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Robotic Arms and Servo Motors

Sep 5, 2025

Overview

This lecture explains the mechanisms and components of robotic arms, focusing on servo motors, their functionality, benefits, and common applications in automation.

Introduction to Robotic Arms

  • Robotic arms are key to the automation revolution and mimic human arm movements.
  • Robots can be autonomous, semi-autonomous, or remote-controlled and excel at dirty, dull, or dangerous tasks.
  • Robotic arms are programmable manipulators, used in operations like welding and assembly.

Core Components of a Robotic Arm

  • Controllers act as the robot's brain, storing programs that govern its actions.
  • Arms consist of shoulder, elbow, and wrist joints, providing movement and flexibility.
  • End Effectors resemble fingers or claws, performing tasks like gripping and lifting objects.
  • Drives are motors located between joints, enabling controlled movement via belts.
  • Sensors detect surroundings and help avoid collisions, enhancing safety.

Servo Mechanics in Robotics

  • A servomechanism is a feedback-control system used to achieve precise motion.
  • Servo systems use multiple servomechanisms coordinated by a computer for complex, repetitive tasks.
  • Servos transform rotational motion to precise linear movement through motors, controllers, potentiometers, gears, and output splines.

Working Principle of Servo Motors

  • Motion controllers send pulse width modulation (PWM) signals to servos, determining rotation angle.
  • Potentiometers track position; servos hold their position until new commands are given.
  • Servos move proportionally fast or slow depending on the distance to the target position.

Advantages of Servo Motors in Robotic Arms

  • High-torque density enables fast, efficient movements vital for productivity.
  • Flexibility allows each joint to move independently, supporting diverse tasks and 6 degrees of motion.
  • High-precision control balances speed and accuracy, minimizing errors.
  • Programmability allows quick adaptation to new or changing tasks.
  • Durability ensures long life spans of up to 35,000 hours with proper maintenance.
  • Safety is enhanced through sensors that prevent accidents.

Types of Robotic Arms by Movement

  • Cartesian, SCARA, Articulated, Cylindrical, Delta, Polar, and Collaborative robots are common types, each with unique motion capabilities.

Applications of Robot Servo Motors

  • Robotics: Used in pick-and-place robots for precise object movement.
  • Conveyors: Enable accurate positioning and movement in assembly lines.
  • Cameras: Control lens position for automatic focusing.
  • Robotic Vehicles: Provide torque and speed control for movement in industrial and military vehicles.
  • Solar Tracking Systems: Adjust solar panel alignment for optimal energy capture.

Key Terms & Definitions

  • Robotic Arm — A programmable manipulator that performs tasks by mimicking a human arm.
  • Controller — The component storing and executing the robot's instructions.
  • End Effector — The tool or 'hand' at the end of a robotic arm.
  • Servo Motor — A motor providing precise control of angular or linear position.
  • Pulse Width Modulation (PWM) — A signal controlling servo motor rotation.
  • Potentiometer — A device measuring the position of the servo output.

Action Items / Next Steps

  • Review different types of robotic arms and their movement capabilities.
  • Study the working and programming of servo motors in more detail.
  • Explore real-world examples of robotic arm applications for better understanding.