Dead time и транспортное запаздывание
Цель: Изучить тему «Dead time и транспортное запаздывание» и закрепить её практическими заданиями и самопроверкой.
2 акад. часа чтение и разбор теории, решение задач, работа со схемой или виртуальным стендом и проверка понимания.
Основной материал
Dead time theta - delay between input change and observable output response. Example: chemical concentration changes at dosing point, analyzer located 100 m downstream. Fluid travel time creates pure delay.
Почему dead time опасен для control
Controller acts while not seeing result of previous action. Aggressive tuning may issue repeated corrections, which arrive later and cause oscillation. Ratio theta/tau is an important indicator of control difficulty.
Практическая работа
Flow velocity 1 m/s, analyzer 60 m downstream. Estimate transport delay. Discuss how moving analyzer closer changes controllability.
Самопроверка
• Что такое dead time?
• Чем он отличается от slow time constant?
• Почему delay destabilizes feedback?
• Как sensor location affects delay?
• Можно ли eliminate transport delay software-only?
Что нужно запомнить
- Dead time theta - delay between input change and observable output response.
- Example: chemical concentration changes at dosing point, analyzer located 100 m downstream.
- Controller acts while not seeing result of previous action.
- Aggressive tuning may issue repeated corrections, which arrive later and cause oscillation.
- Ratio theta/tau is an important indicator of control difficulty.