Vibration Control of Single Link Flexible Manipulator by Using Neural Network


Book Description

This project presents simulation on minimizing vibration error in single link flexible manipulator system by using neural network system. Flexible manipulator system has a flexible link, an actuator-gear mechanism to rotate the link, an optical encoder to measure joint rotation, accelerometers and strain gauges to sense flexible motion, an optical arrangement to measure the endpoint position and an occasional force sensor attached to the end-point. The overall aim of this project is to develop a dynamic modeling and controller for single link flexible manipulator. In spite of it, we need to minimize the vibration using neural network controller in single link flexible manipulator. The vibration error that occurs in the flexible manipulator is needed to be study and try to reduce it by using the controller (neural network). Towards this thesis, the single link flexible manipulator system being minimize the error by using intelligent neural network controller, and be compared with system existing controller (PID) and the system without controller so that we can see the clearly error percentage reduced. In order to achieve the objective for this project, mathematical model will develop based on system identification using different method such as Lagrage method, Euler-Beurnoulli and System Identification Toolbox in MATLAB and implement it in Mathlab simulink. The results that we achieved is the neural network give the best in order to minimize the vibration error compared to the system without controller about 60% reduction of error and 10% of reduction of error when compared with system with PID controller. Conclusively, the intelligent neural network give us the better results and followed the characteristic of single link flexible manipulator as we desired.




Control of Flexible-link Manipulators Using Neural Networks


Book Description

Control of Flexible-link Manipulators Using Neural Networks addresses the difficulties that arise in controlling the end-point of a manipulator that has a significant amount of structural flexibility in its links. The non-minimum phase characteristic, coupling effects, nonlinearities, parameter variations and unmodeled dynamics in such a manipulator all contribute to these difficulties. Control strategies that ignore these uncertainties and nonlinearities generally fail to provide satisfactory closed-loop performance. This monograph develops and experimentally evaluates several intelligent (neural network based) control techniques to address the problem of controlling the end-point of flexible-link manipulators in the presence of all the aforementioned difficulties. To highlight the main issues, a very flexible-link manipulator whose hub exhibits a considerable amount of friction is considered for the experimental work. Four different neural network schemes are proposed and implemented on the experimental test-bed. The neural networks are trained and employed as online controllers.




A Neural Network-based Controller for a Single-link Flexible Manipulator Using the Inverse Dynamics Approach


Book Description

This thesis presents an intelligent strategy for controlling the tip position of a flexible-link manipulator. Motivated by the well-known inverse dynamics control approach for rigid-link manipulators, two multi-layer feedforward neural networks are developed to learn the nonlinearities of the system dynamics. The re-defined output scheme is used by feeding back this output to guarantee the minimum phase behavior of the resulting closed-loop system. No a priori knowledge about the nonlinearities of the system is needed where the payload mass is also assumed to be unknown. The weights of the networks are adjusted using a modified on-line error backpropagation algorithm that is based on the propagation of the redefined output error, derivative of this error and the tip deflection of the manipulator. Numerical simulations as well as real-time controller implementation on an experimental setup are carried out. The results achieved by the proposed neural network-based controller are compared in simulations and experimentally with conventional PD-type and inverse dynamics controls to substantiate and demonstrate the advantages and the promising potentials of this scheme.




Dynamic Modeling and Neural Network-Based Intelligent Control of Flexible Systems


Book Description

Comprehensive treatment of several representative flexible systems, ranging from dynamic modeling and intelligent control design through to stability analysis Fully illustrated throughout, Dynamic Modeling and Neural Network-Based Intelligent Control of Flexible Systems proposes high-efficiency modeling methods and novel intelligent control strategies for several representative flexible systems developed by means of neural networks. It discusses tracking control of multi-link flexible manipulators, vibration control of flexible buildings under natural disasters, and fault-tolerant control of bionic flexible flapping-wing aircraft and addresses common challenges like external disturbances, dynamic uncertainties, output constraints, and actuator faults. Expanding on its theoretical deliberations, this book includes many case studies demonstrating how the proposed approaches work in practice. Experimental investigations are carried out on Quanser Rotary Flexible Link, Quanser 2 DOF Serial Flexible Link, Quanser Active Mass Damper, and Quanser Smart Structure platforms. This book starts by providing an overview of dynamic modeling and intelligent control of flexible systems, introducing several important issues in the study of flexible systems, along with modeling and control methods of three typical flexible systems. Other topics include: Foundational mathematical preliminaries including the Hamilton principle, model discretization methods, Lagrange's equation method, and Lyapunov's stability theorem Dynamic modeling of a single-link flexible robotic manipulator and vibration control design for a string with the boundary time-varying output constraint Unknown time-varying disturbances, such as earthquakes and strong winds, and how to suppress them and use MATLAB and Quanser to verify effectiveness of a proposed control Adaptive vibration control methods for a single-floor building-like structure equipped with an active mass damper (AMD) Dynamic Modeling and Neural Network-Based Intelligent Control of Flexible Systems is an invaluable resource for researchers and engineers seeking high-efficiency modeling methods and neural-network-based control solutions for flexible systems, along with industry engineers and researchers who are interested in control theory and applications and students in related programs of study.




