptation which simultaneously considers the relationship between process variables and the information in labeled and unlabeled samples. Case study is carried out on two chemical processes and simulation results illustrate the superiorities of the proposed method from several aspects. 展开更多
关键词 Local learning Online soft sensing Partial least squares F-TEST Multi-output process Process state division
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Modelling and Vibration of Gear Drive Systems Influenced by Real Face Width
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作者 Miroslav Byrtus Vladimir Zeman 《Journal of Mechanics Engineering and Automation》 2013年第12期721-730,共10页
Gear drives are one of the most common parts in many rotating machinery. If the gear drive runs under lower torque load, nonlinear effects like gear mesh interruption can occur and vibration is accompanied by impact m... Gear drives are one of the most common parts in many rotating machinery. If the gear drive runs under lower torque load, nonlinear effects like gear mesh interruption can occur and vibration is accompanied by impact motions of the gears, This paper presents an original method of the mathematical modelling of gear drive nonlinear vibrations by using the modal synthesis method with degrees of freedom number reduction. The model respects nonlinearities caused by gear mesh interruption, parametric gearing excitation caused by time-varying meshing stiffness and nonlinear contact forces acting between journals of the rolling-element bearings and the outer housing. The nonlinear model is then used for investigation of gear drive vibration, especially for constant gear mesh determination. The theoretical method is applied for investigating of test gear drive nonlinear vibration. 展开更多
关键词 Nonlinear vibration rotating systems nonlinear gear and bearing couplings parametric excitation modal synthesismethod action plane.
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A practical nonlinear controller for levitation system with magnetic flux feedback 被引量:4
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作者 李金辉 李杰 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第7期1729-1739,共11页
This work proposes a practical nonlinear controller for the MIMO levitation system. Firstly, the mathematical model of levitation modules is developed and the advantages of the control scheme with magnetic flux feedba... This work proposes a practical nonlinear controller for the MIMO levitation system. Firstly, the mathematical model of levitation modules is developed and the advantages of the control scheme with magnetic flux feedback are analyzed when compared with the current feedback. Then, a backstepping controller with magnetic flux feedback based on the mathematical model of levitation module is developed. To obtain magnetic flux signals for full-size maglev system, a physical method with induction coils installed to winding of the electromagnet is developed. Furthermore, to avoid its hardware addition, a novel conception of virtual magnetic flux feedback is proposed. To demonstrate the feasibility of the proposed controller, the nonlinear dynamic model of full-size maglev train with quintessential details is developed. Based on the nonlinear model, the numerical comparisons and related experimental validations are carried out. Finally, results illustrating closed-loop performance are provided. 展开更多
关键词 MAGLEV levitation system BACKSTEPPING magnetic flux
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Nonlinear model predictive control with guaranteed stability based on pseudolinear neural networks
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作者 WANGYongji WANGHong 《Journal of Chongqing University》 CAS 2004年第1期26-29,共4页
A nonlinear model predictive control problem based on pseudo-linear neural network (PNN) is discussed, in which the second order on-line optimization method is adopted. The recursive computation of Jacobian matrix is ... A nonlinear model predictive control problem based on pseudo-linear neural network (PNN) is discussed, in which the second order on-line optimization method is adopted. The recursive computation of Jacobian matrix is investigated. The stability of the closed loop model predictive control system is analyzed based on Lyapunov theory to obtain the sufficient condition for the asymptotical stability of the neural predictive control system. A simulation was carried out for an exothermic first-order reaction in a continuous stirred tank reactor.It is demonstrated that the proposed control strategy is applicable to some of nonlinear systems. 展开更多
关键词 pseudolinear neural networks (PNN) nonlinear model predictive control continuous stirred tank reactor (CSTR) asymptotic stability
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Modeling and control for hydraulic transmission of unmanned ground vehicle 被引量:1
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作者 王岩 张泽 秦绪情 《Journal of Central South University》 SCIE EI CAS 2014年第1期124-129,共6页
Variable pump driving variable motor(VPDVM) is the future development trend of the hydraulic transmission of an unmanned ground vehicle(UGV).VPDVM is a dual-input single-output nonlinear system with coupling,which is ... Variable pump driving variable motor(VPDVM) is the future development trend of the hydraulic transmission of an unmanned ground vehicle(UGV).VPDVM is a dual-input single-output nonlinear system with coupling,which is difficult to control.High pressure automatic variables bang-bang(HABB) was proposed to achieve the desired motor speed.First,the VPDVM nonlinear mathematic model was introduced,then linearized by feedback linearization theory,and the zero-dynamic stability was proved.The HABB control algorithm was proposed for VPDVM,in which the variable motor was controlled by high pressure automatic variables(HA) and the variable pump was controlled by bang-bang.Finally,simulation of VPDVM controlled by HABB was developed.Simulation results demonstrate the HABB can implement the desired motor speed rapidly and has strong robustness against the variations of desired motor speed,load and pump speed. 展开更多
关键词 unmanned ground vehicle HYDRAULIC nonlinear system high pressure automatic variables bang-bang
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Modeling and optimization methods of integrated production planning for steel plate mill with flexible customization 被引量:1
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作者 卢山 苏宏业 +2 位作者 Charlotta Johnsson 王越 谢磊 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第12期2037-2047,共11页
With diversified requirements and varying manufacturing environments, the optimal production planning for a steel mill becomes more flexible and complicated. The flexibility provides operators with auxiliary requireme... With diversified requirements and varying manufacturing environments, the optimal production planning for a steel mill becomes more flexible and complicated. The flexibility provides operators with auxiliary requirements through an implementable integrated production planning. In this paper, a mixed-integer nonlinear programming(MINLP) model is proposed for the optimal planning that incorporates various manufacturing constraints and flexibility in a steel plate mill. Furthermore, two solution strategies are developed to overcome the weakness in solving the MINLP problem directly. The first one is to transform the original MINLP formulation to an approximate mixed integer linear programming using a classic linearization method. The second one is to decompose the original model using a branch-and-bound based iterative method. Computational experiments on various instances are presented in terms of the effectiveness and applicability. The result shows that the second method performs better in computational efforts and solution accuracy. 展开更多
关键词 Production planning Steel plate mill Flexibility Mixed integer nonlinear programming
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