JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III FUNDAMENTALS OF ROBOTICS Previous Question Paper (August - 2022 - R16)

Robots can be classified based on several criteria to distinguish their capabilities, control methods, and applications:

• Based on Control Method: Servo-controlled robots use feedback loops to monitor position and velocity, allowing for precise motion. Non-servo robots operate on a fixed sequence of stops (pick-and-place) using mechanical stops.
• Based on Path Control: Point-to-point (PTP) robots move from one programmed point to another without controlling the path between them. Continuous path (CP) robots maintain a controlled velocity and trajectory throughout the entire movement.
• Based on Coordinate System: Robots are classified by their physical configuration, such as Cartesian (rectangular), Cylindrical, Spherical (Polar), or Articulated (Anthropomorphic) robots.
• Based on Programming Method: This includes manual lead-through (teaching by physical movement), powered lead-through (using a teach pendant), and off-line programming (using simulation software).
• Based on Intelligence Level: This ranges from simple fixed-sequence robots to intelligent robots equipped with sensors and AI to adapt to changing environments.

Sensors in robotics are categorized into internal sensors (measuring the robot's own state) and external sensors (measuring the environment). Common types include:

• Position Sensors: Measure the linear or angular position of joints.
• Velocity Sensors: Measure the speed of motion (e.g., tachometers).
• Force/Torque Sensors: Measure the interaction forces at the end-effector.
• Proximity and Range Sensors: Detect the presence or distance of objects (e.g., ultrasonic, infrared, or laser sensors).
• Vision Sensors: Use cameras for pattern recognition and object identification.

To measure the position of a gripper accurately, an Optical Encoder is the most suitable sensor. It is an electromechanical device that converts the angular position of a shaft into an analog or digital signal. An absolute encoder provides a unique digital code for every position, ensuring that the gripper's exact location is known immediately upon power-up without needing a homing sequence. For high-precision applications, incremental encoders are also used in conjunction with a reference index pulse to maintain high resolution and accuracy in tracking the gripper's movement.