Nonlinear Dynamics and Vibration Control of Flexible Systems


Book Description

This book is an essential guide to nonlinear dynamics and vibration control, detailing both the theory and the practical industrial applications within all aspects of engineering. Demonstrating how to improve efficiency through reducing unwanted vibration, it will aid both students and engineers in practically and safely improving flexible structures through control methods. Increasing demand for light-weight robotic systems and space applications has actuated the design and construction of more flexible structures. These flexible structures, involving numerous dynamic systems, experience unwanted vibrations, impacting accuracy, operating speed, safety and, importantly, efficiency. This book aids engineers in assuaging this issue through vibration control methods, including nonlinear dynamics. It covers topics such as dynamic modeling of nonlinear system, nonlinear oscillators, and modal analyses of multiple-mode system. It also looks at vibration control methods including linear control, nonlinear control, intelligent control, and command smoothers. These control methods are effective and reliable methods to counteract unwanted vibrations. The book is practically minded, using industrial applications throughout, such as bridge cranes, tower cranes, aerial cranes and liquid sloshing. It also discusses cable-suspension structures, light-weight links, and fluid motions which exhibit flexible-structure dynamics. The book will be of interest to students and engineers alike, in the field of mechatronics, mechanical systems and signal processing, nonlinear dynamics, vibration, and control engineering.




Reinforcement Learning and Dynamic Programming Using Function Approximators


Book Description

From household appliances to applications in robotics, engineered systems involving complex dynamics can only be as effective as the algorithms that control them. While Dynamic Programming (DP) has provided researchers with a way to optimally solve decision and control problems involving complex dynamic systems, its practical value was limited by algorithms that lacked the capacity to scale up to realistic problems. However, in recent years, dramatic developments in Reinforcement Learning (RL), the model-free counterpart of DP, changed our understanding of what is possible. Those developments led to the creation of reliable methods that can be applied even when a mathematical model of the system is unavailable, allowing researchers to solve challenging control problems in engineering, as well as in a variety of other disciplines, including economics, medicine, and artificial intelligence. Reinforcement Learning and Dynamic Programming Using Function Approximators provides a comprehensive and unparalleled exploration of the field of RL and DP. With a focus on continuous-variable problems, this seminal text details essential developments that have substantially altered the field over the past decade. In its pages, pioneering experts provide a concise introduction to classical RL and DP, followed by an extensive presentation of the state-of-the-art and novel methods in RL and DP with approximation. Combining algorithm development with theoretical guarantees, they elaborate on their work with illustrative examples and insightful comparisons. Three individual chapters are dedicated to representative algorithms from each of the major classes of techniques: value iteration, policy iteration, and policy search. The features and performance of these algorithms are highlighted in extensive experimental studies on a range of control applications. The recent development of applications involving complex systems has led to a surge of interest in RL and DP methods and the subsequent need for a quality resource on the subject. For graduate students and others new to the field, this book offers a thorough introduction to both the basics and emerging methods. And for those researchers and practitioners working in the fields of optimal and adaptive control, machine learning, artificial intelligence, and operations research, this resource offers a combination of practical algorithms, theoretical analysis, and comprehensive examples that they will be able to adapt and apply to their own work. Access the authors' website at www.dcsc.tudelft.nl/rlbook/ for additional material, including computer code used in the studies and information concerning new developments.




