Frequency response и Bode plot - практическое понимание
Цель: Изучить тему «Frequency response и Bode plot - практическое понимание» 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
Frequency response показывает, как process changes amplitude and phase of sinusoidal disturbances at different frequencies. Bode plot contains magnitude ratio and phase versus frequency.
Intuition
Slow process filters high-frequency changes: rapid input oscillations hardly appear at output and phase lag grows. Dead time mainly adds phase lag. Excessive phase lag at frequency where loop gain high leads to instability.
Практическая работа
Without formulas, explain why large tank level cannot follow a valve oscillating every second, but can follow hour-long changes. Connect to low-pass nature.
Самопроверка
• Что показывает magnitude Bode?
• Что показывает phase?
• Как slow process treats high frequency?
• Что делает dead time with phase?
• Почему phase margin important?
Что нужно запомнить
- Frequency response показывает, как process changes amplitude and phase of sinusoidal disturbances at different frequencies.
- Bode plot contains magnitude ratio and phase versus frequency.
- Slow process filters high-frequency changes: rapid input oscillations hardly appear at output and phase lag grows.
- Excessive phase lag at frequency where loop gain high leads to instability.
- Without formulas, explain why large tank level cannot follow a valve oscillating every second, but can follow hour-long changes.