Sensors

Getting the world into numbers.

Common types

Encoders measure joint position, cameras give rich but ambiguous images, lidar measures distance directly, and force sensors detect contact. Each has a failure mode.

Every sensor is noisy, and filtering is part of the design rather than an afterthought.
Sensor fusion combines several imperfect sources into a better estimate.

Perception

Turning raw readings into a useful description of the scene is the hard part. A camera gives pixels; knowing that a mug is present, upright and graspable is another problem entirely.