In this paper, we have developed a new approach to determine a feedback control law of a nonlinear input affine system by the use of efficient mathematical tools: the Kronecker product, the non-redundant state formula...
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In this paper, we have developed a new approach to determine a feedback control law of a nonlinear input affine system by the use of efficient mathematical tools: the Kronecker product, the non-redundant state formulation and the polynomial representation of the transformation to a reference linear model, as well as a polynomial form of the control law. This method consists, as first step, in determining a polynomial transformation of coordinates to an equivalent linear model. Then, the synthesis of an analytic feedback control law via this nonlinear transformation has been presented in the second method step. The advantage of the proposed approach is the convenience of its implementation, as it copes with the complex differential geometric formalism of the exact linearization feedback control. To illustrate the efficiency of the presented approach, we have been applied it to a second order nonlinear model whose simulations results are presented.
A neural network model under the Bayesian framework (referred to as Bayesian neural network hereafter) is developed to predict the tensile strength of hot rolled products. The motivation of using a data-driven model i...
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A neural network model under the Bayesian framework (referred to as Bayesian neural network hereafter) is developed to predict the tensile strength of hot rolled products. The motivation of using a data-driven model is that in a modern steel mill, there exist huge online measurements and offline data, and can be exploited to extract the underlying relationships. The main advantage of using Bayesian neural network (BNN) is the robustness against over-fitting, thanks to the probabilistic reasoning behind the BNN. Preliminary modelling results are encouraging, and the properly trained BNN model can be used for online control and optimisation of the rolling mill to achieve desired mechanical properties.
Although neural networks (NN) are known to represent a powerful tool for mapping non-linear relationships between the inputs and outputs, their structures are typically set up by the modeller either by trial-and-error...
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Although neural networks (NN) are known to represent a powerful tool for mapping non-linear relationships between the inputs and outputs, their structures are typically set up by the modeller either by trial-and-error or based on their own experience. The latter is not only a time-consuming operation but also creates a risk that the best model structure is not necessarily selected. In this paper a genetic algorithm (GA) based strategy of determining the optimal NN-based model structure, together with the best training options for NN modelling will be described. Initial results of this GA-NN based modelling paradigm are promising, with the model performance being significantly improved when compared to previously elicited where the model structures were defined in an ‘ad-hoc’ fashion.
Data-driven modelling has gained much momentum recently, with modelling algorithms being evolved into more complex structures capable of dealing with highly non-linear multi-dimensional systems. However, it is widely ...
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Data-driven modelling has gained much momentum recently, with modelling algorithms being evolved into more complex structures capable of dealing with highly non-linear multi-dimensional systems. However, it is widely accepted that data-driven models are typically obtained under the principle of error minimisation, with the assumption of normal error distribution. The latter assumption is often not valid in more complex modelling environments, leading to sub-optimal model predictions. In this paper, a new modelling strategy aimed at exploiting the rich information contained in the model error data using a Gaussian mixture model (GMM) is proposed. The GMM error model can provide a probability characterisation of the error distribution, which can then be used complementally with the original data model. This combination often produces improvements in prediction performances, as will be illustrated in the case study relating to the hybrid modelling of the Charpy impact energy of heat-treated steels.
This paper introduces a new data granulation algorithm using significance weights on the input space of the data set. This data granulation algorithm aims to provide a more reliable way of grouping data together by di...
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This paper introduces a new data granulation algorithm using significance weights on the input space of the data set. This data granulation algorithm aims to provide a more reliable way of grouping data together by directing the data granulation to favor the most significant variables of the process under investigation. Such a data granulation algorithm assists in the elicitation of the initial rule-base of a fuzzy or neural-fuzzy model. A hybrid correlation index, called Significance Index, is introduced to rank the process variables based on the linear correlation coefficient and the partial correlation measure. The new algorithm is used to classify the process variables and subsequently model and predict mechanical properties of heat treated steel. The property under investigation is the Tensile Strength and the case study data set consists of chemical composition and microstructure measurements coupled with Tensile Strength measurements.
Defects-induced contact misalignment when combining embedded SiGe with flash lamp annealing (FLA) on high performance 40 nm CMOS process has been analyzed both by experiments and novel dislocation loop dynamics simula...
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Defects-induced contact misalignment when combining embedded SiGe with flash lamp annealing (FLA) on high performance 40 nm CMOS process has been analyzed both by experiments and novel dislocation loop dynamics simulation. We have found that slips which are created at the SiGe dummy patterns worsen the contact misalignment for the first time. Design guide lines on shape of SiGe patterns for slip free condition have been investigated and clarified. With optimized SiGe patterns, random component of contact misalignment have been successfully reduced to lead high SRAM yields at 40 nm tech node with high performance.
A possible area of applying new technology in food industry is food handling. Because food products vary even within the same product type, the most important step is the categorisation of different food goods. The im...
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A possible area of applying new technology in food industry is food handling. Because food products vary even within the same product type, the most important step is the categorisation of different food goods. The improved and novel food classification, which will be discussed in this paper, is unambiguous and it is able to interpret the categorisation table in an engineering way. The overall purpose of food categorisation is to allocate each category to a certain food process that describes physical structure from disarray. Having the mathematical algorithms that depend on the input disarray, the output array and the food product category appropriate and specialised equipment can be used to lead products into order. This can be described in a 3-dimensional matrix.
Operation of the gun/turret system in a military tank is limited by several constraints some of which are posed by obstacles existing on the vehicle's own platform. These mechanical constraints acting as hard cons...
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ISBN:
(纸本)9781424445233
Operation of the gun/turret system in a military tank is limited by several constraints some of which are posed by obstacles existing on the vehicle's own platform. These mechanical constraints acting as hard constraints can cause serious damage to the whole assembly if violated. A control strategy developed for such a system must avoid possible collision of the gun/turret system with these obstacles. We propose to use a MPC based control strategy, due to its inherent ability to handle constraints, for the deck clearance problem and evaluate its performance under operating conditions for a linear model of the tank. Matlab~R based MPCtoolbox is used to set up the MPC calculations for the gun/turret system. Simulations are performed to investigate and compare the performance of the controller under various deck constraint limits. It is shown that MPC is effective in addressing both the stabilization and deck clearance objectives.
In this paper, to further relax the restriction on the higher order nonlinearity in [7], a stable multiple model adaptive control (SMMAC) method is developed. First a new robust adaptive controller is designed, which ...
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ISBN:
(纸本)9781424445233
In this paper, to further relax the restriction on the higher order nonlinearity in [7], a stable multiple model adaptive control (SMMAC) method is developed. First a new robust adaptive controller is designed, which can guarantee the stability of the closed-loop system. Then to improve the system performance, the SMMAC method is presented by switching between the robust adaptive controller and a conventional neural network (NN) adaptive controller. Theory analysis and simulation results are presented to show the effectiveness of the proposed method.
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