A multi-model control of nonlinear systems: A cascade decoupled design procedure based on stability and performance

2019 ◽  
Vol 42 (7) ◽  
pp. 1271-1280 ◽  
Author(s):  
Mahdi Ahmadi ◽  
Pouya Rikhtehgar ◽  
Mohammad Haeri
Keyword(s):  
Design Procedure ◽  
Performance Criteria ◽  
Gap Metric ◽  
Redundancy Problem ◽  
Model Control ◽  
Cascade Structure ◽  
Independent Cascade ◽  
And Performance ◽  
Model Redundancy ◽  
The Stability

Recently, the multi-model controllers design was proposed in the literature based on integrating of the stability and performance criteria. Although these methods overcome the redundancy problem, the decomposition step is very complex and time consuming. In this paper, a cascade design of multi-model control is presented that is made from two sequential steps. In the first step, the nonlinear system is decomposed into a set of linear subsystems by just considering the stability criterion. In this step, the gap metric is used as a smart tool to measure the distance between linear subsystems. While the closed-loop stability is gained through the first step, the performance is improved in the second step by adding internal model controllers in a cascade structure. Therefore, the proposed idea supports designing a multi-model controller in a simple way by integrating the stability and performance criteria in two independent cascade steps. As a result, the proposed method avoids the model redundancy problem, has a simple structure, guarantees the robust stability, and improves the performance. Two nonlinear chemical processes are simulated to evaluate the proposed multi-model controller approach.

Stability and Performance of Virtual Reality-Based Telenanomanipulation System in SEM

2011 ◽  
Vol 183-185 ◽  
pp. 1746-1751 ◽  
Author(s):  
Dong Jie Li ◽  
Wei Bin Rong ◽  
Li Ning Sun ◽  
Wan Zhe Xiao
Keyword(s):  
Force Feedback ◽  
Design Procedure ◽  
Haptic Interface ◽  
Human Contact ◽  
Virtual Coupling ◽  
And Performance ◽  
The Stability ◽  
Carbon Nanowires ◽  
Measuring Force ◽  
Scanning Electron

In this paper, a master/slave telenanomanipulation control system with force feedback is established with the micro-positioner (Attocube) working in scanning electron microscope (SEM) as the slave side and the haptic device (Omega3) as the master side. An improved virtual coupling (IVC) algorithm is introduced based on nanoscale virtual coupling (NSVC) by adding a proportional- plus-integral (PI) velocity controller in the haptic interface. The stability and performance of the established system are discussed. This method leads to an explicit design procedure for virtual coupling networks which give greatest performance while guaranteeing stability both on moving carbon nanowires in SEM and measuring force at the point of device-human contact.

scholarly journals Research on Face Recognition Method by Autoassociative Memory Based on RNNs

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qi Han ◽  
Zhengyang Wu ◽  
Shiqin Deng ◽  
Ziqiang Qiao ◽  
Junjian Huang ◽  
...  
Keyword(s):  
Face Recognition ◽  
Design Procedure ◽  
Biological Database ◽  
Model Parameters ◽  
Face Database ◽  
Recognition Method ◽  
The Face ◽  
Model Training ◽  
And Performance ◽  
The Stability

In order to avoid the risk of the biological database being attacked and tampered by hackers, an Autoassociative Memory (AAM) model is proposed in this paper. The model is based on the recurrent neural networks (RNNs) for face recognition, under the condition that the face database is replaced by its model parameters. The stability of the model is proved and analyzed to slack the constraints of AAM model parameters. Besides, a design procedure about solving AAM model parameters is given, and the face recognition method by AAM model is established, which includes image preprocessing, AAM model training, and image recognition. Finally, simulation results on two experiments show the feasibility and performance of the proposed face recognition method.

scholarly journals Stability and Performance Analysis of Electrodynamic Thrust Bearings

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 11 ◽  
Author(s):  
Joachim Van Verdeghem ◽  
Virginie Kluyskens ◽  
Bruno Dehez
Keyword(s):  
Performance Criteria ◽  
Axial Stiffness ◽  
Minimal Amount ◽  
Dynamical Models ◽  
Thrust Bearings ◽  
Detent Force ◽  
Linear State ◽  
And Performance ◽  
The Stability

Electrodynamic thrust bearings (EDTBs) provide contactless rotor axial suspension through electromagnetic forces solely leaning on passive phenomena. Lately, linear state-space equations representing their quasi-static and dynamic behaviours have been developed and validated experimentally. However, to date, the exploitation of these models has been restricted to basic investigations regarding the stiffness and the rotational losses as well as qualitative stability analyses, thus not allowing us to objectively compare the intrinsic qualities of EDTBs. In this context, the present paper introduces four performance criteria directly related to the axial stiffness, the bearing energy efficiency and the minimal amount of external damping required to stabilise the thrust bearing. In addition, the stability is thoroughly examined via analytical developments based on these dynamical models. This notably leads to static and dynamic conditions that ensure the stability at a specific rotor spin speed. The resulting stable speed ranges are studied and their dependence to the axial external stiffness as well as the external non-rotating damping are analysed. Finally, a case study comparing three topologies through these performance criteria underlines that back irons fixed to the windings are not advantageous due to the significant detent force.

