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數位控制(二)
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Introduction to Discrete-Time Control System Digital Controller
Use of digital controller Decision-making capability Low cost digital computer Optimal performance
Plant: a physical object to be controlled. Furnace, Reactor, Servo system, spacecraft
Process: a series of gradual changes that succeed one another.
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Signals Continuous-time signal Sampled-data signal Digital signal Discrete-time signal
Sampling process Quantization A sequence of value at discrete time points Denoted by kT or tk (k = 0,1, 2,…) Sampling rate
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Signals
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Digital control system
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Data Acquisition and Data Distribution
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Transducer Amplifier
Amplify the voltage of the transducer Convert a current signal to a voltage signal A buffer
Low-pass filter: attenuate the high-frequency signal, such as noise signals.
Analog multiplexer De-multiplexer
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Analog multiplexer
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Sample-and-Hold (S/H)
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Analog-to-Digital Converter (ADC) Successive-
approximation type Integrating type Counter type Parallel type
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noise onQuantizati
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2
bitt significan Most :MSB
bitt significan Least :LSB
digits :n
range scale- Full:FSB
ErroronQuantizati
n
n
FSBLSB
FSBQ
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Offset error Linearity error Gain error
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Digital-to-Analog Converter (DAC) Weighted resistors
refo
o vbbb
bR
Rv )
842( 012
3
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R-2R ladder circuit
refnnno vbbbv )2
121
(21
0121
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hold Zero-order hold, First-order hold, Polygonal hold
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飛行器控制系統
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