Sensors provide the feedback necessary for the robot to understand its own state and interact with its environment. They are the robot's "senses."

Proprioceptive Sensors (Internal)

Monitor the internal state of the robot.

Joint Position Sensors:

Absolutely crucial for closed-loop control. Encoders (optical or magnetic) are the most common type, measuring the angular position of a motor shaft or joint with high precision.

Joint Velocity Sensors:

Can be derived by differentiating the position signal from an encoder, or measured directly using a tachometer.

Exteroceptive Sensors (External)

Gather information about the robot's environment.

Vision Systems 

Cameras (2D or 3D/depth) provide rich information for tasks like object recognition, inspection, and guidance.

Force/Torque Sensors 

Typically mounted at the robot's wrist, these sensors measure the forces and torques generated during interaction with an object. They are essential for tasks requiring delicate force control, such as assembly, grinding, or polishing.