23. Quan hệ phản hồi

Nguyên tắc con

1. Introduce feedback
2. If feedback already exists, change its size or influence

Ví dụ

• A thermostat
• Auto-brightness that follows ambient light
• Cruise control holding a set speed

Ứng dụng theo lĩnh vực

• software: Recommendations keep missing what the user wants. What the user opens and what they skip is fed back into the recommendations.
• mechanical: As a tool wears, machined dimensions slowly drift. Measuring during machining corrects the tool position automatically.
• medical: Fixed insulin doses at fixed times leave blood sugar swinging. A pump linked to a continuous glucose sensor adjusts the dose on its own.
• electronics: A high-gain amplifier also distorts more. Feeding back a larger share of the output in opposite phase trades surplus gain for lower, more stable distortion.