Lesson Notes By Weeks and Term v4 - SHS 1
Robot Control Principles
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Robot Control Principles
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Subject: Robotics
Class: SHS 1
Term: 1st Term
Week: 5
Grade code: 1.1.2.LI.2
Strand code: 1
Sub-strand code: 2
Content standard code: 1.1.2.CS.1
Indicator code: 1.1.2.LI.2
Theme: Principles of Robotic Systems
Subtheme: Robot Control Principles
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Welcome, future engineers and innovators! Today, we are going to look inside a robot's "body" to understand how it works. Think about your own body. Your eyes see, your brain thinks, and your hands move. You don't think about how they work together; it just happens. A robot is similar. It has different parts that work together to perform a task. Understanding these parts, called subsystems, is the first and most important step to learning how to control a robot. In Ghana, robots are no longer just science fiction.
What is a Subsystem? A subsystem is a complete system that works as a part of a larger system. In a robot, each subsystem has a specific job. For the robot to work, all its subsystems must work together perfectly. The five main subsystems we will focus on are: The Control System (The "Brain") Sensors (The "Senses") Actuators (The "Muscles") Power System (The "Heart") Mechanical Structure (The "Skeleton")
Let's break them down. The Control System (The "Brain") Description: This is the central processing unit of the robot. It is usually a microcontroller (like an Arduino or a Raspberry Pi) or a computer. It runs the program or instructions we give it. Function: Receives information from the sensors. Processes this information based on its programming. Makes decisions. Sends commands to the actuators to make the robot do something. Analogy: It's like your brain. Your brain gets information from your eyes and ears, thinks about what to do, and then tells your muscles to move. Sensors (The "Senses") Description: These are the parts of the robot that collect information from the outside world (the environment). They are the robot's eyes, ears, and sense of touch. Function: To detect things like light, sound, distance, touch, and temperature and convert that information into an electrical signal that the control system can understand. Examples relevant to us: Ultrasonic Sensor: Measures distance using sound waves, like a bat. A robot car uses this to avoid bumping into the wall. Light Sensor (LDR - Light Dependent Resistor): Detects the level of light. An automated street light robot would use this to know when it's dark enough to turn on. Touch/Bumper Sensor: A simple switch that detects when the robot has physically touched something. Infrared (IR) Sensor: Can be used to detect obstacles or to follow a black line on a white surface. Actuators (The "Muscles") Description: These are the parts of the robot that create movement or action. They are the robot's muscles. Function: To convert electrical energy into physical motion. They receive commands from the control system and execute them. Examples: DC Motors: Spin continuously. Used for the wheels of a mobile robot. Servo Motors: Can rotate to a specific angle and hold that position. Used for robot arms, steering systems, or a robotic gripper. LEDs (Light Emitting Diodes): A simple actuator that produces light. Buzzer: An actuator that produces sound. Power System (The "Heart") Description: This subsystem provides the electrical energy that all the other parts of the robot need to function. Function: To store and supply electricity to the controller, sensors, and actuators. Examples: Batteries (Alkaline, Li-Po), a direct connection to a wall socket via a transformer. Without power, the robot is just a piece of metal and plastic. Mechanical Structure (The "Skeleton") Description: This is the physical frame and body of the robot. It holds everything together. Function: To provide support, shape, and protection for all the other components. It also includes the parts that interact with the world, like wheels, legs, and grippers. Examples: The chassis of a robot car, the arm of an industrial robot, the frame of a drone. How They Interconnect: A Step-by-Step Example
Let's imagine a simple robot whose job is to move forward until it gets close to a wall, and then stop. Scenario: An Arduino-based robot car. Goal: Avoid crashing into a wall.
Here is the flow of information and action: POWER: The Power System (a battery pack) is on, supplying electricity to everything. SENSING: The Ultrasonic Sensor (a *Sensor*) continuously sends out sound waves and measures how long they take to bounce back. It calculates the distance to the wall. COMMUNICATION (Sensor to Controller): The sensor converts this distance into an electrical signal and sends it to the Control System (the Arduino board). PROCESSING (The "Thinking"): The Arduino reads the signal. Its program has an instruction like: `IF distance Brain (Controller) -> Hand (Actuator) Robot: Touch Sensor -> Arduino -> Motor Provide a worksheet with two columns: one with subsystem names and one with their functions. Learners will draw lines to match them. Work in a small group with the physical robot. Point to each part (wheel, sensor, board) and have learners name the subsystem it belongs to. Extension (For High-Achieving Learners) Task: Research the subsystems of a complex, real-world robot like the Boston Dynamics' Spot robot dog or a deep-sea remotely operated vehicle (ROV). Activity: Create a detailed presentation or report that goes beyond the five basic subsystems. They should identify specific types of sensors (e.g., LiDAR, IMUs), actuators (e.g., hydraulic vs. electric), and discuss additional subsystems like the Communication System (how it sends data back to humans) and the Software/Programming that acts as the "intelligence" within the control system. They can present their findings to the class.