Introduction to Robotics

• Robotics is a multidisciplinary field

Definition

• According to Larousse, a robot is an automatic device capable of manipulating objects or executing operations according to a fixed, modifiable, or adaptable program
• Another definition states that a robot is a polyarticulated mechanical system moved by actuators and controlled by a computer, designed to perform a wide variety of tasks
• A robot combines material components, like mechanics and hardware, with immaterial components, like software

Robotics Disciplines

• Mechanics
• Electronics
• IT
• Automation
• Materials Science
• Artificial intelligence
• Ethics
• Physics
• Mathematics

History

• 1947: The first remotely operated electric manipulator was created
• 1954: The first programmable robot was created
• 1961: The first industrial robot, Unimate, appeared on a General Motors assembly line
• 1963: The use of vision to control a robot was implemented

Robot Components

• Robots have four main components
• Articulated mechanical system (SMA)
• Terminal organ
• Sensors
• Controller
• Information processing system
• Actuators

Articulated Mechanical System (SMA)

• Robots have a mechanism with a structure similar to a human arm, that can replace or extend it
• The role is to bring the terminal organ into a given pose (position and orientation), according to speed and acceleration characteristics
• The architecture is a kinematic chain of bodies, generally rigid, connected by joints and powered by electric, pneumatic, or hydraulic actuators
• Movement is transmitted to the joints through appropriate systems like reducers

Sensors

• Sensors play a fundamental role in robotics because they allow robots to perceive their environment and interact with it autonomously or semi-autonomously
• Sensors work by detecting a variation (physical quantity) in their environment and converting it into an electrical or digital signal
• The signal can be interpreted by a processing system like a microcontroller or a processor

Common Robotic Sensors

• Distance sensors:
• LIDAR (Light Detection and Ranging): Emits a laser beam and measures the time it takes for the light to return after hitting an object to calculate the distance
• Ultrasonic sensors: Emit high-frequency sound waves and measure the time it takes for these waves to return after being reflected by an obstacle, then converts that time into distance
• Infrared sensors: Emit an infrared beam and detect the reflection of the beam by objects, using the intensity variation of the reflected signal to determine the presence of objects
• Light sensors: Measures the intensity of ambient light and can be employed to detect the brightness of the environment
• Temperature sensors: Measures the temperature of the environment and is utilized in applications like temperature monitoring, thermal regulation, and climate control
• Pressure sensors: Measures the force applied to a surface and is used in applications like force control and contact detection
• Motion sensors: Detect movements, inclinations, or rotations and are used for motion detection, stabilization, and orientation control
• Color sensors: Detect the colors of objects and are used in sorting applications as well as object identification
• Proximity sensors: Detect the presence of objects nearby without direct physical contact for obstacle detection
• Gas sensors: Detect the presence and concentration of gases in the environment and are used in applications like monitoring air quality
• Force sensors: Measures the force applied on a surface or object and is used in the manipulation of objects
• Humidity sensors: Measures the level of humidity in the air or in a material and is used in applications of humidity control
• Speed sensors: Measures the speed of the robot for speed control, fast motion detection, and trajectory tracking
• Vision sensors: Captures images and videos of the robot's environment like cameras and is essential for visual perception, object detection, and facial recognition

Actuators

• An actuator is a device used to convert an electrical, pneumatic, or hydraulic signal or command into a physical or mechanical action
• Actuators generate movements, forces, or physical actions in response to command signals and enable robots to interact actively with their environment by performing precise tasks
• Actuators are essential for object manipulation, movement, joint motion, and precision control

Actuators Used in Robotics

• Electric motors:
  • Generates rotations, translations, or precise movements.
  • DC Motors: Simple motors that use a continuous voltage to produce rotational movement, used in compact robots or small mobile devices
  • Stepper motors: These motors divide a complete turn into steps and are used when precision and movement control are crucial, offering angle of rotation control
  • Servomotors: Equipped with feedback system used to precisely control a movement's position, speed, and acceleration
  • Brushless motors: Compared to traditional brushed motors, these offer performance, longer life, and reduced maintenance, and are popular in high-performance robots
• Relays: Used to control powerful electrical circuits with weak electrical signals and functions as switches, with an electromagnetic coil that activates electrical contacts to close or open the circuit
• Pneumatic cylinders: Use compressed air to generate linear motion and are used to perform fast and powerful movements in robotics applications
• Hydraulic cylinders: Uses pressurized hydraulic fluid to generate motion and are used in applications that require strength