Parts and Functions of a Robot - JSS 2 Note

PARTS AND FUNCTIONS OF A ROBOT

Subject: Digital Technologies

Class: JSS 2

Term: Third Term

Week: 2

Topic: Parts and Functions of a Robot

Duration: 80 Minutes (Double Period)

Learning Objectives

By the end of the lesson, students should be able to:

1. Identify sensors, actuators and controllers.
2. Explain the functions of sensors, actuators and controllers.
3. Explain the role of software in robotics.

1. Parts of a Robot

In the last lesson, we learnt that a robot is made up of a body or frame, a power supply, sensors, a controller and actuators. In this lesson, we study the sensors, actuators and controllers in more detail, and we learn about the role of software in robotics.

Sensor  -->  Controller  -->  Actuator
(detects)    (decides)        (acts)
               ^
               |
           Software (instructions)

2. Sensors

Sensors are devices that detect information from a robot's surroundings and send it to the controller.

Sensors work like the senses of a human being. They allow a robot to "see", "hear" or "feel" what is around it.

Sensor	What It Detects	Example of Use
Touch sensor	Contact or pressure.	A robot stops when it bumps into a wall.
Light sensor	Brightness of light.	A robot follows a bright or dark line.
Distance sensor	How far away an object is.	A robot vacuum avoids furniture.
Sound sensor	Sound or voice.	A robot responds to a clap or a spoken command.
Temperature sensor	Heat or cold.	A robot monitors the temperature of a machine.
Camera	Images and video.	A robot recognises objects or faces.

3. Actuators

Actuators are the parts of a robot that produce movement or action when they receive instructions from the controller.

Actuators work like the muscles of a human being. They turn the controller's instructions into real action.

Actuator	Function	Example of Use
Motor	Turns wheels or other parts.	Moves a robot forward, backward or in a circle.
Servo motor	Moves a part to an exact position or angle.	Raises or lowers a robotic arm.
Gripper	Opens and closes to hold objects.	Picks up and places items on a production line.
Speaker	Produces sound.	A robot speaks or sounds an alarm.
Light (LED) or display	Shows signals or messages.	A robot lights up to show that it is working.

4. Controllers

The controller is the part of a robot that receives information from the sensors, processes it, makes decisions and sends instructions to the actuators. It is often called the "brain" of the robot.

Common controllers include microcontrollers and small computers, such as Arduino and Raspberry Pi boards.

Functions of the Controller

1. It receives information from the sensors.
2. It processes the information according to a program.
3. It makes decisions about what the robot should do.
4. It sends instructions to the actuators.

5. Role of Software in Robotics

Software is the set of instructions (programs) that tells the controller what to do and how to respond to the information it receives.

The hardware parts of a robot cannot work properly without software. The sensors, controller and actuators are only physical parts. Software gives the robot its behaviour.

The Roles of Software

1. Gives instructions: It tells the robot what tasks to perform.
2. Controls decisions: It uses conditions to decide what the robot should do in different situations.
3. Controls movement: It tells the actuators when to start, how fast to move and when to stop.
4. Processes sensor data: It helps the controller understand the information from the sensors.
5. Allows changes: The robot's behaviour can be changed by changing the program, without changing its body.

Example

The following instructions show how software can control a robot using a distance sensor, just like the conditions and loops used in Scratch:

Repeat forever
  If distance sensor detects an object close ahead
     Stop the motors
     Turn right
  Else
     Move forward

6. How the Parts Work Together

Consider a robot vacuum cleaner that must avoid hitting furniture:

Part	What It Does in the Robot Vacuum
Sensor	The distance sensor detects a chair in front of the robot.
Software	The program says, "If an object is close, stop and turn."
Controller	Processes the sensor information, follows the program and decides to turn.
Actuator	The motors stop the wheels and turn the robot in a new direction.

Note: A robot works well only when all its parts work together. Sensors without a controller cannot make decisions, and a controller without actuators cannot move or act.

7. Class Activity: Sensor, Controller or Actuator?

Objective: Students will identify sensors, actuators and controllers and explain their functions.

Activity A: Classify the Parts

Copy the table below and tick the correct column for each part.

Part	Sensor	Controller	Actuator
Camera
Servo motor
Microcontroller
Touch sensor
Gripper

Activity B: Trace the Robot's Action

A robot is moving across a room when it detects a wall in front of it. It stops and turns left.

• Which part detected the wall?
• Which part decided that the robot should stop and turn?
• Which parts carried out the stopping and turning?
• What role did the software play?

8. Summary

• Sensors detect information from the robot's surroundings.
• Actuators produce the movement or action of the robot.
• The controller receives information, processes it and sends instructions to the actuators. It is the brain of the robot.
• Software is the set of instructions that tells the controller what to do.
• Sensors, controller, actuators and software work together to make a robot function.

9. Evaluation Questions

1. What is a sensor?
2. List four types of sensors and state what each detects.
3. What is an actuator? Give two examples.
4. Why is the controller called the brain of a robot?
5. State three functions of a controller.
6. What is software in robotics?
7. State three roles of software in a robot.
8. How do sensors, the controller and actuators work together?

10. Assignment

1. Define sensors, actuators and controllers.
2. Describe four types of sensors and state what each detects.
3. Describe three types of actuators and state what each does.
4. Explain the functions of a controller in a robot.
5. Explain the role of software in robotics.

11. Interactive Revision Quiz

Select one answer for each question and click Mark Quiz to see your score.

1. Which part of a robot detects information from its surroundings?

Actuator Sensor Controller Frame

2. Which sensor measures how far away an object is?

Light sensor Sound sensor Distance sensor Touch sensor

3. Which sensor detects brightness?

Light sensor Touch sensor Temperature sensor Gripper

4. Which of the following is an actuator?

Camera Distance sensor Microphone Motor

5. What does the controller of a robot do?

It only supplies power It processes information and sends instructions It gives the robot its colour It only stores pictures

6. Which of the following is an example of a controller?

Microcontroller Wheel Touch sensor Gripper

7. What is software in robotics?

The body of the robot The battery of the robot A set of instructions that tells the controller what to do The wheels of the robot

8. A robot stops when its distance sensor detects a wall. Which part decides to stop?

The sensor only The wheel The controller, following the program The battery

9. What would happen to a robot's controller without software?

It would work faster It would not know what to do It would become a sensor It would charge the battery

10. Which is the correct order in which a robot reacts to its surroundings?

Sensor, controller, actuator Actuator, sensor, controller Controller, sensor, actuator Actuator, controller, sensor