electronics design laboratory lecture #6ecee.colorado.edu/ecen2270/lectures/lecture06.pdf · 2019....
TRANSCRIPT
![Page 1: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/1.jpg)
ECEN2270 1Electronics Design Laboratory
Electronics Design LaboratoryLecture #6
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Electronics Design Laboratory 2ECEN 2270
Speed Sensor and Filter
GND
5VDC
0-5V Speed Output proportional to actual motor speed
Vspeed
ForwardController
Reverse Controller
0-10V
0-10V
0-5V Speed Output proportional to desired motor speed
+-Speed error
Forward
NOT Forward
Experiment 1 & 2
Experiment 3A
Experiment 3B
Introduction to Lab 3 Part B: Closed-Loop Speed Control
ENCA
VDC+
VDC-
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DC motor driver and speed sensor
Electronics Design Laboratory 3
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
CI
vs
sense_PWM
Q1
Q3
Q2
Q4
vo
𝑓𝑒𝑛𝑐 =𝜔
2𝜋× 13 × 51 ≈ 106𝜔
( ) ( ) encon
enc
ons ft
t
tv V5V5 +=+=
ECEN2270
enctenct
R3 and C3 from speed sensor
![Page 4: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/4.jpg)
“Open-loop” speed control using vo
Electronics Design Laboratory 4
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
CI
vs
sense_PWM
Q1
Q3
Q2
Q4
vo
vo = +10V
Faster
Slower
ECEN2270
vo = 0
vs = 0
vs = +4V
![Page 5: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/5.jpg)
System Gains
Electronics Design Laboratory 5
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
CI
vs
sense_PWM
Q1
Q3
Q2
Q4
vo
𝑓𝑒𝑛𝑐 =𝜔
2𝜋× 13 × 51 ≈ 106𝜔
ECEN2270
enctenct
vrefμC
INPUT OUTPUT
![Page 6: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/6.jpg)
Speed sensor gain
Electronics Design Laboratory 6ECEN2270
Encoder OutputFrequency proportional to physical speed
encf
Speed Sensor PWMDuty cycle proportional to frequency
ont
𝑓𝑒𝑛𝑐 =𝜔
2𝜋× 13 × 51 ≈ 106𝜔Frequency of encoder pulses [Hz]
Speed sensor output voltage [V] 𝑣𝑠 = +5V𝑡𝑜𝑛𝑡𝑝
= +5V 𝑡𝑜𝑛𝑓𝑒𝑛𝑐
Speed sensor gain [Vs/rad] 𝐾𝑠𝑒𝑛𝑠𝑒 =𝑣𝑠𝜔= 106 × 5 × 𝑡𝑜𝑛 = 530 𝑡𝑜𝑛
5V
0V
Voltage OutputVoltage proportional to Duty Cycle
Physical Frequency Duty Cycle Voltage
Encoder Speed Sensor Low Passencf d
sv
![Page 7: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/7.jpg)
Open-loop system
Electronics Design Laboratory 7
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
CI
vs
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
vrefμC
INPUT OUTPUT
Speed sensor
senseK
enc
vs
![Page 8: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/8.jpg)
Closing the feedback loop: compensator
Electronics Design Laboratory 8
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
CI
vs
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
vrefμC
INPUT OUTPUT
Speed sensor
senseK
enc
vs
• Need vs to equal vref in steady state
• Need to change vo
depending on our speed error (vref - vs)
• Need 0-10V output and0-5V inputs.
![Page 9: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/9.jpg)
Integral compensator
Electronics Design Laboratory 9
+
_+10 V
O1
RI
RI
CI
CI
vs
vref
vo
( ) ( )sref
Isref
II
o vvs
Kvv
RsCv −=−=
1
ECEN2270
![Page 10: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/10.jpg)
Electronics Design Laboratory 10
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
Closed-Loop System with Integral Compensator
OUTPUT
Speed sensor
senseK
![Page 11: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/11.jpg)
Electronics Design Laboratory 11
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
Qualitative Analysis of Feedback Loop
OUTPUT
Speed sensor
senseK
sensed speed too high
vo goes down iDC goes down
goes down
fenc goes downvs goes down
![Page 12: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/12.jpg)
Electronics Design Laboratory 12
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
OUTPUT
Speed sensor
senseK
s
K I
)(sGm
Integral compensator
-+verror
vs
vrefμC
INPUT
Speed control circuit as a closed-loop system
![Page 13: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/13.jpg)
Speed control circuit as a closed-loop system
Electronics Design Laboratory 13ECEN2270
vref ve vo ω
vs
-+
m
o sG
+1
1
s
K I
)(sGc)(sGm
senseK
Integral compensatorDriver & motor
Speed sensor
Closed-loop response:
)(1
)(1)(
sT
sT
KvsG
senseref +==
Loop gain:
)()()( sGsGKsT mcsense=
![Page 14: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/14.jpg)
Closed-loop speed control
Electronics Design Laboratory 14
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
Steady-state:
vs = Ksense = vref
= vref/Ksense
End result: speed precisely set by vref, independent of load torque, motor imperfections, …
Faster
Slower
ECEN2270
![Page 15: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/15.jpg)
How to change direction?
Electronics Design Laboratory 15
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
ECEN2270
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Stop & Go Control
Electronics Design Laboratory 16ECEN2270
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
+5V
ON = GOOFF = STOP
![Page 17: Electronics Design Laboratory Lecture #6ecee.colorado.edu/ecen2270/lectures/Lecture06.pdf · 2019. 1. 24. · DC motor driver and speed sensor Electronics Design Laboratory 3 + 5V](https://reader035.vdocuments.us/reader035/viewer/2022070211/60fd7f187385883feb1eca4c/html5/thumbnails/17.jpg)
Stop & Go Control Implementation
Electronics Design Laboratory 17
S
DG
ECEN2270
+5Vencoder
DC1 DC2
iDC
VDCsupply
= +10 V
B1 B2
vDC+_
RBRB+
_+10 V
O1
O2
encspeed sensor(Lab 2)
+5V
tp = 1/fenctp = 1/fenc
ton
+5V +5V
00
RI
RI
CI
CI
vs
vref
sense_PWM
Q1
Q3
Q2
Q4
vo
+5V
PMOS
+5V = GO 0V = STOP
c
RG
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Speed Control Complete Schematic
Electronics Design Laboratory 18ECEN2270
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Feedback Control circuit block
• Op-amp integral compensator
• PMOS transistor used to force output vo at “b” low
• Two copies of the circuit used: one for each side of the motor (to control motor in each direction)
Electronics Design Laboratory 19
vo
ECEN2270
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Floor planning
Electronics Design Laboratory 20
GND
+10V
+5V
+5V GND
+5V
GND
+5V
GND
+10V
GND
+10V
GND
Left wheel Right wheel
Feedback circuits
Left wheel Right wheel
Arduino
Speed sensors
Space for project add-ons
Space for project add-ons
Project:Remote control
receiver
ECEN2270
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Speed Control Demo Setup
Electronics Design Laboratory 21
Use waveform generator, 0-5V, 500 Hz square wave, Hi-ZAdjust duty cycle to set the speed reference so that fenc = 200 Hz
Show speed-sensor output pulses on the scope. Frequency of the pulses should be fenc = 200 Hz
ECEN2270
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Soldering tips
Electronics Design Laboratory 22ECEN 2270