Model-based controller design for a plastic film extrusion process

This paper reports the development and implementation of a model-based cross-directional controller for plastic film extrusion and other web-forming processes. The controller design has a similar structure to that of internal model control (IMC) with the addition of an observer whose gain is designed to minimise process and model mis-match. The observer gain is obtained by solving a multi-objective optimisation through the application of a genetic algorithm and simulation results are presented in this paper demonstrating improvements that can be achieved by the proposed controller over two existing CD controllers

Modeling and control of a plastic film manufacturing web process

This paper is concerned with the modelling of aplastic film manufacturing process and the development and implementation of a model-based Cross-Directional (CD) controller. The model is derived from first-principles and some empirical relationships. The final validated nonlinear model could provide a useful off-line platform for developing control and monitoring algorithms.A new controller is designed which has a similar structureto that of Internal Model Control (IMC) with the addition ofan observer whose gain is designed to minimise process andmodel mis-match. The observer gain is obtained by solving amulti-objective optimisation problem through the application of a genetic algorithm. The controller is applied to the nonlinear model and simulation results are presented demonstrating improvements that can be achieved by the proposed controller over two existing CD controllers

Middleware and Architecture for Advanced Applications of Cyber-physical Systems

In this thesis, we address issues related to middleware, architecture and applications of cyber-physical systems. The first problem we address is the cross-layer design of cyber-physical systems to cope with interactions between the cyber layer and the physical layer in a dynamic environment. We propose a bi-directional middleware that allows the optimal utilization of the common resources for the benefit of either or both the layers in order to obtain overall system performance. The case study of network connectivity preservation in a vehicular formation illustrates how this approach can be applied to a particular situation where the network connectivity drives the application layer. Next we address another aspect of cross-layer impact: the problem that arises when network performance, in this case delay performance, affects control system performance. We propose a two-pronged approach involving a flexible adaptive model identification algorithm with outlier rejection, which in turn uses an adaptive system model to detect and reject outliers, thus shielding the estimation algorithm and thereby improving reliability. We experimentally demonstrate that the outlier rejection approach which intercepts and filters the data, combined with simultaneous model adaptation, can result in improved performance of Model Predictive Control in the vehicular testbed. Then we turn to two advanced applications of cyber-physical systems. First, we address the problem of security of cyber-physical systems. We consider the context of an intelligent transportation system in which a malicious sensor node manipulates the position data of one of the autonomous cars to deviate from a safe trajectory and collide with other cars. In order to secure the safety of such systems where sensor measurements are compromised, we employ the procedure of “dynamic watermarking”. This procedure enables an honest node in the control loop to detect the existence of a malicious node within the feedback loop. We demonstrate in the testbed that dynamic watermarking can indeed protect cars against collisions even in the presence of sensor attacks. The second application of cyber-physical systems that we consider is cyber-manufacturing which is an origami-type laser-based custom manufacturing machine employing folding and cutting of sheet material to manufacture 3D objects. We have developed such a system for use in a laser-based autonomous custom manufacturing machine equipped with real-time sensing and control. The basic elements in the architecture are a laser processing machine, a sensing system to estimate the state of the workpiece, a control system determining control inputs for a laser system based on the estimated data, a robotic arm manipulating the workpiece in the work space, and middleware supporting the communication among the systems. We demonstrate automated 3D laser cutting and bending to fabricate a 3D product as an experimental result. Lastly, we address the problem of traffic management of an unmanned aerial system. In an effort to improve the performance of the traffic management for unmanned aircrafts, we propose a probability-based collision resolution algorithm. The proposed algorithm analyzes the planned trajectories to calculate their collision probabilities, and modifies individual drone starting times to reduce the probability of collision, while attempting to preserve high performance. Our simulation results demonstrate that the proposed algorithm improves the performance of the drone traffic management by guaranteeing high safety with low modification of the starting times

