Cascade Control of Interconnected System Using Neural Network

Abstract

This paper deals with the application of neural networks in the cascade control of an interconnected system. In this scheme, the neural network has been used to develop the primary and secondary controllers. The performance and stability of the neural controller is affected by the selection of the network parameters. In this work an adaptive change of the learning rate and momentum factor is proposed. The performances of the controller for the set point tracking and the disturbance rejection show that an efficient neural control system can be realized by using adaptive learning rate and momentum factor. In order to improve the transient as well as steady state responses, a linear feedback compensator (LFBC) has been added in parallel with the primary and secondary control network. The feasibility of method has been tested on the example of simulated system. The control strategy further experimentally tested on a laboratory set-up of the continuously stirred tank (CST) process. The robustness of the proposed system has been confirmed with respect to its performance for the set point tracking and also under the influence of load disturbance imposed on the system. The performance of the various control strategy has been compared in terms of integral square error (ISE).

Indexing terms:

• Process control
• Cascade control
• Neural network
• PID

Additional information

Notes on contributors

S C Saxena

S C SAXENA obtained BE (Electrical) from Allahabad University in 1970 and ME Electrical (M & I) and I PhD from University of Roorkee in 1973 and 1977 respectively. He has published about 140 research papers at National & International levels; written 6 monographs and received 9 awards including Khosla Gold Medal and cash award. Dr Saxena is a fellow of IEI, Fellow of IETE, and Life Member of BMESI, NIQR, ISTE and ISCEE. He is Vice-President of Biomedical Engg Society of India, former Council Member of the IE (I); former Chairman Roorkee local centre of the IE (I), Vice President ISCEE, Member management committee of UP State Centre of the IE(I), Chairman ISTE chapter at Indian Institute of Technology Roorkee, Vice-chairman, NIQR Chapter at Roorkee, and Chairman, Consultants Committee of Roorkee School for the Deaf. He has been the Honorary Secretary of Roorkee local Centre of the IE(I) and worked on number of Expert Committees of AICTE, New Delhi and University Sector Institutions. His areas of specializations are Biomedical Engineering, Measurement & Instrumentation. He has experience of over 25 years of consultancy and testing. Dr Saxena is a trained Motivation Trainer by NIMID Bombay and NIESBUD; New Delhi.

Vinod Kumar

Vinod Kumar obtained his BSc (Elect Engineering) Hons Degree from Punjab University in 1973, ME (Measurement & Instrumentation) Hons and PhD Degree from University of Roorkee, Roorkee in 1975 and 1984 respectively. He joined the Electrical Engineering Department of University of Roorkee, Roorkee in 1975. He has published more than 90 research papers, guided 52 PG students; supervised 9 and supervising 4 PhD theses. He has undertaken large number of consultancy & sponsored projects from industries and government departments. He was elected as Fellow of Institution of Engineers (I), Institution of Electronics and Telecommunication Engineers, and is a member of many professional bodies. He has received many awards including Khosla Medal and best paper awards of the Institution of Engineers. He has organised a workshop on Biomedical Engineering Education to frame the model syllabi in the area of biomedical engineering.

L M Waghmare

L M Waghmare received BE and ME (Instrumentation) from SGGS College of Engineering and Technology, (Marathwada University, Aurangabad) Nanded in 1986 and 1990 respectively. He received PhD degree from Department of Electrical Engineering, Indian Institute of Technology, Roorkee in 2001. He has been with the Department of Instrumentation of SGGS College of Engineering and Technology, Nanded as a lecturer since 1986–1993 and currently he is an Assistant Professor. He has published one book and currently he is ISTE learning material on Transducers and Instrumentation. He has published 20 papers in the National/International journal/Conferences. His current research interests are in the area of neural networks and its applications, fuzzy logic, system identification, control and computer applications in process control.