A New QFT Design Methodology for Feedback Systems Under Input Saturation

1999 ◽  
Vol 123 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Wei Wu ◽  
Suhada Jayasuriya
Keyword(s):  
Robust Stability ◽  
Design Methodology ◽  
Design Method ◽  
Input Saturation ◽  
Function Technique ◽  
Feedback Systems ◽  
Robust Performance ◽  
Saturation Nonlinearity ◽  
Performance Requirements ◽  
And Performance

Presented in this paper is a design methodology for robust stability and robust performance for a large class of plants subject to an input saturation nonlinearity. Based on Horowitz’s 3-DOF linear design method, a more general form for the additional loop transmission around the saturating element is proposed to design the third degree of freedom Hs, for Type n plants, n⩾1. Robust stability is established with the circle criterion and the describing function technique, and robust performance is improved by imposing nonovershooting conditions. All stability and performance requirements are then transferred into frequency domain design bounds which are easily obtained using QFT design techniques. This procedure applies to all SISO, Type n, stable plants with uncertainties (parametric or nonparametric), and to marginally stable and conditionally stable plants as well.

Nonlinear Compensation for High Performance Feedback Systems With Actuator Imperfections

2013 ◽  
Author(s):  
Cameron L. Mock ◽  
Zachary T. Hamilton ◽  
Dustin Carruthers ◽  
John F. O’Brien
Keyword(s):  
Performance Feedback ◽  
High Performance ◽  
Vibration Suppression ◽  
Actuator Saturation ◽  
Design Method ◽  
Nonlinear Feedback ◽  
Feedback Systems ◽  
Performance Requirements ◽  
Common Causes ◽  
And Performance

Measures to reduce control performance for greater robustness (e.g. reduced bandwidth, shallow loop roll-off) must be enhanced if the plant or actuators are known to have nonlinear characteristics that cause variations in loop transmission. Common causes of these nonlinear behaviors are actuator saturation and friction/stiction in the moving parts of mechanical systems. Systems with these characteristics that also have stringent closed loop performance requirements present the control designer with an extremely challenging problem. A design method for these systems is presented that combines very aggressive Nyquist-stable linear control to provide large negative feedback with nonlinear feedback to compensate for the effects of multiple nonlinearities in the loop that threaten stability and performance. The efficacy of this approach is experimentally verified on a parallel kinematic mechanism with multiple uncertain nonlinearities used for vibration suppression.

Modelling and robust attitude trajectory tracking control of 3-DOF four rotor hover vehicle

2017 ◽  
Vol 89 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Rooh ul Amin ◽  
Aijun Li
Keyword(s):  
Robust Stability ◽  
Trajectory Tracking ◽  
Attitude Control ◽  
Tracking Control ◽  
Robust Performance ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Content Type ◽  
Uncertainty Model ◽  
And Performance

Purpose The purpose of this paper is to present μ-synthesis-based robust attitude trajectory tracking control of three degree-of-freedom four rotor hover vehicle. Design/methodology/approach Comprehensive modelling of hover vehicle is presented, followed by development of uncertainty model. A μ-synthesis-based controller is designed using the DK iteration method that not only handles structured and unstructured uncertainties effectively but also guarantees robust performance. The performance of the proposed controller is evaluated through simulations, and the controller is also implemented on experimental platform. Simulation and experimental results validate that μ-synthesis-based robust controller is found effective in: solving robust attitude trajectory tracking problem of multirotor vehicle systems, handling parameter variations and dealing with external disturbances. Findings Performance analysis of the proposed controller guarantees robust stability and also ensures robust trajectory tracking performance for nominal system and for 15-20 per cent variations in the system parameters. In addition, the results also ensure robust handling of wind gusts disturbances. Originality/value This research addresses the robust performance of hover vehicle’s attitude control subjected to uncertainties and external disturbances using μ-synthesis-based controller. This is the only method so far that guarantees robust stability and performance simultaneously.

scholarly journals Modelling and simulation for control of nutrient application in closed growing systems

1997 ◽  
Vol 45 (1) ◽  
pp. 127-142
Author(s):  
T.H. Gieling ◽  
J. Bontsema ◽  
T.W.B.M. Bouwmans ◽  
R.H. Steeghs
Keyword(s):  
Design Method ◽  
Model Description ◽  
Robust Performance ◽  
Robust Controller ◽  
Algorithm Performance ◽  
Design Procedures ◽  
Real Process ◽  
Standard Design ◽  
And Performance ◽  
Robust Design Method

