Robots rely on various sensors to perceive their internal state and external environment. Proprioceptive sensors measure the robot's internal conditions, while exteroceptive sensors gather data about its surroundings. These sensors work together to enable robots to navigate, interact, and make decisions.

Different sensor types have unique strengths and limitations. Proprioceptive sensors offer precise internal measurements but can drift over time. Exteroceptive sensors provide rich environmental data but may be affected by external conditions. Choosing the right sensors depends on the robot's specific application and operating environment.

Sensor Types in Robotics

Proprioceptive vs exteroceptive sensors

• Proprioceptive sensors measure internal state of the robot providing information about position, orientation, and movement enabling self-awareness and internal monitoring (encoders, IMUs)
• Exteroceptive sensors gather information about robot's environment detecting external objects, obstacles, and conditions facilitating interaction with surroundings and navigation (cameras, LiDAR)

Types of proprioceptive sensors

• Encoders measure rotational position and speed of motors or wheels using optical, magnetic, or mechanical methods providing feedback for precise motion control
• Inertial Measurement Units (IMUs) combine accelerometers and gyroscopes to measure linear acceleration and angular velocity used for orientation and motion tracking
• Potentiometers measure angular position of joints or linkages providing feedback for robotic arm control
• Force sensors measure applied forces on robot's components used in grippers for object manipulation

Types of exteroceptive sensors

• Cameras capture visual information of the environment for object recognition, visual navigation, and inspection (RGB, stereo, depth cameras)
• LiDAR uses laser pulses to measure distances creating 3D point clouds of the environment for mapping, localization, and obstacle detection
• Ultrasonic sensors emit sound waves to measure distances used for proximity detection and obstacle avoidance effective in short-range applications
• Infrared sensors detect heat signatures or measure distances for motion detection and temperature sensing
• GPS provides global position information used for outdoor navigation and localization

Comparison of sensor strengths

• Proprioceptive sensors
  • Strengths: high precision for internal state measurements, fast response times, not affected by environmental conditions
  • Limitations: accumulate errors over time (drift), limited information about external environment
• Exteroceptive sensors
  • Strengths: provide rich information about environment, enable complex interactions and decision-making, some types work well in various lighting conditions
  • Limitations: can be affected by environmental factors (lighting, weather), may require significant processing power, some types have limited range or resolution
• Scenario-specific comparisons
  • Indoor navigation: cameras and LiDAR excel in structured environments, ultrasonic sensors useful for close-range obstacle detection
  • Outdoor robotics: GPS provides global positioning, LiDAR effective for long-range sensing and mapping
  • Industrial robotics: encoders and force sensors crucial for precise manipulation, cameras useful for quality control and inspection tasks