---
title: "PID controller types and applications"
subject: "Embedded System"
chapter: 7
key: "semester_6/embedded_system:pid-types-realtime-application"
source: https://www.bctengineer.com/q/semester_6/embedded_system/pid-types-realtime-application
site: BCT Engineering
---

# PID controller types and applications

Embedded System · Chapter 7: Control System

- Asked in: 2076 Baisakh, 4 marks
- Video: [PID Controller Explained](https://www.youtube.com/watch?v=fv6dLTEvl74) — RealPars
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/embedded_system/pid-types-realtime-application
- Whole chapter: https://www.bctengineer.com/md/semester_6/embedded_system/chapter-7

## Question

What are PID controllers? Explain its types with real time application in embedded system.

## Short answer

PID controller computes u=Kp·e+Ki∫e dt+Kd·de/dt. P used where offset acceptable (toy car speed). PI used for accuracy in slow/noisy plants (temperature control, cruise control). PD used for fast damped response (robot arm, quadcopter attitude). PID used when accuracy, speed, damping all needed (motor drives, drone flight, 3D printer heater, CNC axis).

## Answer

A **PID controller** is a feedback controller that computes u = Kp·e + Ki·∫e dt + Kd·de/dt from the error e between the set-point and the measured value. Depending on which terms are used, it is a P, PI, PD or PID controller.

| Type | Use in embedded systems (real-time example) |
|---|---|
| P | Simple loops where a small offset is acceptable: a DC-motor speed loop in a toy car, simple water-level control. |
| PI | Where accuracy is needed and the plant is slow or noisy: temperature control of an oven or incubator, cruise control (speed held at the set value on slopes). |
| PD | Where a fast, damped response is needed: servo position of a robot arm or a camera gimbal, quadcopter attitude. |
| PID | Where accuracy, speed and damping are all needed: motor position/speed drives, drone flight controller, 3D-printer heater, CNC axis. |

Example (embedded): a microcontroller reads a temperature sensor with its ADC every 100 ms, computes the PID output and sets the PWM duty cycle of the heater. P reacts to the present error, I removes the final offset, and D prevents overshoot as the target is approached.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does a PID controller compute?
   A. u = Kp e only
   B. u = r - y
   C. u = Kp e + Ki integral(e) + Kd de/dt
   D. u = Kd e
   Answer: C. Sum of three terms. (Key point: PID definition)

2. Which application suits PD?
   A. Oven temperature
   B. Servo position of a robot arm or gimbal
   C. Simple toy motor
   D. Incubator
   Answer: B. Fast damped response. (Key point: PD use)

3. Which fits PI?
   A. Oven temperature or cruise control
   B. Quadcopter attitude
   C. Camera gimbal
   D. On/off control
   Answer: A. Accuracy, slow plant. (Key point: PI use)

4. In the heater example, what role does D play?
   A. Removes the final offset
   B. Reads the ADC
   C. Reacts to past error
   D. Prevents overshoot as the target is approached
   Answer: D. I removes offset, P reacts to present error. (Key point: Embedded example)

## Related in Embedded System

- [Define embedded system and its applications](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Adefine-embedded-system-applications) — Embedded System, chapter 1, asked 4×
- [Basic functions of real-time kernel](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Areal-time-kernel-functions) — Embedded System, chapter 6, asked 2×
- [Closed loop diagram; P, PI, PD, PID](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Aclosed-loop-block-diagram-pid-types) — Embedded System, chapter 7
- [Algorithm/pseudo-code for software PID](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Apid-software-algorithm) — Embedded System, chapter 7, asked 3×
- [Design metrics of embedded system](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Adesign-metrics-embedded) — Embedded System, chapter 1, asked 3×
- [Define embedded system and its characteristics](https://www.bctengineer.com/question.md?key=semester_6%2Fembedded_system%3Adefine-embedded-system-characteristics) — Embedded System, chapter 1, asked 2×

## Related in other subjects

- [Increasing reliability of embedded real-time software](https://www.bctengineer.com/question.md?key=semester_5%2Finstrumentation_ii%3Aembedded-rt-reliability) — Instrumentation II, chapter 9
- [Embedded real-time software; model for project](https://www.bctengineer.com/question.md?key=semester_5%2Finstrumentation_ii%3Aembedded-rt-software-model) — Instrumentation II, chapter 9
- [Use of PID controllers](https://www.bctengineer.com/question.md?key=semester_3%2Fcontrol_systems%3Apid-use) — Control Systems, chapter 7, asked 2×
- [When to prefer lag/lead or PID controllers](https://www.bctengineer.com/question.md?key=semester_6%2Fdigital_control_system%3Alag-lead-vs-pid) — Digital Control System, chapter 4