Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.|Control Systems Centre, Department of Electrical Engineering and Electronics, P.O. Box 88, UMIST, Manchester M60 1QD, UK.