Implementation of a Temperature Control System using ARDUINO · Phase control TCA 785 Control...
Transcript of Implementation of a Temperature Control System using ARDUINO · Phase control TCA 785 Control...
Fuzzy Logic Systems G. Oltean
Implementation of a Temperature Control
System using
ARDUINO
Fuzzy Logic Systems G. Oltean
Close control loop
Fuzzy controller
Fuzzy logic system: 9 rules
Temperature Sensor
One Wire Digital Temperature Sensor - DS18B20
Heating element
Heating resistor 2Ω, supplied in ac (12V peak value)
Heating power control
Phase control of a SCR (thyristor) – TCA 785
System structure
Fuzzy Logic Systems G. Oltean
Arduino development board
• “Brain” of the entire system
• Read current temperature
• Compute error and change-of-error
• Run fuzzy logic system
• Determine digital value of control signal
DAC - MCP4725, I2C interface
Provide analog value of control signal
Phase control board
Analog amplifier for control voltage – AD820
TCA 785 – phase control IC
System implementation
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Block diagram
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Functional diagram u(k) = u(k-1) - duc(k)
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ARDUINO UNO development board
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Programmable Resolution 1-Wire Digital Temperature Sensor
9-bit to 12-bit Celsius temperature measurements
Unique 1-Wire® Interface Requires Only One Port Pin for
Communication
Allows multiple DS18B20s to function on the same 1-Wire bus
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12-Bit Resolution
On-Board Non-Volatile Memory (EEPROM)
External Voltage Reference (VDD)
Rail-to-Rail Output
Single-Supply Operation: 2.7V to 5.5V
I2C Interface
Eight Available Addresses
DAC MCP4725
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Phase control TCA 785
Control thyristors, triacs, and transistors.
The trigger pulses can be shifted within a
phase angle between 0 ˚ and 180 ˚
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TCA 785
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Thermal enclosure Phase control board
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16 x 2 LCD
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Experimental setup
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Experimental setup
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Fuzzy logic system
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-1 -0.5 0 0.5 10
0.2
0.4
0.6
0.8
1
err; cerr
Neg
Zero
Pos
-1 -0.5 0 0.5 10
0.2
0.4
0.6
0.8
1
du
N
Z
P
Input fuzzy sets
Output fuzzy sets
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Control surface
errFls
cerrFlsNeg Zero Pos
Neg N N Z
Zero N Z P
Pos Z P P
Rule base
1
2
3
4
5
6
7
8
9
Fuzzy Logic Systems G. Oltean
Waveforms
for the
phase
control
circuit
CH3 - the analog control voltage applied at pin 11 of the TCA785 IC, 4.8V
CH2 - the ramp voltage, generated by the TCA785 IC, at pin 10
CH1 - the positive voltage pulse generated by the TCA785 at pin 15, to be applied in the gate of the
SCR to set it on (ch1, yellow); the voltage pulse is generated when the ramp voltage exceeds the
analog control voltage
CH4 - the almost sinusoidal supply voltage, in the secondary of the line transformer; the moment
when the SCR switches on (when the positive pulse appears in its gate) is obvious on the waveform –
the voltage decreases due to the large current ensured through the 2Ω heating resistor
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9 Waveforms
for the
power
circuit
CH1 - the supply voltage, in the secondary of the line transformer
CH2 - the voltage drop across the SCR
MATH - the voltage drop across the heating resistor
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0 500 1000 1500 2000 250025
30
35
40
45
50
time [s]
tem
pera
ture
[C
]
Tref
T
Experimental results, Tref = 45oC
process perturbation:
opening the thermal enclosure
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0 500 1000 1500 2000 250020
40
60
tem
p
0 500 1000 1500 2000 2500-20
0
20
err
0 500 1000 1500 2000 2500-20
0
20
cerr
0 500 1000 1500 2000 2500-1000
0
1000
du
0 500 1000 1500 2000 25000
2000
4000
u
Experimental results, Tref = 45oC
Fuzzy Logic Systems G. Oltean
0 500 1000 1500 2000 250020
40
60te
mp
0 500 1000 1500 2000 2500-1000
0
1000
du
0 500 1000 1500 2000 25000
2000
4000
u
0 500 1000 1500 2000 25000
2
4
con
tr.
vo
ltag
e
Experimental results, Tref = 45oC
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Experimental results, Tref = 37oC
0 100 200 300 400 500 600 700 800 90026
28
30
32
34
36
38
time [s]
tem
pera
ture
[C
]
Tref
T
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Experimental results, Tref = 34oC from 37oC
0 200 400 600 800 1000 120033.5
34
34.5
35
35.5
36
36.5
37
time [s]
tem
pera
ture
[C
]
Tref
T
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0 200 400 600 800 1000 120030
35
40te
mp
0 200 400 600 800 1000 1200-1000
0
1000
du
0 200 400 600 800 1000 12002000
4000
6000
u
0 200 400 600 800 1000 12002
3
4
con
tr.
vo
ltag
e
Experimental results, Tref = 34oC from 37oC