Web Winding Systems Research Articles

Synchronization Mechanism for Controlled Complex Networks under Auxiliary Effect of Dynamic Edges

The scope of complex dynamical networks (CDNs) with dynamic edges is very wide, as it is composed of a class of realistic networks including web-winding systems, communication networks, neural networks, etc. However, a classic research topic in CDNs, the synchronization control problem, has not been effectively solved for CDNs with dynamic edges. This paper will investigate the emergence mechanism of synchronization from the perspective of large-scale systems. Firstly, a CDN with dynamic edges is conceptualized as an interconnected coupled system composed of an edge subsystem (ES) and a node subsystem (NS). Then, based on the proposed improved directed matrix ES model and expanded matrix inequality, this paper overcomes the limitations of coupling term design in node models and the strong correlation of tracking targets between nodes and edges. Due to the effect of the synthesized node controller and the auxiliary effect of the ES, state synchronization can be realized in the CDN. Finally, through simulation examples, the validity and advantages of our work compared to existing methods are demonstrated.

Enhanced Reliability for Winding Machine via New Fault Tolerant Control Based on RST-Backstepping Controller

Abstract Due to the external disturbances, model uncertainties, strong coupling, and occurred faults, the winding machine presents a great control challenge. In order to deal with these problems, this paper presents the formulation of a novel scheme of fault tolerant control (FTC) for three-motor web-winding systems; it is concerned with the nonlinear robust backstepping control based on the combination of RST and backstepping controllers where the process is modelled by a nonlinear model. The main contribution of the paper is that the approach developed here summarises the performance of RST and backstepping controllers in order to design a robust controller capable of eliminating external disturbances and sensor faults affecting the system. The stability of the whole system is proven using the Lyapunov theory. Finally, analysis in comparison with the conventional backstepping controller and simulations in the MATLAB environment are accomplished to confirm the efficiency of the proposed method.

Robust fault estimation and fault tolerant control for three-motor web-winding systems

This paper studies the problems of fault estimation and fault tolerant control for three-motor web-winding systems in the presence of multiple disturbances and actuator faults. A disturbance compensation-based fault estimation observer is designed to estimate the system actuator faults. By setting the reference outputs, a method of obtaining equilibrium control inputs and equilibrium states is formulated to achieve the variation dynamic model at equilibrium points by Taylor expansion. Then, based on the estimated actuator faults, an effective fault tolerant control strategy is proposed by the methods of interval matrix and disturbance local compensation. Sufficient conditions of asymptotic stability of the estimation error system and the closed-loop system are derived based on the Lyapunov theory. Fault estimation observer and fault tolerant controller gain matrices are obtained by solving the linear matrix inequalities. Finally, simulations and analysis are performed to verify the effectiveness of the proposed method.

Distributed fault tolerant tracking control for large‐scale multi‐motor web‐winding systems

This study is concerned with the distributed fault tolerant tracking control for large-scale multi-motor web-winding systems. Firstly, the web-winding system is considered a synthetic system with several dynamic subsystems subject to multiple disturbances and actuator faults. Then, a disturbance compensation-based distributed fault diagnosis scheme is developed to estimate the system actuator faults. By setting the reference outputs, a method of obtaining equilibrium control inputs and equilibrium states is formulated to achieve the distributed variation dynamic model at equilibrium points by Taylor expansion. Based on the estimated actuator faults, an effective distributed fault tolerant control strategy is proposed by the techniques of interval matrix and disturbance local compensation. Sufficient conditions of asymptotic stability of the estimation error systems and the closed-loop systems are derived based on the Lyapunov theory. A fault diagnosis observer and a fault tolerant controller gain matrices are obtained by solving the linear matrix inequalities. Finally, simulations and analysis are performed on the three-motor web-winding system to verify the effectiveness of the proposed distributed fault tolerant control strategy.

