JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV Year ROBOTICS Previous Question Paper (September - 2021 - R16)

The three degrees of freedom (DOF) provided to a robotic wrist are pitch, yaw, and roll. These movements allow the end-effector to achieve a specific orientation in 3D space regardless of the arm's position.

1. Pitch (Elevation): This is the rotation of the wrist in the vertical plane, often referred to as 'nodding' or 'up-and-down' movement. It changes the angle of the end-effector relative to the forearm.
2. Yaw (Azimuth): This is the rotation of the wrist in the horizontal plane, often referred to as 'side-to-side' movement. It allows the end-effector to sweep horizontally.
3. Roll (Twist): This is the rotation of the wrist about the longitudinal axis of the forearm. It allows the end-effector to rotate like a screwdriver, providing the final degree of freedom required for full spherical orientation.

Robotic manipulators are classified by their coordinate systems, which define the structure of the arm and the shape of the reachable workspace.

• Cartesian (Rectangular) Configuration: Consists of three sliding joints (prismatic) that move along the X, Y, and Z axes. The workspace is a rectangular box. It is highly accurate and rigid but requires a large floor space.
• Cylindrical Configuration: Features one rotary joint at the base and two prismatic joints. The workspace is a hollow cylinder. This configuration is well-suited for pick-and-place operations and machine loading.
• Spherical (Polar) Configuration: Uses one rotary joint at the base, one rotary joint for elevation, and one prismatic joint for reach. The workspace is a partial sphere. It offers a large reach but has more complex control requirements than Cartesian systems.
• Articulated (Jointed-Arm) Configuration: Resembles a human arm with three rotary joints (waist, shoulder, and elbow). The workspace is a complex, irregular volume. This is the most versatile configuration, capable of reaching around obstacles, and is widely used in welding and painting applications.