Figure list
Figure1. Illustrating the Analogy
Figure2. Schematic of the Coupled-Tank plant Figure3 The overall NetCon system Figure4 NetController
Figure5 Interface of NetConLink
Figure6 User Interface of NetConTop software Figure7 Coupled-tank Model Figure8 Coupled-tank Component Figure 9 Upper water tank level model
Figure 10 The open-loop transfer function of the upper water tank Figure 11 couple water tank level model
Figure 12 The open-loop transfer function of couple water tank Figure 13 Open-loop control system Figure 14 Close-loop control system
Figure 15 P-plus-feed forward close-loop control system Figure 16 Step response of a first order system- time constant Figure 17 PI-plus-feed forward close-loop control system Figure 18 Cascade and feedback control system Figure 19 The block of whole system Figure 20 Cascade system
Figure 21 The block diagram of Couple water tank water level PI-plus-feedforward
Control system
Figure 22The block diagram of Proportional controller Figure 23 The block diagram of Proportional integral controller Figure 24 The block diagram of Proportional controller Figure 25 The block diagram of couple water tank PI controller Figure 26 The system amplitude oscillation curve
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Figure27 couple water tank PI controller simulation results Figure 28 Digital-to-analog and analog-to-digital converter Figure 29 NetCon set Figure 30 NetCon set Figure 31 NetCon set Figure 32 NetCon set Figure 33 NetConTop set Figure 34 NetConTop set Figure 35 Calibration model Figure 36Calibration circuit board Figure 37 Saturation block Figure 38 Saturation set
Figure 39 Proportional control system block diagram Figure 40 P-plus-feedforward controller experiment result 1 Figure 41 P-plus-feedforward controller experiment result 2 Figure 42 PI-plus-feedforward control system block diagram Figure 43 PI-plus-feedforward controller experiment result 1 Figure 44 PI-plus-feedforward controller experiment result 2 Figure 45 PI-plus-feedforward controller experiment result 3 Figure 46 Cascade and feedback control system block diagram Figure 47 Cascade and feedback controller experiment result 1 Figure 48 Cascade and feedback controller experiment result 2 Figure 49 Cascade and feedback controller experiment result 3
Figure 50 Couple water tank PI-plus-feedforward control system block diagram. Figure 51 Couple water tank PI-plus-feedforward controller experiment result 1 Figure 52 Couple water tank PI-plus-feedforward controller experiment result 2 Figure 53 Couple water tank PI-plus-feedforward controller experiment result 3 Figure 54 Couple water tank PI-plus-feedforward controller experiment result 4
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Chapter1. Project Overview
1.1 Aim and Objectives:
The aim of the project:
The key aim of the project is to apply various control strategies to real-time level control of a water tank using computers.
The objectives of the project include:
a) Understand the level control problem of a water tank;
b) Study class and advance control methods, e.g., PID control, optimal control, adaptive control, fuzzy control, etc.
c) Be familiar with the following software: Matlab, Simulink, Real-Time Workship, NetCon System;
d) Simulate various control strategies (e.g., PI, PID control, optimal control, adaptive control, fuzzy control) in Simulink for closed-loop level control based on the model of a water tank;
e) Simulate various control strategies (e.g., PI, PID control, optimal control, adaptive control, fuzzy control) on the NetCon System for real-time close-loop level control, based on the model of a water tank;
f) Apply the simulated control strategies to a practical level control test rig.
1.2 General Background:
1.2.1 Single water-tank system
Now day in Inhabitant domestic water supply, beverages, food processing and other industries the production process, we usually need to use the water tank, it need to
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maintain the appropriate level, neither too overflow cause waste, also cannot too little and can't meet the demand.
A model of single water-tank is show as the figure one below. V1 is water drain valve. V2 is the inlet valve. The liquid level of the control requirement is h0. The water flow, which drain into the tank is controlled by V2 valve, water flow, which drains out of the tank, is controlled by V1 valve. The V1 open library is change with the needs of users. As a consequence to control the variable value of the water level h0 it is transfer to control the Water inflow. In is experiment to achieve control the inlet flow by using change the voltage which is driven the pump.
Figure1. Illustrating the Analogy
1.2.2 Couple water-tank system
Couple tank water is a typical model of nonlinear delay objects, much of the controlled object in industrial whole or partial can be abstracted as mathematics model of double water tank. It has strong representation and strong industrial background. In industrial production the mathematical modeling and control strategy of couple water tank has the guiding significance in research of liquid level control system. Such as industrial boilers, mold level control.
As is showed below the figure 2 is the couple water tank. The experiments require is control the bottom tank water level from the water flow coming out of the top tank.
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