Robot sensors can be categorized into internal sensors and external sensors based on the type of object being detected.
Internal sensors are mainly used to detect the robot's own state (such as the angle between the arms), and are mostly sensors that detect position and angle.
External sensors are primarily used to detect the robot's environment (such as what objects are present and how far away they are) and their status (such as whether the grasped object has slipped). Specific types include object recognition sensors, object flaw detection sensors, proximity sensors, distance sensors, force sensors, and auditory sensors.
1. Two-dimensional vision sensor
A two-dimensional vision sensor is essentially a camera that can detect and locate the movement of objects. Two-dimensional vision sensors have been around for a long time, and many smart cameras can work together to coordinate the movement of industrial robots and adjust the robot's behavior based on the received information.
2. Three-dimensional vision sensor
Recently, 3D vision sensors have been gaining popularity. A 3D vision system requires two cameras to capture images from different angles, allowing the 3D model of an object to be detected and recognized. Compared to 2D vision systems, 3D sensors can display objects more intuitively.
3. Force and torque sensor
Force and torque sensors are sensors that allow robots to sense forces. They can monitor the forces on a robot arm and, based on data analysis, guide the robot's subsequent actions.
4. Collision detection sensor
The most critical requirement for industrial robots, especially collaborative robots, is safety. To create a safe working environment, robots must be able to recognize what is unsafe. The use of a collision sensor allows a robot to understand what it has bumped into and send a signal to pause or stop its movement.
5. Safety sensors
Unlike the collision detection sensors mentioned above, safety sensors allow industrial robots to sense the presence of objects in their surroundings, thus preventing collisions between the robot and other objects.
6. Electromagnetic sensors
Modern magnetic rotary sensors mainly include four-phase sensors and single-phase sensors. During operation, a four-phase differential rotary sensor uses one pair of detection units for differential detection and another pair for inverse differential detection. Thus, the detection capability of a four-phase sensor is four times that of a single-element sensor. Two-element single-phase rotary sensors also have their advantages, namely compact size, reliability, large output signal, ability to detect low-speed motion, strong resistance to environmental influences and noise, and low cost. Therefore, single-phase sensors will also have a good market.
7. Fiber optic sensor
Fiber optic sensors are a relatively new technology that has emerged in recent years. They can be used to measure a variety of physical quantities, such as sound fields, electric fields, pressure, temperature, angular velocity, and acceleration, and can also perform measurement tasks that are difficult to accomplish with existing technologies. Fiber optic sensors have demonstrated unique capabilities in confined spaces, environments with strong electromagnetic interference, and high voltage. Currently, there are more than 70 types of fiber optic sensors, broadly categorized into sensors that utilize the fiber itself and sensors that utilize optical fibers.
8. Bionic sensors
Bionic sensors are a new type of sensor that employs novel detection principles. They combine immobilized cells, enzymes, or other bioactive substances with a transducer to form the sensor. This type of sensor represents a new information technology that has developed in recent years through the interdisciplinary integration of biomedicine, electronics, and engineering. These sensors are characterized by high performance and long lifespan. Among bionic sensors, those that mimic biological organisms are commonly used.
9. Infrared sensor
The core of an infrared system is the infrared detector, which can be broadly classified into two categories based on its detection mechanism: thermal detectors and photon detectors. Thermal detectors utilize the radiative thermal effect; when the detection element receives radiant energy, its temperature rises, causing changes in the detector's temperature-dependent properties. Detecting these changes in a specific property allows for the detection of radiation. In most cases, radiation is detected through thermoelectric changes. When the element receives radiation, causing a non-electrical physical change, the corresponding electrical change can be measured after appropriate transformation.
10. Pressure sensor
Piezoelectric sensors are primarily used in the measurement of acceleration, pressure, and force. A piezoelectric accelerometer is a commonly used type of accelerometer. It boasts excellent characteristics such as simple structure, small size, light weight, and long service life. Piezoelectric accelerometers have been widely used in vibration and shock measurements in aircraft, automobiles, ships, bridges, and buildings. Their unique shape gives them a special place in the aerospace field.
