Giới thiệu về LabVIEW Thiết kế kiểm soát, Hệ thống nhận dạng và công cụ mô phỏng

Associate Professor (80% position) at Telemark University College and consultant viaTechTeach...
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Giới thiệu về LabVIEW Thiết kế kiểm soát, Hệ thống nhận dạng và công cụ mô phỏngPresentation by Finn Haugen at NI Days 2005 in Drammen, Norway, April 26 2005:Introduction to LabVIEW Control Design,System Identification and Simulation ToolsThis document and the linked files are available at http://techteach.no/presentations/. (The files may be updated at anytime.)Contents of this document1 Introduction1.1 A few words about my background1.2 Outline of the presentation1.3 The physical process - a DC motor1.4 The Compact FieldPoint I/O and embedded control system1.5 A procedure for analysis, design and implementation of a control system2 Black-box modelling of the process2.1 Introduction2.2 Exciting the process and measuring the response2.3 Estimating a mathematical model from logged data2.4 Is the model accurate? Comparing process simulation and measurements3 Control system analysis and design3.1 Analysis of control system using Control Design Toolkit3.2 Comparing simulated control system and real control system (target: PC)4 Implementing and testing the control system on the real-time target (CompactFieldPoint)1 Introduction1.1 A few words about my backgroundA few words about my background (http://techteach.no): • Teaching and writing and consulting in control engineering since about 1990 • Associate Professor (80% position) at Telemark University College and consultant via TechTeach • Developing KYBSIM (http://techteach.no/kybsim) - a library of freely available simulators developed in LabVIEW for dynamic systems, control and signal processing[Contents]1.2 Outline of the presentationThis presentation will demonstrate how to use the above toolkits in a practical application:Analysis, design, simulation and implementation of a speed control system for a DC motor usinga Compact FieldPoint system for I/O and embedded control. The motor and the CompactFieldPoint system are described briefly below.The following LabVIEW tools are used: • System Identification Toolkit Control Design Toolkit • Simulation Module •[Contents]1.3 The physical process - a DC motorIn this presentation a DC motor is modelled, simulated and controlled:DC motorThe motor is produced by Faulhaber. The control signal is in the range of ±10V, and thetachometer voltage is in the range of approximately ±10V. A load inertia has been added to themotor. The time constant of the motor including load and tachometer is approximately 0.3s. Aload torque can be applied to the motor by simply braking the motor (the load) by hand.[Contents]1.4 The Compact FieldPoint I/O and embedded control systemCompact Fieldpoint system used in this applicarion consists of the following modules: • cFP-2000 controller module running LabVIEW RT 7.1 • cFP-AIO-610 analog I/O moduleCompact FieldPointBelow is shown how the FieldPoint system appears in the Measurement and AutomationExplorer (MAX) utility.Measurement and Automation Explorer (MAX) showing the Compact FieldPoint system[Contents]1.5 A procedure for analysis, design and implementation of a control systemProcedure for analysis, design and implementation of a control systemIn the present application separate files implements the steps shown above. The logged data arestored in a spreadsheet file. The estimated model is also stored in a file.The figure below shows a block diagram of the process with controller and estimator, and blockscontaining functions for analysis and design of the control system.Block diagram of the process with controller and estimator, and blocks containing functions foranalysis and design of the control system.[Contents]2 Black-box modelling of the process2.1 IntroductionWhen a black-box model of a process is to be developed the process must be excited by asufficiently rich signal (we can of course not expect to derive a dynamics model from constantsignals). The excitation can be made in two ways, refer to the figure shown above): • Closed loop excitation. This means that the process is under feedback control. The excitation is via the setpoint. • Open loop excitation. This means that the process is not under feedback control. The excitation is via the control signal.In this application open loop excitation is used.[Contents]2.2 Exciting the process and measuring the responseexcite_and_logg.vi shown below saves time t, input signal u and measured response y on thespreadsheet file logfile1. t, u, and y are columns in this file. The sampling time is h = 0.02swhich is used both for analog output (control signal) and analog input (measurement signal)throughout this application.Front panel of excite_and_logg.viBlock diagram of excite_and_logg.viHere is the log file from one specific experiment: logfile1. The columns in the file are t, u, y.[Contents]2.3 Estimating a mathematical model from logged dataA mathematical model of the motor in the form of a discrete-time transfer function is estimatedusing the SI Estimate State Space Model function (which implements a Subspace-method whichis an efficient and generally applicable estimation method). This function is included in theSystem Identification Toolkit. The function palette of this toolkit is shown below. The SIEstimate State Space Model function is on the Parametric Modeling palette.Functions palette of System Identification Toolkitsystem_ident.vi shown below estimates a discrete-time transfer function model compatible withthe Control Design Toolkit, and saves the model on a file (or later use).Front panel of system_ident.viBlock diagram of system_ident.vi[Contents]2.4 Is the model accurate? Comparing process simulation and measurements[Introduction to Simulation Module]The functions palette of the Simulation Module is shown below.The functions palette of the Simulation ModuleIn compare_process_simulation_and ...