Design of a Nonlinear Adaptive Controller for an Electrohydraulic Actuator1

1998 ◽  
Vol 123 (3) ◽  
pp. 449-456 ◽  
Author(s):  
K. Ziaei ◽  
N. Sepehri
Keyword(s):  
Low Cost ◽  
Dead Zone ◽  
Flow Characteristics ◽  
Adaptive Controller ◽  
Recursive Least Squares ◽  
Plant Model ◽  
Low Performance ◽  
Improved Performance ◽  
And Performance ◽  
Model Reference Adaptive

This paper presents a new implementation of indirect model reference adaptive (MRA) control scheme for positioning of hydraulic actuators that operate by low-cost proportional valves. A proper linear discrete-time plant model is used which has dead-time and no zeros, eliminating the possibility of unstable pole-zero cancellation. The robustness of the parameter adaptation is achieved by employing the recursive least-squares algorithm in combination with a dead-zone in the adaptive law. It is shown that while the controller is adequate for hydraulic valves with linear flow characteristics, it exhibits low performance in the presence of deadband and nonlinear orifice opening characteristics of low-cost proportional valves. The linear plant model is therefore augmented by adding a static nonlinearity. The resulting nonlinear MRA controller is shown to have improved performance over its linear counterpart. Step-by-step experiments are presented to confirm the effectiveness and performance improvement of the proposed method.

Subsonic Propulsion System Installation Analysis and Optimization

1991 ◽  
Author(s):  
J. L. Colehour ◽  
B. W. Farquhar ◽  
J. E. Gengler ◽  
T. A. Reyhner
Keyword(s):  
Potential Flow ◽  
Low Cost ◽  
Flow Analysis ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Inviscid Flow ◽  
Wave Drag ◽  
Propulsion System ◽  
Design Development ◽  
Improved Performance

Computational fluid dynamics (CFD) now allows analysis of propulsion system installations on subsonic transports to an extent that many configuration decisions can be made without testing. The methods discussed here utilize low-cost potential flow methods to predict inviscid flow characteristics and utility methods to model geometry, generate computational mesh, estimate wave drag, and perturb geometry in ways that promise improved performance. Jet plume effects are included in the potential flow analysis by means of a plume simulation method. Wave drag predictions yield levels of drag that are consistent with wind tunnel results, and, through contour optimization, wave drag for a trial propulsion installation geometry was reduced by about 50%. We conclude that through the use of methods such as these, many propulsion system installation design decisions can be made by analysis relatively quickly, which should lead to reduced design development time and cost.

Backstepping-based model reference adaptive controller for a multi-axial system in the presence of external disturbance and saturated input

2017 ◽  
Vol 40 (3) ◽  
pp. 776-784 ◽  
Author(s):  
Van Tu Duong ◽  
Huy Hung Nguyen ◽  
Jae Hoon Jeong ◽  
Hak Kyeong Kim ◽  
Sang Bong Kim
Keyword(s):  
Control Method ◽  
Dead Zone ◽  
External Disturbance ◽  
Adaptive Controller ◽  
Auxiliary System ◽  
Design Stage ◽  
Recursive Structure ◽  
Model Reference ◽  
Model Reference Adaptive ◽  
Axial System

This paper presents a backstepping-based model reference adaptive controller for a multi-axial system in the presence of external disturbance and saturated input. The proposed controller synthesizes the backstepping technique and the model reference adaptive control method to construct control inputs for recursive structure and uncertain modelling of the multi-axial system. To cope with the limit of saturated input, an auxiliary system is adopted. A dead-zone modification is introduced to avoid the drift phenomenon of adjusted adaptive parameters. The stability of the proposed controller is proven by Lyapunov’s theory while considering the effect of the auxiliary system and the dead-zone modification in the design stage. The effectiveness and performance of the proposed controller are evaluated by experiment on a transformer winding system.

A Robot System for the Control of Fabric Tension for Inspection

2007 ◽  
Author(s):  
E. H. K. Fung ◽  
C. W. M. Yuen ◽  
L. C. Hau ◽  
W. K. Wong ◽  
L. K. Chan
Keyword(s):  
Force Feedback ◽  
Reaction Force ◽  
Adaptive Controller ◽  
Stepper Motor ◽  
Robot System ◽  
Customer Expectation ◽  
Model Reference Adaptive System ◽  
Inspection Process ◽  
And Performance ◽  
Model Reference Adaptive

