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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

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n

FSBLSB

FSBQ

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Offset error Linearity error Gain error

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Digital-to-Analog Converter (DAC) Weighted resistors

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R-2R ladder circuit

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hold Zero-order hold, First-order hold, Polygonal hold

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飛行器控制系統