DEVELOPMENT OF A BIAXIAL LOADING FRAME FOR THIN SHEET CRUCIFORM SPECIMENS

Characterization of the evolving yield loci and forming limit diagrams for sheet materials under biaxial loading is necessary for the development of accurate sheet metal forming process simulations. Biaxial tension testing has been shown to have significant advantages over the current computational and experimental methods for such material characterization; however, the few commercially available loading frames are far too large and expensive to be practical for most metal forming research laboratories. To address this problem, the University of New Hampshire’s Mechanics, Materials, and Manufacturing Lab is working to design a practical servohydraulic biaxial loading frame for such metal forming laboratories. The physical system design, fabrication, and component selection was performed previously by a team of mechanical engineering seniors in collaboration with Greenerd Press and Machine Co. To continue the project, this thesis presents the design, implementation, and validation of a PLC-based control system and LabVIEW graphical interface for operating the biaxial loading frame. Experimental data shows that the displacement control system can accurately maintain equal displacement of opposing actuators to within 0.1[mm] for fixed position, 80[mm/min] ramp, and 0.2[Hz] sinusoidal profiles. The selection and mounting position of the hydraulic control valves were found to be the major limiting factor in the abilities of the control system. Preliminary uniaxial and biaxial tension tests with Al-6022-T4 show inconsistent stress-strain responses that cause differing force measurements of up to 8[%] between opposing load cells. The inconsistencies were attributed to the mechanical design of the current frame of the testing machine. Corresponding mechanical, hydraulic, and software/control design improvements are suggested, and plans for the future of the project are discussed

Process And Apparatus For Removing Water From Materials Using Oscillatory Flow-reversing Gaseous Media

A process and an apparatus for removing water from a material are disclosed. The material can be selected from the group consisting of fibrous webs, textiles, plastics, non-woven webs, building materials, or any combination thereof, and may comprise an agricultural product, a food product, a pharmaceutical product, a biotechnology product, etc. The process comprises providing a material; providing an oscillatory flow-reversing impingement gaseous media having predetermined frequency; providing a gas-distributing system designed to emit the oscillatory flow-reversing impingement gas onto the material; and impinging the oscillatory flow-reversing gas onto the material, thereby removing moisture from the material.The apparatus comprises a support to receive the material and to carry said material in a machine direction; a pulse generator producing oscillatory flow-reversing air or gas; and a gas-distributing system in fluid communication with the pulse generator for delivering the oscillatory flow-reversing gas to the material, wherein the gas-distributing system terminates with at least one discharge outlet juxtaposed with the support.Institute Of Paper Science And Technology, Inc

Softsensors: key component of property control in forming technology

The constantly increasing challenges of production technology for the economic and resource-saving production of metallic workpieces require, among other things, the optimisation of existing processes. Forming technology, which is confronted with new challenges regarding the quality of the workpieces, must also organise the individual processes more efficiently and at the same time more reliably in order to be able to guarantee good workpiece quality and at the same time to be able to produce economically. One way to meet these challenges is to carry out the forming processes in closed-loop control systems using softsensors. Despite the many potential applications of softsensors in the field of forming technology, there is still no definition of the term softsensor. This publication therefore proposes a definition of the softsensor based on the definition of a sensor and the distinction from the observer, which on the one hand is intended to stimulate scientific discourse and on the other hand is also intended to form the basis for further scientific work. Based on this definition, a wide variety of highly topical application examples of various softsensors in the field of forming technology are given