Active Vibration Control and Stability Analysis of Flexible Beam Systems


Book Description

This book presents theoretical explorations of several fundamental problems in the dynamics and control of flexible beam systems. By integrating fresh concepts and results to form a systematic approach to control, it establishes a basic theoretical framework. It includes typical control design examples verified using MATLAB simulation, which in turn illustrate the successful practical applications of active vibration control theory for flexible beam systems. The book is primarily intended for researchers and engineers in the control system and mechanical engineering community, offering them a unique resource.




Nonlinear Vibration with Control


Book Description

This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader themes cut across these application areas: (i) vibration suppression – or active damping – and, (ii) adaptive structures and machines. In this expanded 2nd edition, revisions include: An additional section on passive vibration control, including nonlinear vibration mounts. A more in-depth description of semi-active control, including switching and continuous schemes for dampers and other semi-active systems. A complet e reworking of normal form analysis, which now includes new material on internal resonance, bifurcation of backbone curves and stability analysis of forced responses. Further analysis of the nonlinear dynamics of cables including internal resonance leading to whirling. Additional material on the vibration of systems with impact friction. The book is accessible to practitioners in the areas of application, as well as students and researchers working on related topics. In particular, the aim is to introduce the key concepts of nonlinear vibration to readers who have an understanding of linear vibration and/or linear control, but no specialist knowledge in nonlinear dynamics or nonlinear control.




Dynamic Modeling and Vibration Control of a Single-link Flexible Manipulator Using a Combined Linear and Angular Velocity Feedback Controller


Book Description

The use of lightweight, thin flexible structures creates a dilemma in the aerospace androbotic industries. While increased operating efficiency and mobility can be achieved byemploying such structures, these benefits are compromised by significant structuralvibrations due to the increased flexibility. To address this problem, extensive research inthe area of vibration control of flexible structures has been performed over the last twodecades. The majority of the research has been based on the use of discrete piezoceramicactuators (PZTs) as active dampers, as they are commercial availability and have highforce and bandwidth capabilities. Many different active vibration control strategies havepreviously been proposed, in order to effectively suppress vibrations. The synthesizedvibration controllers will be less effective or even make the system to become unstable ifthe actuator locations and control gains are not chosen properly. However, there iscurrently no quantitative procedure that deals with these procedures simultaneously. This thesis presents a theoretical and numerical study of vibration control of a singlelinkflexible manipulator attached to a rotating hub, with PZTs bonded to the surface ofthe link. A commercially available fibre optic sensor called ShapeTapeTM is introduced asa new feedback sensing technique, which is complemented by a quantitative anddefinitive model based procedure for selecting the individual PZT locations and gains. Based on Euler-Bernoulli beam theory, discrete finite element equations are obtainedusing Lagrange's equations for a PZT-mounted beam element. Slewing of the flexiblelink by a rotating hub induces vibrations in the link that persist long after the hub stopsrotating. These vibrations are suppressed through a combined scheme of PD-based hubmotion control and proposed PZT actuator control, which is a composite linear (L-type)and angular (A-type) velocity feedback controller. A Lyapunov approach was used tosynthesize the PZT controller. The feedback sensing of linear and angular velocities isrealized by using the ShapeTapeTM, which measures the bend and twist of the flexiblelink's centerline. Both simulation and experimental results show that tip vibrations aremost effectively suppressed using the proposed composite controller. Its performanceadvantage over the individual linear or angular velocity feedback controllers confirmstheoretical predictions made based on a non-proportional damping model of the PZTeffects. Furthermore, it is demonstrated that the non-proportional nature of the PZTdamping effect must be considered in order to bound the range of allowable controllergain values.




Vibration Reduction for Flexible Structures by Smoothing Commands


Book Description

This book described vibration reduction for flexible structures by the command smoothing techniques. The Command smoothing technique is a kind of open-loop controller. The operator's commands filter through a piecewise continuous function, called smoother, to produce smoothed commands. Smoothed commands move flexible dynamic systems toward desired positions with minimal oscillations. Five types of command smoother were reported including one-piece, two-pieces, three-pieces, and four-pieces smoothers, and the smoother for multi-mode Duffing oscillators. All smoothers are robust to changes in the system parameters and working conditions. The command smoothing technique has been successfully applied to industrial cranes, sloshing suppression, flexible manipulators, high-speed cam and follower systems, and helicopter slung loads.