Smith predictor with inverted decoupling for square multivariable time delay systems

Abstract

This paper presents a new methodology to design multivariable Smith predictor for n × n processes with multiple time delays based on the centralised inverted decoupling structure. The controller elements are calculated in order to achieve good reference tracking and decoupling response. Independent of the system size, very simple general expressions for the controller elements are obtained. The realisability conditions are provided and the particular case of processes with all of its elements as first-order plus time delay systems is discussed in more detail. A diagonal filter is added to the proposed control structure in order to improve the disturbance rejection without modifying the nominal set-point response and to obtain a stable output prediction in unstable plants. The effectiveness of the method is illustrated through different simulation examples in comparison with other works.

An Analytical Design of Simplified Decoupling Smith Predictors for Multivariable Processes

“…In this work, Smith predictors were adopted to overcome this issue, and as mentioned above, the delay terms were also eliminated from the closed loops. As a result, we could use various methods to design multi-loop controllers for multi-loop delay-free systems (18)(19)(20); that is, i θ could be removed from Equations (15)- (17) when designing the controllers:…”

“…where p A (s) contains delay time terms and/or right half plane (RHP)zeroes and p A (0) = 1. According to Equations (18)- (20), p A (s) = 1. Generally, the IMC controller is designed as…”

“…From this method, the DTC structure can handle integrating and unstable processes [16,17]. In addition, other scholars have also extended this scheme to MIMO cases as well [18][19][20][21][22][23].…”

“…The first one is an FSP structure which is applied directly to the whole multivariable system [18,19,21,22]. The second one is done in combination with decoupling techniques which simplify the transfer function matrix of processes and then address an SP scheme for each single loop like that of SISO systems [20]. In the present work, the latter was adopted by using the simplified decoupling technique and the original SP for the sake of simplicity.…”

Model Mediation to Overcome Light Limitations—Toward a Secure Tactile Internet System

“…In 1975, Otto J. M. Smith developed the first predictor algorithm, which is referred to as the smith predictor [66]. The smith predictor was developed for the linear time-invariant (LTI) feedback control system, to enhance the system stability.…”