Multimodel Control of Nonlinear Systems: An Improved Gap Metric and Stability Margin-Based Method

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Mahdi Ahmadi ◽  
Mohammad Haeri
Keyword(s):  
Nonlinear Systems ◽  
Controller Design ◽  
A Priori ◽  
Stability Margin ◽  
Threshold Value ◽  
Performance Criteria ◽  
Local Models ◽  
Gap Metric ◽  
Maximum Stability ◽  
And Performance

This paper presents a new multimodel controller design approach incorporating stability and performance criteria. The gap metric is employed to measure the distance between local models. An efficient method based on state feedback strategy is introduced to improve the maximum stability margin of the local models. The proposed method avoids local model redundancy, simplifies the multimodel controller structure, and supports employing of many linear control techniques, while does not rely on a priori experience to choose the gridding threshold value. To evaluate the proposed method, three benchmark nonlinear systems are studied. Simulation results demonstrate that the method provides the closed-loop stability and performance via a simple multimodel structure in comparison with the opponents.

A New Structured Multimodel Control of Nonlinear Systems by Integrating Stability Margin and Performance

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Mahdi Ahmadi ◽  
Mohammad Haeri
Keyword(s):  
Nonlinear Systems ◽  
Controller Design ◽  
A Priori ◽  
Design Procedure ◽  
Stability Margin ◽  
Point Tracking ◽  
Performance Requirements ◽  
Performance Specifications ◽  
And Performance ◽  
Model Redundancy

This paper deals with a new systematic multimodel controller design for nonlinear systems. The design of local controllers based on performance requirements is incorporated with the concept of local models selection as an optimization problem. Gap metric and stability margin are used as measuring tool and operation space dividing criterion, respectively. The developed method provides support to design a simple structured multiple proportional-integral (PI) controller which guarantees both robust stability and time-domain performance specifications. The main advantages of the proposed method are avoiding model redundancy, not needing a priori knowledge about system, having simple structure, and easing the implementation. To evaluate the presented multimodel controller design procedure, three benchmark nonlinear systems are studied. Both simulations and experimental results prove the effectiveness of the proposed method in set point tracking and disturbance rejection.

Tracking Control of Robot Manipulator Using Sliding Mode Controller With Performance Robustness

1999 ◽  
Vol 121 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Chieh-Li Chen ◽  
Rui-Lin Xu
Keyword(s):  
Tracking Control ◽  
Feedback Linearization ◽  
Controller Design ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Design Procedure ◽  
Sliding Mode Controller ◽  
Systematic Design ◽  
And Performance ◽  
The Stability

The tracking control problem of robot manipulator is considered in this paper. A sliding mode controller design with global invariance is proposed using the concept of extended system and feedback linearization. The sliding surface is assigned such that the sliding mode motion will occur while the proposed control law is applied. This results in a system with global invariance. The stability and performance of the resulting system can be guaranteed by the proposed systematic design procedure.

An Internal Model Control Anti-Windup Scheme With Improved Performance for Input Saturation Via Loop Shaping

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Wei Wu ◽  
Suhada Jayasuriya
Keyword(s):  
Internal Model ◽  
Input Saturation ◽  
Internal Model Control ◽  
Constrained System ◽  
Stability Robustness ◽  
Loop Shaping ◽  
Model Control ◽  
Improved Performance ◽  
And Performance ◽  
The Stability

Proposed here is a new approach for synthesizing an internal model control (IMC) anti-windup (AW) compensator for a stable plant subject to input saturation. Built on the conventional IMC AW scheme, which preserves the stability robustness of the unconstrained system, the proposed linear AW compensator improves the performance of the constrained system. The analysis conducted through the loop decomposition of the AW system clearly reveals the impacts of the AW compensator on the closed-loop stability and performance. Loop shaping techniques are executed to design the AW compensator. The effectiveness of this approach is demonstrated using a numerical example.

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