摘要:

Artificial neural networks are made up of highly interconnected layers of simple ‘neuron-like’ nodes. The neurons act as nonlinear processing elements within the network. An attractive property of artificial neural networks is that, given the appropriate network topology, they are capable of characterising nonlinear functional relationships. Furthermore, the structure of the resulting neural network based process model may be considered generic, in the sense that little prior process knowledge is required in its determination. The methodology therefore provides a cost efficient and reliable process modelling technique. The concepts involved in the formulation of artificial neural networks are introduced. Their suitability for solving some process engineering problems is discussed and illustrated using results obtained from both simulation studies and recent applications to industrial process data. In the latter, neural network models were used to provide estimates of biomass concentration in industrial fermentation systems and of top product composition of an industrial distillation tower. Measurements from established instruments such as off-gas carbon dioxide in the fermenter and overheads temperature in the distillation column were used as the secondary variables for the respective processes. The advantage of using these estimates for feedback control is demonstrated. The possibility of using neural network models directly in model based control strategies is also considered. The range of applications is an indication of the utility of artificial neural network methodologies within a process engineering environment.

DOI:10.1049/ip-d.1991.0036

出版商:IEE    

年代:1991

数据来源: IET

摘要:

In the paper, a method for the optimal (according to the quadratic performance index) control of a positioning drive with a permanentmagnet synchronous motor (PMSM) is developed. The proposed control method eliminates or reduces the influence of disturbances on the dynamics of the system. It is shown that the suggested methods are useful not only in the case of a linear system but also in a system with current and speed limitations. For this case, the control method is examined through computer simulation, and then tested in a real microprocessor-controlled drive system consisting of a permanently excited synchronous motor. The motor is fed by a transistor inverter with sinusoidal output currents. The results of this research show the utility of this method. In addition, an exact correlation between the theoretical and experimental results is shown.

DOI:10.1049/ip-d.1991.0037

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The use of self-organising fuzzy logic control for automated drug delivery in muscle relaxant anaesthesia is described. The self-elicitation of a knowledge base is shown to be robust in the presence of model uncertainty, noise contamination, and parameter changes. Being computing intensive, self-organising fuzzy logic control is considered for parallel implementation on transputers, both through use of a LISP interpreter and through direct OCCAM coding. The OCCAM code gave a fast implementation, which could be further improved by using multiple transputers.

DOI:10.1049/ip-d.1991.0038

出版商:IEE    

年代:1991

数据来源: IET

摘要:

This paper presents a method for finding the boundaries of constant gain margin and phase margin of sampled-data control systems. The considered systems are first modified by adding a gain-phase margin tester, then the characteristic equations are formulated and factored into stability equations, and finally the parameter-plane method is used to find the boundaries of constant gain margin and phase margin. The main advantage of the presented method is to obtain complete information about the effects of adjustable and/or variable parameters on gain margins and phase margins.

DOI:10.1049/ip-d.1991.0039

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A method for multiple fault diagnosis of plants described by a linear difference model is proposed in the form of an algorithm. The algorithm is based on the observation that, when the number of faulty units of the system is known, the set of faulty units can be differentiated from other sets by checking linear varieties in the measurement data space. It is further shown that the system withtnumber of faults can be diagnosed within (t+1) sample/time units if the input-output measurements are rich and that the algorithm can be used for diagnosis even when the number of faults is not known in advance.

DOI:10.1049/ip-d.1991.0040

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A recursive algorithm for the automatic tuning of PID regulators is described. The tuning strategy is based on the minimisation of a performance index which considers the quadratic deviations of the predicted output, over the set point, as well as the control efforts, over a time horizon. The adaptive version of this algorithm follows an explicit scheme so that the applications are not limited to self-tuning in the commissioning phase. It can also be applied to parameter adaptive control. The method has been successfully tested and some results are presented.

DOI:10.1049/ip-d.1991.0041

出版商:IEE    

年代:1991

数据来源: IET