This paper describes the performance of a stepper-motor-based robot system that exerts a prescribe tension on fabrics to facilitate inspection process. In fact, inspection is an important part of quality control in the textile and clothing industry. It is a useful tool to safeguard the quality and ensure that the product can meet the customer expectation and the relevant stipulated standard. Obviously, before the automated inspection process, it is necessary to expand the fabrics being tested to have certain tension. Due to the nonlinear nature of fabric stiffness, it is essential that an adaptive force feedback control be employed to regulate the applied tension. A pair of symmetrical two-link mechanisms with a revolute joint, driven by a stepper motor, in conjunction with an adaptive controller, constitutes the robot system proposed in the present work. The two mechanisms are responsible for stretching the fabrics to be inspected, while the controller regulates the stretching force to the desired value by sensing the reaction force exerted on the links by the fabrics. In order to update the controller parameters so as to account for the nonlinear change of the fabric stiffness, a Model-Reference Adaptive System (MRAS) based on the augmented error is designed. The performance of MRAS is compared with a Proportional-plus-Integral (PI) control. A short-sleeved T-shirt made of knitted fabric is considered for the demonstration of the system. Besides, a prescribed value of tension is set to the system. Numerical simulations are conducted to illustrate the feasibility and performance of the proposed system. Successful outcomes of the present work establish a foundation for the real implementation of the hanger.

Aero Engine Development for the Future

1983 ◽  
Vol 197 (3) ◽  
pp. 149-157 ◽  
Author(s):  
H W Bennett
Keyword(s):  
Mechanical Design ◽  
Low Cost ◽  
Fuel Efficiency ◽  
Thermodynamic Cycle ◽  
Aircraft Engine ◽  
Advanced Technology ◽  
High Fuel Efficiency ◽  
Aero Engine ◽  
Improved Performance ◽  
And Performance

A historical survey of the development and future trends in aero engine design and performance are given. Emphasis is placed on the achievement of low cost of ownership through high fuel efficiency. Simple basic principles controlling the conceptual design and performance are described. The choice of engine thermodynamic cycle is discussed with emphasis on the civil transport engine. The differing requirements of the military aircraft engine are briefly stated. Short-term possibilities for improved performance and longer term speculative proposals are made. Advanced technology requirements in materials, mechanical design and aerodynamics are outlined.

Performance of lamella clarifiers for juice and syrup clarification

2017 ◽  
pp. 144-150
Author(s):  
Peter W. Rein ◽  
M. Getaz ◽  
A. Raghunandan ◽  
N. du Pleissis ◽  
H. Saleh ◽  
...  
Keyword(s):  
Residence Time ◽  
Flow Characteristics ◽  
Preliminary Test ◽  
Practical Experience ◽  
Operating Costs ◽  
Capital Costs ◽  
Computational Fluid Dynamics Cfd ◽  
Improved Performance ◽  
Work Done ◽  
Good Flow

A new design for syrup and juice clarifiers is presented. The design takes advantage of the considerably improved performance of clarifiers incorporating lamella plates, and the reasons for the improvement are outlined. Computational fluid dynamics (CFD) work done to simulate the performance is summarised. This design enables the residence time to be dramatically reduced and the simplified design leads to cheaper and better clarifiers. Practical experience with factory scale units is described, confirming the good flow characteristics. The results of preliminary test work on a factory syrup clarifier are presented, which is also shown to operate efficiently as a phosphatation clarifier. In addition the performance of a full-scale juice clarifier has been evaluated and compared with the performance of a Rapidorr clarifier. This work confirms the considerable advantages which this type of design provides, in realising substantial reductions in residence time, capital costs and operating costs.

Programmable Integrated Photonics

2020 ◽  
Author(s):  
José Capmany ◽  
Daniel Pérez
Keyword(s):  
Integrated Circuit ◽  
Performance Monitoring ◽  
Low Cost ◽  
Limiting Factors ◽  
External Control ◽  
Integrated Photonics ◽  
New Paradigm ◽  
Photonic Integrated Circuit ◽  
And Performance ◽  
Application Fields

Programmable Integrated Photonics (PIP) is a new paradigm that aims at designing common integrated optical hardware configurations, which by suitable programming can implement a variety of functionalities that, in turn, can be exploited as basic operations in many application fields. Programmability enables by means of external control signals both chip reconfiguration for multifunction operation as well as chip stabilization against non-ideal operation due to fluctuations in environmental conditions and fabrication errors. Programming also allows activating parts of the chip, which are not essential for the implementation of a given functionality but can be of help in reducing noise levels through the diversion of undesired reflections. After some years where the Application Specific Photonic Integrated Circuit (ASPIC) paradigm has completely dominated the field of integrated optics, there is an increasing interest in PIP justified by the surge of a number of emerging applications that are and will be calling for true flexibility, reconfigurability as well as low-cost, compact and low-power consuming devices. This book aims to provide a comprehensive introduction to this emergent field covering aspects that range from the basic aspects of technologies and building photonic component blocks to the design alternatives and principles of complex programmable photonics circuits, their limiting factors, techniques for characterization and performance monitoring/control and their salient applications both in the classical as well as in the quantum information fields. The book concentrates and focuses mainly on the distinctive features of programmable photonics as compared to more traditional ASPIC approaches.

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