Unformatted text preview: t
Time If K=35, oscillation frequency is obtained by the
auxiliary equation 2008/09 MECH466 : Automatic Control Exercises
Read Sections 6.1-6.4.
6.1Solve Problems 6.12,13,14,20,21,22.
23 2008/09 MECH466 : Automatic Control 24 6 Announcements How to write a lab report Lab #2 starts next week. If you miss the regular
session of Lab 2 exercise, please finish it by
February 13 (one day after the midterm). (We
need to remove the water column setup soon
Lab #1 reports (per group) must be handed in to
TAs at the beginning of your Lab #2 session.
Late hand-in will NOT be accepted! (Without
Late hand- As part of your formal write-up, for each
Tables and graphs
Answers to the questions
Analysis of your results
Conclusions handing in the report in time, you lose 2.5 %
2008/09 MECH466 : Automatic Control 25 2008/09 Inlet
Valve A Inlet
Valve B Requirement: Tank A Tank B
Unit Valve AB
Transducer A Pressure
Valve A Disturbance
Valve Maintain the level of
Tank B at a desired
level by controlling
the flow through
control valve. Desired level
Modeldesign (Actuator) Controller
(Lab #2) Control
valve Flow (Plant) Tank level
(inch) Tank B Sensor
(Lab #1) Process
Valve B Sensed
level Pump MECH466 : Automatic Control Voltage Pressure Actual
level Calibration! Figure 1. Schematic of the Tank Level Control Setup. 2008/09 26 Water tank level control
Block diagram Water tank level control (Lab 2)
valve MECH466 : Automatic Control 27 2008/09 MECH466 : Automatic Control 28 7 On-off (bang-bang) control
(Valve fully open) (Valve fully closed) On-off control (cont’d) “On”
On” Simplest control
No parameters to be chosen
Difficult to maintain the level at the desired level.
Small difference between high and low limits
causes the chattering (rapid switching) problem.
Over-reaction (Small change of water level may
Overcause full action of valve.) This can be avoided
by a proportional control. High limit
Low limit High limit
2008/09 MECH466 : Automatic Control 29 2008/09 Proportional control (P-control) MECH466 : Automatic Control 30 Prelab for Lab 2
Before going to Lab 2, think about how to complete
the blank part for both on-off and P-control!
onP- Set value (desired level)
Controller gain KP (design parameter)
Command voltage (See Slide 26 for notation)
Command Note that there is a steady state error.
Set value 2008/09 MECH466 : Automatic Control 31 2008/09 MECH466 : Automatic Control 32 8 Some useful LabVIEW blocks
(TRUE or FALSE) If “s”=TRUE,
then the output is “t”.
then the output is “f”.
2008/09 MECH466 : Automatic Control 33 9...
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This document was uploaded on 03/05/2014 for the course MECH 466 at UBC.
- Winter '09