Robust Distributed Fault Diagnosis for Large-Scale Interconnected Multi-Motor Web-Winding Systems

Web-winding systems are generally large-scale interconnected systems with many motor-driven subsystems. If the centralized fault diagnosis methods are adopted, the information exchanges among the motor driven subsystems will be required. However, the information exchanges are not always available due to the communication restriction, high system cost and so on. Moreover, it will lead to the high computational cost. To solve this problem well, the web-winding system is considered as a synthetic system with several dynamic subsystems subjected to multiple disturbances and actuator faults. Then, the methods of disturbance attenuation based distributed fault diagnosis method and disturbance compensation based distributed fault diagnosis method are developed to estimate the actuator faults. The objective of fault detection, fault isolation and fault estimation can also be realized via these methods. Meanwhile, sufficient conditions of asymptotic stability of the estimation error system are derived based on the Lyapunov theory. Observer gain matrices are obtained by solving the linear matrix inequalities (LMIs). Finally, simulations and analysis are performed on the three-motor web-winding system to verify the effectiveness of the proposed two fault diagnosis methods.

Decentralized coordinated control of elastic web winding systems without tension sensor

In elastic web winding systems, precise regulation of web tension in each span is critical to ensure final product quality, and to achieve low cost by reducing the occurrence of web break or fold. Generally, web winding systems use load cells or swing rolls as tension sensors, which add cost, reduce system reliability and increase the difficulty of control. In this paper, a decentralized coordinated control scheme with tension observers is designed for a three-motor web-winding system. First, two tension observers are proposed to estimate the unwinding and winding tension. The designed observers consider the essential dynamic, radius, and inertial variation effects and only require the modest computational effort. Then, using the estimated tensions as feedback signals, a robust decentralized coordinated controller is adopted to reduce the interaction between subsystems. Asymptotic stabilities of the observer error dynamics and the closed-loop winding systems are demonstrated via Lyapunov stability theory. The observer gains and the controller gains can be obtained by solving matrix inequalities. Finally, some simulations and experiments are performed on a paper winding setup to test the performance of the designed observers and the observer-base DCC method, respectively.

Robust decentralized control for large-scale web-winding systems: A linear matrix inequality approach

In this paper, a robust decentralized control scheme is proposed for web-winding systems. The control input for each subsystem is divided into two parts, a reference control input and a control compensation. First, the reference control inputs and the error dynamic models are presented. Then, based on the error dynamic model, a decentralized controller is designed to compute the control compensation, and the relevant sufficient condition for the existence of the decentralized controller is derived in terms of linear matrix inequalities (LMIs). By virtue of regarding some parameters as interval variables, the proposed controller has good robustness with regard to parameter variations and is adapted to the changes of set point. Finally, a three-motor web-winding system is considered as an application example, and simulation and experimental tests illustrate the effectiveness of the proposed controller.

Modeling and Simulation Multi Motors Web Winding System

Web winding systems allow the operations of unwinding and rewinding of various products including plastic films, sheets of paper, sheets, and fabrics. These operations are necessary for the development and the treatment of these products. Web winding systems generally consist of the same machine elements in spite of the diversity of the transported products. Due to the wide rang variation of the radius and inertia of the rollers the system dynamic change considerably during the winding/ unwinding process. Decentralized PI controller for web tension control and linear speed control are presented in this paper. The PI control method can be applied easily and is widely known, it has an important place in control applications. Simulation results show the effectiveness of the proposed linear speed and tension controller for web winding multi motors systems.

Disturbance Rejection in Parameter-varying Web-winding Systems

We propose a control scheme to reject disturbances in web tension that are caused by reel eccentricities in parameter-varying web-winding systems. When the web winds from one reel to the other, the nominal reel radii vary. In addition to this, the reels are not perfectly circular and the eccentricities introduce disturbances to the tension output. If the web is thin enough, in a certain time span, the nominal reel radii can be considered as constants and the reel eccentricities are periodic. In our design, the entire web winding process in which the whole pack of web winds from a full source reel to an empty take-up reel is investigated at a certain number of operating points. At each operating point, an adaptive controller that synthesizes the inverse input whose system response cancels the disturbances is developed. Gain-scheduling control is then used between different operating points. The scheme is simulated on a decoupled tension loop of an example reel-to-reel web-winding system that represents a digital tape system.