The design of a controller for water supply and nutrient application in closed growing systems is presented and discussed with reference to nutrient film techniques in a 150 msuperscript 2 greenhouse. The 'robust design' method aims to distinguish between stability and performance and, in this case, the method deals with uncertainties in the model description of the real process, i.e. variability of flow and seasonal changes. Robust performance and robust stability, as qualities of the controlled process, were shown to be feasible for the control of nutrient application in closed growing systems. Algorithm performance was tested in a simulation procedure and shows very good disturbance suppression, staying well within the pre-set 10% limits. More standard design procedures could lead to a stable controlled process but would certainly be more conservative than the robust controller presented.

scholarly journals Fuzzy Adaptive DSC Design for an Extended Class of MIMO Pure-Feedback Non-Affine Nonlinear Systems in the Presence of Input Constraints

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Ning Wang ◽  
Ying Wang ◽  
Maolong Lv
Keyword(s):  
Dynamic System ◽  
Input Saturation ◽  
Dynamic Surface Control ◽  
Continuous Systems ◽  
Feedback Systems ◽  
Fuzzy Logic Systems ◽  
Dynamic Surface ◽  
Saturation Nonlinearity ◽  
Adaptive Parameters ◽  
Affine Functions

A novel adaptive fuzzy dynamic surface control (DSC) scheme is for the first time constructed for a larger class of (multi-input multi-output) MIMO non-affine pure-feedback systems in the presence of input saturation nonlinearity. First of all, the restrictive differentiability assumption on non-affine functions has been canceled after using the piecewise functions to reconstruct the model for non-affine nonlinear functions. Then, a novel auxiliary system with bounded compensation term is firstly introduced to deal with input saturation, and the dynamic system employed in this work designs a bounded compensation term of tangent function. Thus, we successfully relax the strictly bounded assumption of the dynamic system. Additionally, the fuzzy logic systems (FLSs) are used to approximate unknown continuous systems functions, and the minimal learning parameter (MLP) technique is exploited to simplify control design and reduce the number of adaptive parameters. Finally, two simulation examples with input saturation are given to validate the effectiveness of the developed method.

Robust multivariable controller design methodology: stability and performance requirements

1991 ◽  
Vol 46 (5-6) ◽  
pp. 1299-1310 ◽  
Author(s):  
J.L. Figueroa ◽  
O.E. Agamennoni ◽  
A.C. Desages ◽  
J.A. Romagnoli
Keyword(s):  
Design Methodology ◽  
Controller Design ◽  
Performance Requirements ◽  
Multivariable Controller ◽  
And Performance

scholarly journals DESIGN CONCEPT FOR GREEN PUBLIC SPACE IN KAMPONG

2015 ◽  
Vol 39 (2) ◽  
pp. 116-123 ◽  
Author(s):  
Sukmo D. Widharto ◽  
Nurfahmi Muchlis ◽  
Sigit H. Laksono ◽  
Purwanita Setijanti
Keyword(s):  
Public Space ◽  
Adaptive Design ◽  
Design Method ◽  
Limited Range ◽  
Design Concept ◽  
The Public ◽  
Performance Requirements ◽  
The People ◽  
Diverse Society ◽  
And Performance

The lack of environmentally friendly development in major city has made the public space in kampongs (or kampung) neglected. The need of a green community space to interact is increasingly scarce. The remaining areas that can be used as an outdoor space are alleys and pathways inside kampong. Public space should then be adaptive in order to meet the demands in a diverse society, thus emerged a design concept of adaptive public space using the capabilities of bamboo to deliver adaptive spaces with a limited range of conditions in its design, construction and usability. Bamboo has been frequently used by the people because of its sustainable characteristic. The method used in this study is the case study method. Qualitative data were collected through observations and interviews resulted in the analysis of existing conditions then formulized as a design criteria. Design method uses the concept of programming which is to formulate the mission, goals and performance requirements to create a concept. The drawn conclusion is that the alleys inside the kampong can be used as a public space by applying adaptive design principles. The use of bamboo in design is an appropriate solution based on its construction and material properties.

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