The discretization of the analog Smith predictor by using the prediction-based state-matching digital redesign method for systems with various input time delays was recently investigated in the literature. This paper presents an alternative Chebyshev quadrature state-matching digital redesign method for discretization of the analog Smith predictor for systems with a long input time delay. In order to implement the digitally redesigned Smith predictor by utilizing the output-feedback of the plant, an ideal state reconstructor for the long input-delayed plant is established. The long dead time of interest is an integer plus a fractional input delay. An illustrative example is given to demonstrate the effective of the proposed approach.

This paper presents a newly developed digital redesign control scheme with a weighted switching strategy and output-reference tracking, for a cascaded analog system with state saturation and external loads. The proposed method improves the generally poor transition response and output deviation caused by state-saturation constraint and external loads. It replaces an existing or theoretically well-designed analog controller with state saturation, by a digital controller with almost identical performance.

In this paper, we propose a new dual-rate, observer-based control scheme utilizing digital redesign and a weighted switching strategy for cascaded systems with saturating actuators and state constraints. The weighted switching approach, which uses an evolutionary programming optimal search technique, improves the generally poor transition response caused by nonlinear constraints on saturating actuators and state constraints. An inner loop state compensator is provided to correct the windup effects on the actuator. The designed scheme can easily be implemented using digital processors and enables us to improve the performance of cascaded systems with saturating actuators and state constraints. An illustrative example is presented to demonstrate the effectiveness of the proposed methodology.

A technique is described that allows the staining and subsequent visualization of polymers that contain the phosphorylcholine (PC) group. These materials are useful as bulk materials or coatings for the fabrication of medical devices. The staining method employs rhodamine 6G, which can be simply and rapidly applied to the polymer coating and imaged using fluorescence microscopy. The specificity of the staining for the PC polymers makes this technique suitable for the evaluation of a wide range of substrates and provides qualitative information on coating uniformity, coverage and morphology. It can be used to examine the durability of, and defects in, the coating. Statistical analysis of the fluorescent intensity by measuring the pixel value during imaging can allow for the method to be used as a quality control tool.

A linear-quadratic-regulator-based design methodology is proposed to design proportional-integral-derivative (PID) controllers for multivariable systems with load disturbances. Except for a few parameters that are preliminarily selected, most of the PID parameters are systematically tuned using the developed plant state-feedback and controller state-feedforward LQR approach, such that satisfactory performance with guaranteed closed-loop stability is achieved. In order to access the plant state variables and carry out disturbance rejection, an observer-based disturbance rejection technique is proposed, which through an 'equivalent disturbance' concept, retains the observation error to be used for disturbance compensation. This makes disturbance measurement unnecessary and the disturbance rejection tuning independent of the set-point response adjustment. A robust stability analysis is also included for the modelling error. An illustrative example is given for comparison with alternative techniques.

Water and Environment JournalVolume 2, Issue 4 p. 365-375 Water Management in a Rural Area: Present and Future J. A. HUDSON PhD, MSc, J. A. HUDSON PhD, MSc Member Search for more papers by this authorA. C. DUNN BSc, CEng, DMS, MICE, A. C. DUNN BSc, CEng, DMS, MICE Member Search for more papers by this authorR. I. LLOYD BSc, CEng, MIMechE, R. I. LLOYD BSc, CEng, MIMechE Member Search for more papers by this author J. A. HUDSON PhD, MSc, J. A. HUDSON PhD, MSc Member Search for more papers by this authorA. C. DUNN BSc, CEng, DMS, MICE, A. C. DUNN BSc, CEng, DMS, MICE Member Search for more papers by this authorR. I. LLOYD BSc, CEng, MIMechE, R. I. LLOYD BSc, CEng, MIMechE Member Search for more papers by this author First published: August 1988 https://doi.org/10.1111/j.1747-6593.1988.tb01308.xAboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume2, Issue4August 1988Pages 365-375 RelatedInformation