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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / A computational system was developed to support data collection for advanced airborne technology research. Basic research is conducted using a variety of sensing devices for collection of flight characteristics data from aircraft. To maximize control over as many variables as possible during research activities, a controlled aircraft tracking environment is needed to provide reference data for real-time operation and post-mission analysis. The solution to this requirement is realized with the ACMI Interface System (ACINTS). The ACINTS extracts real-time tracking data from a closed-loop telemetered tracking array, reprocesses needed parameters, provides reference data (positioning and control commands) to the sensor device, and records aircraft kinematics for later correlation with other collected data.

An ideal polymerase chain reaction (PCR) system should be capable of rapidly amplifying a wide range of targets in both single and multiplex formats. Unfortunately, the timescales and complexities involved in many existing technologies impose significant limitations on achievable throughput. Buoyancy driven PCR is emerging as a simplified version of thermally driven bio-analysis systems. Here, we demonstrate a simplified convectively driven thermocycler capable of performing single and multiplex PCR for amplicons ranging from 191 bp to 1.3 kb within 10 to 50 minutes using 10 to 25 µL reaction volumes. By positioning two independent thermoelectric heating elements along the perimeter of a flow loop reactor constructed using ordinary plastic tubing, a buoyancy-driven flow is established that continuously circulates reagents through temperature zones associated with the PCR process. Unlike conventional benchtop thermocyclers, this arrangement allows reactions to be performed without the need for dynamic temperature control of inactive hardware components while maintaining comparable product yields and requiring no modifications to standard PCR protocols. We also provide a general correlation that can be applied to design reactor geometries satisfying virtually any combination of reagent volume and cycling time. In addition to offering an attractive combination of cost and performance, this system is readily adaptable for portable battery powered operation, making it feasible to perform PCRbased assays in a broader array of settings.

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This thesis is concerned with subspace identification and its applications for controller performance assessment and process modeling from closed-loop data. A joint input-output closed-loop subspace identification method is developed which provides consistent estimation of the subspace matrices and the noise covariance matrix required for the LQG benchmark curve estimation. Subspace LQG benchmark is also used for performance assessment of the cascade supervisory-regulatory control systems. Three possible scenarios for LQG control design and performance improvement are discussed for this structure. A closed-loop subspace identification method is also provided for estimation of the subspace matrices necessary for performance assessment. A method of direct step model estimation from closed-loop data is provided using subspace identification. The variance calculation required for this purpose can be performed using the proposed method. The variances are used for weighted averaging on the estimated Markov parameters to attenuate the noise influence on the final step response estimation. / Process Control

Supply chain management has evolved over the course of history in order to provide faster and efficient service to those companies that follow its principles. As there have been advances in technology and changes in the way business is conducted across the globe, supply chains also have had to change in order to remain effective. With greater attention paid to resource depletion, environmental impact, and waste reduction; the concept of closed-loop supply chains has garnered the attention of managers who look to make their production processes more efficient. Finding ways to judge the performance of these supply chains is critical to managers. By identifying key performance measures, they are able to gauge how their closed-loop process is performing as well as identify areas for improvement.

A dynamic real-time optimization (DRTO) formulation with closed-loop prediction is used to coordinate distributed model predictive controllers (MPCs) by rigorously predicting the interaction between the distributed MPCs and full plant response in the DRTO formulation. This results a multi-level optimization problem and that is solved by replacing the MPC quadratic programming subproblems by their equivalent Karush-Kuhn-Tucker (KKT) first-order optimality conditions to yield a single-level mathematical program with complementarity constraints (MPCC). The proposed formulation is able to perform both target tracking and economic optimization with significant performance improvement over decentralized control, and similar performance to centralized MPC. A linear dynamic case study illustrates the performance of the proposed strategy for coordination of distributed MPCs for different levels of plant interaction,. The method is thereafter applied to a nonlinear integrated plant with recycle, where its performance in both set-point target tracking and economic optimization is demonstrated. Subsequently, this study presents two techniques for approximation of the closed-loop prediction within the DRTO formulation - a hybrid closed-loop formulation and an input clipping formulation. The hybrid formulation generates closed-loop predictions for a limited number of time intervals along the DRTO prediction horizon, followed by an open-loop optimal control formulation extended to rest of the horizon. The input clipping formulation utilizes an unconstrained MPC optimization formulation for each distributed MPC, coupled with the application of an input saturation mechanism. The performance of the approximation techniques is evaluated through application to case studies based on linear and nonlinear dynamic plant models respectively. The approximation techniques are demonstrated to be more computationally efficient than than the rigorous counterpart without significant loss in performance. The performance of the proposed DRTO formulation can be further improved by the introduction of nonlinearity. The nonlinear dynamic plant model is firstly introduced in the DRTO formulation while maintaining the linear formulation for the distributed MPCs. The performance of resulting formulation is demonstrated and compared against the linear counterpart. The nonlinear MPC formulation is then included in both lower-level control implementation and DRTO formulation. By reformulating the Lagrangian of the nonlinear MPC optimization subproblems, the nonlinear MPC formulation is successfully implemented in the DRTO formulation. The performance of such DRTO formulation is further improved and shown using a nonlinear case study. The conclusion of this study is summarized and the potential directions of this research such as large-scale applications, variation of MPC implementations, and robust model-based control are outlined and explained in the end. / Thesis / Master of Applied Science (MASc)

