What are sensors used in robotic mechanisms?

Short Answer:

Sensors used in robotic mechanisms are devices that detect physical quantities such as position, speed, temperature, distance, and pressure, and convert them into signals that robots can process. These sensors help robots interact with their surroundings and perform tasks accurately.

In robotic systems, sensors are mainly divided into internal and external types. Internal sensors measure robot’s internal states like joint angles or motor speed, while external sensors sense the environment such as objects, obstacles, or light. Together, they make robotic mechanisms more intelligent, precise, and adaptive.

Detailed Explanation :

Sensors Used in Robotic Mechanisms

Sensors are an essential part of any robotic mechanism because they provide the robot with information about itself and its surroundings. A robot cannot perform tasks correctly without knowing what is happening around it. Sensors act as the “eyes, ears, and touch” of the robot, converting physical phenomena into electrical signals that can be read and processed by its control system. These signals help the robot make decisions and perform tasks efficiently, just like human senses help people understand the environment.

In a robotic mechanism, sensors help achieve accuracy, safety, and automation. They provide feedback to control systems so that corrections can be made during motion. Depending on the type of information required, different sensors are used for different purposes such as detecting motion, position, distance, force, temperature, light, or sound.

Classification of Sensors

Sensors used in robotic mechanisms can be broadly classified into two main categories:

  1. Internal Sensors – These sensors measure the internal parameters of the robot such as joint position, angular velocity, or motor torque. They help in controlling motion and maintaining stability.
  2. External Sensors – These sensors measure external parameters such as distance from an object, temperature of surroundings, or light intensity. They allow robots to interact safely with the environment and adapt to changing conditions.

Common Types of Sensors Used in Robotic Mechanisms

  1. Position Sensors:
    Position sensors measure the position or movement of robot joints or links. Common types include potentiometers, encoders, and resolvers.

    • Potentiometers measure angular position by converting rotational movement into voltage changes.
    • Encoders (optical or magnetic) are highly accurate sensors that detect shaft rotation and convert it into digital pulses.
    • Resolvers are used for precise angular position measurement, especially in harsh environments.
  2. Velocity Sensors:
    These sensors measure the speed of rotating parts or moving links. The most common type is the tachometer, which produces a voltage proportional to speed. Encoders can also be used to calculate velocity by counting pulses over time.
  3. Force and Torque Sensors:
    Force sensors measure the amount of force applied by or on the robot. Torque sensors measure rotational force. These sensors are used in robotic arms to control grip strength and ensure delicate handling of objects. For example, in assembly robots, force sensors help detect whether an object is properly fitted.
  4. Proximity Sensors:
    Proximity sensors detect the presence or absence of an object near the robot without making contact. They are used for object detection, collision avoidance, and navigation.

    • Infrared sensors use light reflection to detect objects.
    • Ultrasonic sensors use sound waves to measure distance.
    • Capacitive and inductive sensors detect metallic and non-metallic objects based on electric and magnetic fields.
  5. Touch (Tactile) Sensors:
    These sensors detect contact between the robot and another object. They are often used in robot grippers to feel pressure or texture. Tactile sensors use small switches or pressure-sensitive materials to sense touch and send feedback to the control system for precise gripping.
  6. Temperature Sensors:
    These sensors measure heat levels in the robot or environment. Thermocouples and thermistors are commonly used to monitor motor temperature and prevent overheating in industrial robots.
  7. Vision Sensors:
    Vision sensors or camera systems allow robots to “see.” They capture images of the surroundings, and image processing software analyzes these images for tasks like object recognition, inspection, and navigation. Vision systems make robots more intelligent and autonomous.
  8. Sound Sensors:
    These sensors detect sound waves or vibrations. Microphones and ultrasonic receivers are used for communication and object detection based on echo patterns.
  9. Gyroscopic Sensors and Accelerometers:
    These sensors detect orientation, tilt, and acceleration. They help maintain balance and stability, especially in mobile robots or drones.
  10. Laser Range Finders and LIDAR Sensors:
    These sensors measure distance accurately by using laser beams. They are widely used in autonomous robots for mapping, navigation, and obstacle detection.

Functions and Applications of Sensors in Robots

Sensors play multiple roles in robotic mechanisms, such as:

  • Feedback control: Sensors continuously monitor motion and send feedback to controllers for precise positioning.
  • Environment detection: Robots use sensors to identify objects, obstacles, and surfaces for safe navigation.
  • Safety and protection: Temperature and proximity sensors prevent collisions and overheating.
  • Automation and decision-making: Vision and force sensors provide data for intelligent actions and self-correction.

In industrial robots, sensors are used for assembly, welding, material handling, and inspection tasks. In medical and service robots, sensors ensure precision, comfort, and safety. For example, surgical robots use force and vision sensors to perform delicate operations with high accuracy.

Conclusion

Sensors used in robotic mechanisms are vital for making robots intelligent, responsive, and efficient. They help robots sense both their internal condition and external environment, allowing accurate control and safe operation. With advancements in sensor technology, modern robots are becoming more precise and capable of performing complex tasks with minimal human supervision. Thus, sensors are the key elements that transform mechanical robots into smart and autonomous systems.