Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
vs.
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
H W G
VS VW
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Jeff Shelton β 24 February 2015
π π = π 1 + π 2 π 2 = π₯π π π 1 = 1 β π₯ π π π π
π 1 π 2
VS Vout +
β
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Jeff Shelton β 24 February 2015
OUT
ππππ =1
1 +π ππ πΏ
π₯ 1 β π₯ π₯ππ
Maximum nonlinearity occurs at: π₯ β2
3
Max nonlinearity: =400
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π π
π πΏ% f.s.d.
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Jeff Shelton β 24 February 2015
β’
β’
β’
β’
β’
β’
β’
β’
β’
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
Absolute Encoding
Incremental Encoding
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Jeff Shelton β 24 February 2015
Ch. 0
Ch. 1
Ch. 2
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Jeff Shelton β 24 February 2015
90β
Channel A
Channel B
Index
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Jeff Shelton β 24 February 2015
β’
β’
β’
Light Source
Moving Grate
Light Receiver
Collimated Beam
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Jeff Shelton β 24 February 2015
Channel A
Channel B
4X
2X
1X
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
Channel A
Channel B
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Jeff Shelton β 24 February 2015
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Rotary Encoder Linear Encoder
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Jeff Shelton β 24 February 2015
Target
Retro-reflector
Beam Splitter
Interferometer Receiver &
Signal Processing
Collimated
Laser Beam
Electrical Signal
Quadrature Output
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Jeff Shelton β 24 February 2015
ππ = πΎπΈππΉ β π = πΎπ β π
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
Time (sec)
Vel
oci
ty (
m/s
)
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
β’
β’
β’
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Jeff Shelton β 24 February 2015
Clear Output Latch
Reset Counter Set Timer
Start Timer Running
Read Counter (Load Output Latch)
Timer not done
Timer done
START
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Jeff Shelton β 24 February 2015
Timer not done and
no overflow
Timer done and no
overflow
Clear Output Latch
Reset Counter Set Timer
Start Timer
Read Counter (Load Output Latch)
Running
START
Set Output Latch to
Max Counter overflow
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
β’
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
πΈπ = sin ππ‘
ππ΄= πΈπ β sin π
ππΆ= πΈπ β cos π
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Jeff Shelton β 24 February 2015
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Jeff Shelton β 24 February 2015
β’
β’
ππ΄ = sin π β sin ππ‘
ππ΅ = cos π β sin ππ‘
Resolver
ππ = sin π β sin ππ‘
ππ = cos π + 120Β° β sin ππ‘
ππ = cos π β 120Β° β sin ππ‘
Synchro
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Jeff Shelton β 24 February 2015
ππ΄ = cos π β sin π β sin ππ‘ ππ΅ = sin π β cos π β sin ππ‘
sin π β π β sin ππ‘
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sin π β π
sin ππ‘
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Resolver Encoder
Cost Higher Lower
Implementation Complex Simple
Shock Resistance Rugged Limited
Inertia High Low
Weight Heavy Lighter
Output Analog Analog or Digital
Noise Immunity Sensitive Robust
Accuracy 4β40 arc minutes 0.25β6 arc minutes
Angle Measurement Absolute Absolute or Incremental
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