Middleware and Architecture for Advanced Applications of Cyber-physical Systems

In this thesis, we address issues related to middleware, architecture and applications of cyber-physical systems. The first problem we address is the cross-layer design of cyber-physical systems to cope with interactions between the cyber layer and the physical layer in a dynamic environment. We propose a bi-directional middleware that allows the optimal utilization of the common resources for the benefit of either or both the layers in order to obtain overall system performance. The case study of network connectivity preservation in a vehicular formation illustrates how this approach can be applied to a particular situation where the network connectivity drives the application layer. Next we address another aspect of cross-layer impact: the problem that arises when network performance, in this case delay performance, affects control system performance. We propose a two-pronged approach involving a flexible adaptive model identification algorithm with outlier rejection, which in turn uses an adaptive system model to detect and reject outliers, thus shielding the estimation algorithm and thereby improving reliability. We experimentally demonstrate that the outlier rejection approach which intercepts and filters the data, combined with simultaneous model adaptation, can result in improved performance of Model Predictive Control in the vehicular testbed. Then we turn to two advanced applications of cyber-physical systems. First, we address the problem of security of cyber-physical systems. We consider the context of an intelligent transportation system in which a malicious sensor node manipulates the position data of one of the autonomous cars to deviate from a safe trajectory and collide with other cars. In order to secure the safety of such systems where sensor measurements are compromised, we employ the procedure of “dynamic watermarking”. This procedure enables an honest node in the control loop to detect the existence of a malicious node within the feedback loop. We demonstrate in the testbed that dynamic watermarking can indeed protect cars against collisions even in the presence of sensor attacks. The second application of cyber-physical systems that we consider is cyber-manufacturing which is an origami-type laser-based custom manufacturing machine employing folding and cutting of sheet material to manufacture 3D objects. We have developed such a system for use in a laser-based autonomous custom manufacturing machine equipped with real-time sensing and control. The basic elements in the architecture are a laser processing machine, a sensing system to estimate the state of the workpiece, a control system determining control inputs for a laser system based on the estimated data, a robotic arm manipulating the workpiece in the work space, and middleware supporting the communication among the systems. We demonstrate automated 3D laser cutting and bending to fabricate a 3D product as an experimental result. Lastly, we address the problem of traffic management of an unmanned aerial system. In an effort to improve the performance of the traffic management for unmanned aircrafts, we propose a probability-based collision resolution algorithm. The proposed algorithm analyzes the planned trajectories to calculate their collision probabilities, and modifies individual drone starting times to reduce the probability of collision, while attempting to preserve high performance. Our simulation results demonstrate that the proposed algorithm improves the performance of the drone traffic management by guaranteeing high safety with low modification of the starting times

A New Atomization Paradigm: Smart Wave-Augmented Varicose Explosions

The characterization of viscous, non-Newtonian slurry heating and atomization by means of internal wave excitation is presented for a twin-fluid injector. We detail mechanisms that enhance their disintegration in a novel process called “Wave-Augmented Varicose Explosions” (WAVE). Atomization of such fluids is challenging, especially at low gas-liquid mass ratios. Droplet production is further complicated when slurry viscosity varies widely; if viscosity levels are too high, atomization quality suffers, and an undesirable pressure drop restricts the flow. To mitigate, we introduce and demonstrate “Smart” atomization, a novel implementation of simultaneous proportional integral derivative (PID) control algorithms to accommodate dynamically and extensively changing fluid properties. Unlike a conventional twin-fluid injector, WAVE injects a cold annular slurry flow into a hot core steam flow, encouraging regular slurry waves to form inside the nozzle and producing bulk system pulsation at 1000 Hz. The Kelvin-Helmholtz instability dominates during wave formation, while transonic pressure effects dominate during wave collapse. Numerical simulations reveal three atomization mechanisms that are a direct result of wave formation: 1) wave impact momentum, 2) pressure buildup, and 3) droplet breakaway. The first two are the forces that exploit slurry irregularities to drive rupture. The third occurs as rising waves penetrate the central steam flow and droplets are stripped off. Two effervescent mechanisms are also provided as 1) surface deformation allows steam fingers to force through the wave, and 2) the wave collapses on itself, trapping steam. Both Rayleigh-Taylor and Kelvin-Helmholtz instabilities are self-amplified in a viscosity-shear-temperature instability cycle because the slurry’s viscosity is sensitive to both strain and temperature. Smart atomization is applied to the WAVE framework with two coupled PID controllers to improve atomization robustness. The first controller automates slurry flow based on atomizer pressure drop, while the second compensates for the newly adjusted phase momentum ratio and sets a new steam flow based on droplet size. Three tests with increasingly rigorous models were conducted to capture the response of this coupled controller system to a step increase in viscosity. Though atomization characteristics were drastically altered, for a 100-fold increase in slurry viscosity, the controllers successfully maintained consistent droplet size and slurry flow resistance