An H∞ Synthesis of Robust Current Error Feedback Learning Control

1996 ◽  
Vol 118 (2) ◽  
pp. 341-346 ◽  
Author(s):  
C. J. Goh ◽  
W. Y. Yan
Keyword(s):  
Linear Time ◽  
Design Procedure ◽  
Learning Control ◽  
Open Loop ◽  
Control Law ◽  
Error Feedback ◽  
Feedback Systems ◽  
Unstable Systems ◽  
Feedback Learning ◽  
Current Error

Conventionally, iterative learning control law is updated using past error information. As a result, the controller is effectively open-loop, apart from being unable to control unstable systems, it also does not share the robustness properties of feedback systems. It is proposed that current error feedback should be used to update the learning control law instead. We present a systematic design procedure based on the H∞ control theory to construct a robust current error feedback learning control law for linear-time-invariant, and possibly unstable, systems. The optimal design will ensure: 1 That the closed-loop system is stable; 2 that the convergence rate is optimum about the nominal plant; 3 robustness in the presence of perturbed or unmodeled dynamics, or nonlinearity.

scholarly journals Open-closed Iterative Learning Control Algorithm for Exoskeleton Rehabilitation Purposes

2019 ◽  
Vol 292 ◽  
pp. 01010
Author(s):  
Mihailo Lazarević ◽  
Nikola Živković ◽  
Darko Radojević
Keyword(s):  
Iterative Learning Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Control Law ◽  
Exact Linearization ◽  
Outer Loop ◽  
Control Scheme

The paper designs an appropriate iterative learning control (ILC) algorithm based on the trajectory characteristics of upper exosk el eton robotic system. The procedure of mathematical modelling of an exoskeleton system for rehabilitation is given and synthesis of a control law with two loops. First (inner) loop represents exact linearization of a given system, and the second (outer) loop is synthesis of a iterative learning control law which consists of two loops, open and closed loop. In open loop ILC sgnPDD2 is applied, while in feedback classical PD control law is used. Finally, a simulation example is presented to illustrate the feasibility and effectiveness of the proposed advanced open-closed iterative learning control scheme.

Design and Convergence of a Time-Varying Iterative Learning Control Law

2004 ◽  
Author(s):  
Marina Tharayil ◽  
Andrew Alleyne
Keyword(s):  
Frequency Domain ◽  
Iterative Learning Control ◽  
Linear Time ◽  
Learning Control ◽  
Convergence Condition ◽  
Iterative Learning ◽  
Control Law ◽  
Equivalent Condition ◽  
Time Varying ◽  
Linear Time Invariant

This paper presents a novel linear time-varying (LTV) iterative learning control law that can provide additional performance while maintaining the robustness and convergence properties comparable to those obtained using traditional frequency domain design techniques. Design aspects of causal and non-causal linear time-invariant (LTI), along with the proposed LTV, ILC update laws are discussed and demonstrated using a simplified example. Asymptotic as well as monotonic convergence, robustness and performance characteristics of such systems are considered, and an equivalent condition to the frequency domain convergence condition is presented for the time-varying ILC. Lastly the ILC algorithm developed here is implemented on a Microscale Robotic Deposition system to provide experimental verification.

Robust output feedback learning control for induction motor servo drives

2008 ◽  
Vol 19 (15) ◽  
pp. 1745-1759 ◽  
Author(s):  
P. Tomei ◽  
C. M. Verrelli ◽  
M. Montanari ◽  
A. Tilli
Keyword(s):  
Induction Motor ◽  
Output Feedback ◽  
Learning Control ◽  
Feedback Learning ◽  
Servo Drives

scholarly journals Tuned Mass Damper Design for Slender Masonry Structures: A Framework for Linear and Nonlinear Analysis

2021 ◽  
Vol 11 (8) ◽  
pp. 3425
Author(s):  
Marco Zucca ◽  
Nicola Longarini ◽  
Marco Simoncelli ◽  
Aly Mousaad Aly
Keyword(s):  
Nonlinear Analysis ◽  
Linear Time ◽  
Design Procedure ◽  
Time History ◽  
Tuned Mass Damper ◽  
Second Phase ◽  
Masonry Structures ◽  
Base Shear ◽  
Mass Damper ◽  
Linear And Nonlinear

The paper presents a proposed framework to optimize the tuned mass damper (TMD) design, useful for seismic improvement of slender masonry structures. A historical masonry chimney located in northern Italy was considered to illustrate the proposed TMD design procedure and to evaluate the seismic performance of the system. The optimization process was subdivided into two fundamental phases. In the first phase, the main TMD parameters were defined starting from the dynamic behavior of the chimney by finite element modeling (FEM). A series of linear time-history analyses were carried out to point out the structural improvements in terms of top displacement, base shear, and bending moment. In the second phase, masonry's nonlinear behavior was considered, and a fiber model of the chimney was implemented. Pushover analyses were performed to obtain the capacity curve of the structure and to evaluate the performance of the TMD. The results of the linear and nonlinear analysis reveal the effectiveness of the proposed TMD design procedure for slender masonry structures.

scholarly journals Displacement-based design of precast hinged portal frames with additional dissipating devices at beam-to-column joints

2021 ◽  
Author(s):  
Andrea Belleri ◽  
Simone Labò
Keyword(s):  
Design Methodology ◽  
Linear Time ◽  
Design Procedure ◽  
Time History ◽  
Structural System ◽  
Additional Degree ◽  
Speed Up ◽  
Column Joint ◽  
Displacement Based ◽  
Mechanical Devices

AbstractThe seismic performance of precast portal frames typical of the industrial and commercial sector could be generally improved by providing additional mechanical devices at the beam-to-column joint. Such devices could provide an additional degree of fixity and energy dissipation in a joint generally characterized by a dry hinged connection, adopted to speed-up the construction phase. Another advantage of placing additional devices at the beam-to-column joint is the possibility to act as a fuse, concentrating the seismic damage on few sacrificial and replaceable elements. A procedure to design precast portal frames adopting additional devices is provided herein. The procedure moves from the Displacement-Based Design methodology proposed by M.J.N. Priestley, and it is applicable for both the design of new structures and the retrofit of existing ones. After the derivation of the required analytical formulations, the procedure is applied to select the additional devices for a new and an existing structural system. The validation through non-linear time history analyses allows to highlight the advantages and drawbacks of the considered devices and to prove the effectiveness of the proposed design procedure.

Iterative learning control algorithm for sensor fault nonlinear systems

2020 ◽  
pp. 1-8
Author(s):  
Zimian Lan
Keyword(s):  
Nonlinear Systems ◽  
Iterative Learning Control ◽  
Control Algorithm ◽  
Tracking Error ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Sensor Fault ◽  
Initial State ◽  
Control Gain

In this paper, we propose a new iterative learning control algorithm for sensor faults in nonlinear systems. The algorithm does not depend on the initial value of the system and is combined with the open-loop D-type iterative learning law. We design a period that shortens as the number of iterations increases. During this period, the controller corrects the state deviation, so that the system tracking error converges to the boundary unrelated to the initial state error, which is determined only by the system’s uncertainty and interference. Furthermore, based on the λ norm theory, the appropriate control gain is selected to suppress the tracking error caused by the sensor fault, and the uniform convergence of the control algorithm and the boundedness of the error are proved. The simulation results of the speed control of the injection molding machine system verify the effectiveness of the algorithm.

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