Discrete-Time Repetitive Control System Design Using the Regeneration Spectrum

1993 ◽  
Vol 115 (2A) ◽  
pp. 228-237 ◽  
Author(s):  
F.-R. Shaw ◽  
K. Srinivasan

The stability, transient response, and stability robustness of discrete-time repetitive control systems characterized by large values of the time delay inherent in such systems are examined here using a function of frequency termed the regeneration spectrum. The ability to infer different aspects of controlled system performance from the regeneration spectrum, and its ease of computation, makes it a valuable tool for controller analysis and synthesis. A design procedure for discrete-time repetitive control systems, based on the regeneration spectrum, is outlined and a controller form suggested to effectively handle the trade-off between the different aspects of controlled system behavior. The controller design procedure is applied to an electrohydraulic material testing application characterized by strong nonlinearities, and shown experimentally to be effective in improving the controlled system performance.

Author(s):  
A R Plummer ◽  
C S Ling

All practical control systems exhibit control signal saturation. The effect that this saturation has on the control system performance, especially stability and robustness, can be significant and must be understood at the controller design stage. This paper presents conditions for global asymptotic stability and measures of stability robustness for such systems. These are demonstrated through simulation examples, and it is shown how an understanding of the stability conditions can inform the controller design process. The off-axis circle criterion is used as the basis for a sufficient condition for stability, and it is argued that this is not overly restrictive in practice. The derivations are carried out in discrete time, and servo-system control is envisaged as an important application area for the techniques; however, the results are applicable more widely.


2020 ◽  
Vol 10 (20) ◽  
pp. 7260
Author(s):  
Amirhossein Ahmadi ◽  
Behnam Mohammadi-Ivatloo ◽  
Amjad Anvari-Moghaddam ◽  
Mousa Marzband

This paper investigates the linear quadratic integral (LQI)-based control of Z-source inverters in the presence of uncertainties such as parameter perturbation, unmodeled dynamics, and load disturbances. These uncertainties, which are naturally available in any power system, have a profound impact on the performance of power inverters and may lead to a performance degradation or even an instability of the system. A novel robust LQI-based design procedure is presented to preserve the performance of the inverter against uncertainties while a proper level of disturbance rejection is satisfied. The stability robustness of the system is also studied on the basis of the maximum sensitivity specification. Moreover, the bat algorithm is adopted to optimize the weighting matrices. Simulation results confirm the effectiveness of the proposed controller in terms of performance and robustness.


1990 ◽  
Vol 112 (3) ◽  
pp. 320-324 ◽  
Author(s):  
C. C. H. Ma

It is shown that a special zero phase control (ZPC) system introduced by Tomizuka is L∞ stable against a large class of common nonlinearities. However, it still suffers from the generic nonrobustness problem associated with a linear repetitive control system when subjected to a saturation nonlinearity. For the special ZPC system, however, three solutions exist for the problem, two of which do not degrade the repetitive tracking performance.


Author(s):  
D. Griffin ◽  
A. G. Kelkar

This paper presents a robust controller design for an automatic flight control system (AFCS) for a fighter aircraft model with eight inputs and seven outputs. The controller is designed based on McFarlane-Glover robustifying technique using a simple baseline LQG design. Controllers designed purely based on traditional LQG techniques are known to have no guaranteed robustness margins. The McFarlane-Glover technique can be used to enhance the stability robustness of the baseline LQG design using a two-step design process. In the first step, an LQG controller is designed which is optimized only for performance without any consideration to robustness. In the second step, the performance optimized LQG design is rendered robust using McFarlane-Glover procedure. The robustifying procedure uses a coprime factor uncertainty model and H∞ optimization. An important advantage of this procedure is that no problem dependent uncertainty modelling or weight selection is required in the second step of the process. The robustifying procedure also yields the quantitative estimate of the robustness.


Author(s):  
Zhong-Hua Pang ◽  
◽  
Guo-Ping Liu ◽  
Donghua Zhou ◽  
◽  
...  

This paper is concerned with the step output tracking controller design problem for networked discretetime linear systems. The communication constraints such as network-induced delay, packet disorder, and packet dropout are considered, which are treated as the round-trip time (RTT) delay with an upper bound. An event-driven networked predictive control scheme is proposed to actively compensate for the RTT delay, which avoids the requirement of synchronization between the controller side and the plant side. The stability of the closed-loop system and the design procedure of the observer-based controller are discussed. A numerical example is employed to illustrate the effectiveness of the proposed methods.


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