In robotics, sensors are crucial components that provide robots with the ability to perceive their environment and their own internal state, enabling them to perform tasks effectively and safely. They act as the robot's "senses."
Understanding Robotic Sensors
Robotic sensors gather data from the world or from within the robot itself. This data is then processed by the robot's control system to make decisions and execute actions. Sensors can be broadly categorized into two main types based on what they measure: internal and external.
Internal Sensors
Internal sensors are those that measure the internal state of the robot. They provide information about the robot's own condition and movements.
Based on the reference provided:
- Internal sensors such as its position sensor, velocity sensor, acceleration sensors, motor torque sensor, etc. obtain information about the robot itself.
Examples of Internal Sensors:
- Position Sensors: Determine the angle or position of joints (e.g., encoders, potentiometers).
- Velocity Sensors: Measure the speed of movement (e.g., tachometers).
- Acceleration Sensors: Detect changes in speed and orientation (e.g., accelerometers, inertial measurement units - IMUs).
- Motor Torque Sensors: Measure the rotational force applied by motors.
These sensors are vital for controlling the robot's motion accurately and understanding its physical configuration at any given moment.
External Sensors
External sensors are used to gather information about the robot's surrounding environment. They help the robot perceive objects, distances, shapes, and other external factors.
Based on the reference provided:
- External sensors such as cameras, range sensors (IR sensor, laser range finder, and ultrasonic sensor), contact and proximity sensors (photodiode, IR detector...).
Examples of External Sensors:
- Cameras: Capture visual information (images or video) to recognize objects, navigate, or inspect.
- Range Sensors: Measure the distance to objects.
- IR Sensor: Uses infrared light to detect presence or measure short distances.
- Laser Range Finder: Uses a laser beam to measure distances, often over longer ranges with high accuracy.
- Ultrasonic Sensor: Emits sound waves and measures the time for the echo to return to determine distance.
- Contact and Proximity Sensors: Detect physical touch or the presence of an object nearby without contact.
- Contact Sensors: Respond to physical touch (e.g., touch switches).
- Proximity Sensors: Detect an object entering a specific area without physical contact (e.g., using infrared light, as with photodiodes and IR detectors, or other principles).
These sensors enable robots to interact with their environment, avoid obstacles, identify targets, and perform complex tasks that require awareness of the external world.
Key Differences
The fundamental distinction lies in what they measure: the robot's state versus the environment's state.
| Feature | Internal Sensors | External Sensors |
|---|---|---|
| Measures | Robot's own state (position, velocity) | Environment (objects, distances, features) |
| Purpose | Self-monitoring, precise motion control | Environmental perception, interaction, navigation |
| Examples | Encoders, Accelerometers, Torque Sensors | Cameras, Range Finders, Proximity Sensors |
In summary, internal sensors help a robot understand itself, while external sensors help it understand the world around it. Both types are essential for a robot to function autonomously and intelligently.