FIXED – ORDER AND STRUCTURE H∞ CONTROL WITH MODEL BASED FEEDFORWARD FOR ELASTIC WEB WINDING SYSTEMS

In web transport systems, the main concern is to control independently speed and tension in spite of perturbations such as radius variations and changes of setting point. This paper presents the application of nonsmooth nonconvex optimization techniques to design centralized fixed order and decentralized fixed order and fixed structure H∞ controllers with model based feedforward for web winding systems. The approach provides improved web tension and velocity regulation. First, mathematical models of fundamental elements in a web process line are presented. A state space model is developed which enables calculation of the phenomenological model feedforward signals and helps in the synthesis of H∞ controllers around the set points given by the reference signals. The H∞ control strategies with additive feedforward have been validated on a nonlinear simulator identified on a 3-motor winding test bench.

Robust Control of Nonlinear Tape Transport Systems With and Without Tension Sensors

Web-winding systems, such as tape drives, are often modeled as linear and time-invariant, but at least two nonlinearities are common in these systems. First, the reel radii and moments of inertia change as web media spools from one reel to another. Second, friction can draw a thin layer of air between the layers of web media wrapped on the take-up reel, making the system’s spring and damping characteristics nonlinear by allowing a greater length of media to vibrate freely. In addition to these nonlinearities, there is often uncertainty in the motor parameters. In the first part of this paper, feedback linearization ideas motivate state feedback and changes of variables that transform the system into decoupled and intuitively meaningful tension and velocity loops. For the case where tension measurements are available, Lyapunov redesign techniques are then used to develop control laws that are robust with respect to these nonlinearities and uncertainties. The second part of this paper then develops an observer-based controller for the case where no tension measurements are available. Performance is established analytically for both the measurement-based and observer-based schemes. Simulations illustrate this performance.

Time-Optimal Control of Web-Winding Systems With Air Entrainment

Models of web-winding systems such as tape drives often ignore the phenomenon of air entrainment, in which friction can draw a thin layer of air many layers deep into the web media wrapped on the takeup reel. Air entrainment allows a greater length of the media to vibrate freely and thus changes the spring and damping characteristics of the system and results in nonlinearities. This paper first explores the structure of nonlinear models for air entrainment and proposes one such model for tape systems. Without specifying a particular air entrainment model, time-optimal inputs for transient maneuvers are explored for the cases of constant- and varying-tension trajectories. These inputs are useful for determining the effect of air entrainment (and the utility of modeling it) on a given system and for establishing bounds on performance for a given system. Simulations illustrate these results on an example tape system.

An improved linear fractional model for robustness analysis of a winding system

Web winding systems exhibit nonlinear dynamics and their behaviors vary with respect to several quantities such as elasticity modulus and end roll radii. Being able to guarantee that the system remains stable during the whole winding process when parameters vary appears to be crucial. μ-analysis is a classical technique for evaluating robustness of parameter-dependent systems and is used herein. It requires the model to be under the ad hoc form of a linear fractional representation. Following the physics equations, the different steps are detailed until to come to the ad hoc model including parameters with independent variations. Notably, the nonlinear dependence between the winder and unwinder radii is considered. Numerical results are given in the case where the system is driven by a H ∞ controller.

Transient Control of Web-Winding Systems with Air Entrainment

Models of web-winding systems such as tape drives often ignore the phenomenon of air entrainment, in which friction can draw a thin layer of air many layers deep into the web media wrapped on the takeup reel. Air entrainment allows a greater length of the media to vibrate freely, and thus changes the spring and damping characteristics of the system and results in nonlinearities. This paper first explores the structure of nonlinear models for air entrainment, and proposes one such model for tape systems. Time-optimal inputs for transient maneuvers are explored for the cases of constant- and varying-tension trajectories. It is concluded that when tension is held constant, inputs which are optimal for the common linear model are also optimal for virtually any reasonable air entrainment model. When tension is allowed to vary, optimal inputs are bang-bang. Simulations illustrate these results on an example tape system.