Wafer handling robotics are critical in semiconductor manufacturing to enable tight control of temperature, humidity, and particle contamination during processing. Closed-loop dynamic modeling during the robot design process ensures designs meet throughput and stability specifications prior to prototype hardware purchase. Dynamic models are also used in model-based control to improve performance. This thesis describes the generation and mathematical verification of a dynamic model for a three degrees-of-freedom wafer handling mechanism with one linear and two rotary axes. The dynamic plant model is integrated with motion and motor controller models, and the closed-loop performance is compared with experimental data. Models with rigid and flexible connections are compared, and the flexible connection models are shown to overall agree better with a measured step response. The simulation time increase from the addition of flexible connections can be minimized by modeling only the component stiffnesses that impact the closed-loop mechanism response. A method for selecting which elements to include based on controller bandwidth is presented and shown to significantly improve simulation times with minimal impact on model predictive performance.

Idag slängs en stor del av konsumenters använda textilprodukter i soptunnan för att sedan deponeras i stora sopområden, så kallade landfills. Vad många inte känner till är att en stor del av det som slängs egentligen går att återanvända. Genom att ta vara på nyttjade produkter kan företag minska användningen av råmaterial i produktion för att på sikt uppnå en sluten produktlivscykel. Syftet med den här uppsatsen är att, med hjälp av en kvalitativ ansats, undersöka hur textilföretag arbetar med att erhålla nyttjade produkter från konsumenten och återföra de tillbaka in i företaget. Genom att studera tidigare forskning inom området har vi identifierat fem nyckelprocesser i produktens väg från konsumenten tillbaka till företaget. Processerna är följande: Produktinsamling, Returlogistik, Sortering och disponering, Återanvändningsalternativ samt Omdistribution, vilka dessutom är de huvudområden som presenteras i den teoretiska referensramen. Den teoretiska referensramen mynnar ut i en syntesmodell som framtagits för att utföra en jämförande analys av empirin. Rapportens empiri har samlats in genom semi-strukturerade intervjuer. Resultatet av insamlad empiri från intervjuer bör bidra till ett mer uppdaterat synsätt på vilka utmaningar som textila företag, som har implementerat en Closed-loop Supply Chain, står inför. Förhoppningsvis kommer resultatet att frambringa lösningar för textilföretag som önskar förlänga eller stänga sina produktlivscykler. Studien granskar tre svenska textilföretag som idag har implementerat insamlingssystem, antingen internt eller via en tredjepartsorganisation. Det återanvändningsalternativ som används är främst återanvändning men till viss del även återvinning. Studien identifierar att ett problem som försvårar att stänga produktlivscykeln är att motivera konsumenten till att återlämna sina nyttjade plagg istället för att slänga dem. Textilföretagen ser även en svårighet med att få tillgång till teknik som möjliggör materialåtervinning. Ytterligare en aspekt som försvårar återvinningsprocessen är att textilbranschen idag ofta använder sig av heterogena material med fiberblandningar vilket gör det svårt att avgöra textiliernas materialinnehåll. Slutligen visar studien att avsaknaden av miljölagstiftning och direktiv inom textilbranschen leder till att det är svårt att definiera vad Closed-loop Supply Chain är, vilket försvårar hanteringen av textilavfall.