Understanding Robotics: Sensors, Actuators, and Control Systems

Posted on Mar 2, 2025 in Technology

Robotics: Sensors, Controllers, and Actuators

A temperature controller-sensor measures the environment’s temperature. Based on this information, the driver activates or deactivates the actuator, which in this case is a radiator.

Sensor input → Driver → Actuator output

A control system is a group of elements that automates a process:

  • Entry: Gathers information.
  • Output: Responds to this information.

Types of Control Systems

Open Loop

Activated regardless of the output.

Closed Loop

Uses a sensor; the entry is not active without receiving information from the exit.

1. Sensors

Sensors act as the robot’s senses, gathering data from the outside environment. This data is sent to the control unit for processing to determine the appropriate action.

  • Temperature Sensor: Used in refrigerators and toasters.
  • Based on Dilatation: Composed of two plates that expand and bend when heated.
  • Position: Determines the position of an object.
    • Final Year
    • Reed
    • LDR (Light Dependent Resistor): Optical position, photodiodes
  • Pressure: Used in scales and tire pressure monitoring.
  • Moisture
  • Smoke
  • Sound

2. Actuators

Actuators transform control signals into force. They are classified according to the type of energy they require.

  • Electro: Transforms electrical energy into mechanical energy (DC and stepper motors).
  • Pneumatic: Converts energy from compressed air into movements.
  • Hydraulic: Uses the energy of a compressed fluid to generate energy.

Electromechanical Systems

  • Cam: Triggers outgoing contacts when they turn to control timing.
  • Limit Switch: Activates and deactivates devices.
  • Relay: Consists of a coil and a metal plate. When energy passes through the coil, it acts as a magnet, attracting the metal sheet.

Electronic Control

Uses transistors and control circuits.

  • Transistor
  • Comparators
  • Computer

Robot Structure and Function

A robot is a machine that operates automatically based on a program.

  • Structure: Equivalent to the human body.
  • Actuator: Muscles responsible for movement.
  • Sensor: Similar to senses.
  • Control Unit: Equivalent to the brain.

Robot Structure

  • Trunk
  • Arm
  • Forearm
  • Manipulator

Degrees of freedom of a robot are used to achieve any position for the executive action. The number of turns and independent movements, summing translations, determines the degrees of freedom.

Systems to Control Robots

  • Fixed Sequence Controls
  • Variable Sequence
  • Smart

Operating Systems

Operating systems are programs installed on a computer to control hardware and software. Examples include Windows, Linux, and macOS.

Programming Languages

  • Machine Language: The first language used, consisting of bit strings of zeroes and ones.
  • Assembly Language: Represented by mnemonic symbols.
  • High-Level Language (C++): Instructions are understandable for performing actions.
  • Natural Language: User-introduced instructions to the computer.

Process of Program Construction

Data Entry → Program → Instructions for Data Processing → Results → Output Stages

Phases:

  • Definition of the problem
  • Solution algorithm design: A set of rules that provide an answer to a problem, such as:
    • Pseudocode: Succession of phrases with a limited vocabulary and defined rules.
    • Flow Diagram: Using symbols.