Digital control is a branch of control theory that uses digital computers to act as system controllers. Depending on the requirements, a digital control system can take the form of a microcontroller to an ASIC to a standard desktop computer. Since a digital computer is a discrete system, the Laplace transform is replaced with the Z-transform. Also since a digital computer has finite precision (See quantization), extra care is needed to ensure the error in coefficients, A/D conversion, D/A conversion, etc. are not producing undesired or unplanned effects.
The application of digital control can readily be understood in the use of feedback. Since the creation of the first digital computer in the early 1940s the price of digital computers has dropped considerably, which has made them key pieces to control systems for several reasons:
- Inexpensive: under $5 for many microcontrollers
- Flexible: easy to configure and reconfigure through software
- Scalable: programs can scale to the limits of the memory or storage space without extra cost
- Adaptable: parameters of the program can change with time (See adaptive control)
- Static operation: digital computers are much less prone to environmental conditions than capacitors, inductors, etc.
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Famous quotes containing the word control:
“I have not ceased being fearful, but I have ceased to let fear control me. I have accepted fear as a part of life, specifically the fear of change, the fear of the unknown, and I have gone ahead despite the pounding in the heart that says: turn back, turn back, you’ll die if you venture too far.”
—Erica Jong, U.S. author. In an essay in The Writer on Her Work, ch. 13 (1980)