Robotics & Robotic Control

What is a Robot?

• Intelligent device: motion controlled, planned, sensed.
• Electro-mechanical system.
• Performs tasks: cheaper, faster, more accurate/reliable than humans.
• Mimics human body parts (e.g., arms).

Degrees of Freedom

• Independent directions the end effector can move.
• Solid object max: 6 degrees of freedom.
• Translational: X, Y, Z.
• Rotational: Rx, Ry, Rz.
• Simple robots: 3 degrees of freedom.
• Modern arms: up to 7 degrees of freedom (XYZ, Roll, Pitch, Yaw).

Robotic Joints

• Rotary joints: waist, elbow.
• Linear/Prismatic joints: sliding joints.
• Used together for required movement (e.g., cylindrical robot).

Robot Geometry Considerations

• Cover large area.
• Perform intricate movements.
• Lift heavy loads.
• Move with high speed.
• Design for a specific job.

Axes of Motion

• Revolute joints: Allow rotations.
• Prismatic joints: Allow straight-line movement.
• More axes: more maneuverable, more complex programming.

Types of Robotic Arms

• Cartesian: X, Y, Z system.
• Cylindrical: (r, Z, θ).
• Polar: (r, θ, φ).
• SCARA.
• Anthropomorphic.

Robotic Work Envelopes

• Volume of space a robot can operate within.
• Size and shape vary.

Cartesian System

• Three translational directions (X, Y, Z).
• Movement at 90-degree angles.
• Best for large areas, not intricate movements.

Cylindrical System

• Rotation on central support.
• Three axes of motion (r, Z, θ).
• Faster movement than Cartesian.
• Two prismatic + one rotary joint.
• Applications: assembly, medical (DNA screening, drug development).

Spherical/Polar System

• Pivoted arm rotates in vertical plane.
• Covers surface of a sphere.
• Faster vertical movement than cylindrical.
• Restricted movement range.
• Applications: welding.

Anthropomorphic System

• Resembles human arm (Articulated/Revolute robot).
• Base rotates like human waist; revolute joints like human arms.
• Ideal for complex motions (spray painting, welding).

SCARA System

• Selective Compliant Assembly Robot Arm.
• Rotary joints rotate about vertical axes.
• Three degrees of freedom.
• Used for assembly operations.

Humanoid Robot

• Developed for recreation/entertainment.
• Research for household chores, elderly aid.

End Effectors

• Peripheral device attached to robot wrist.
• Grippers, tools, sensors.
• “End of Arm Tooling” (EOAT).

Common End Effectors

• Sensors: ultrasonic, laser, cameras, infrared.
• Grippers: Fingered (2-5 fingers), vacuum, magnetic, needle.

Mechanical Grippers

• Parallel.
• Angular.

Vacuum Grippers

• Suction cups for various materials and shapes.