Which of the following is NOT a component of a robot axis?

The correct answer is the power supply, as it is not considered a direct component of a robot axis. Robot axes typically consist of components that directly contribute to the movement and positioning of the robot.

The servo motor is essential for providing the motion needed for the axis to function, allowing the robot to move with precision. The encoder plays a critical role in providing feedback on the position and speed of the servo motor, ensuring accurate control over the axis's movement. The home position sensor is important for establishing the robot’s starting or reference position, which is crucial for effective movement and operation.

In contrast, the power supply, while vital for the overall functioning of the robot, does not pertain specifically to the axis itself. Instead, it serves as a source of energy for all components, including motors and sensors, but does not function as a mechanical or control part of any single axis in the robot's structure.