The term ‘sensor’ is used to describe any type of device capable of detecting, measuring and/or recording a physical property, and then responding to it. By equipping robotic devices with sensors, robotics have become increasingly capable of performing a multitude of complex and sophisticated tasks for various industrial purposes.
In fact, large companies such as Google, Honda and Boston Dynamics have invested large sums of money to further improve sensor technology for its future implementation in robotics that are capable of better recognizing their environment and other surroundings.
Types of Robotic Sensors
When making the choice on what sensor is best for a given robotic, the specific actions that will be performed by the robot must first be considered. Since robots are typically designed to perform a multitude of different tasks, they are often equipped with a variety of different types of sensors that work together. Some of the different types of sensors, as well as their characteristics, that can be found in robotics are listed below.
The use of light sensors in robotics is particularly useful to assist with navigation and object detection by detecting light that reflects off of surrounding objects and measuring its distance from the robot. As both easy to install and inexpensive sensors, the two most commonly used light sensors in robotics include photoresistor and photovoltaic (PV) cells1. Photoresistor light sensors exhibit a resistance that can vary depending upon the intensity of light it detects, as the greater amount of light will generate a lower resistance and vice versa. PV cells, on the other hand, are more environmentally friendly light sensors as a result of their ability to convert solar radiation in to electrical energy through the use of Selenium (Se).
Designed in a way that closely mimics the way ears function in the human body, a sound or ‘auditory’ sensor functions to detect noises or voices of objects surrounding a robot. Typically in the form of a microphone, sound sensors can be used to improve navigation of robots to move according to the sound it receives.
The use of both temperature and humidity sensors that are incorporated into both the internal and external infrastructure of robotics is useful in ensuring their protection against potentially harmful heat sources.
As shown by its name, contact sensors require the physical contact of another object against the robot to trigger a response by the robotics. Some examples of a contact sensor can be in the form of a push button switch or tactile bumper, all of which can be initiated to cause the robot to do a task such as turning, reversing, switching on a LED, etc2. As the technology of contact sensors continues to increase in sensitivity, capactive contact sensors have been developed, which are only capable of detecting the touch of a human being, such as that which is utilized in touch screens. Contact sensors can also be useful in establishing limitations on the ranges of movement that the robot is capable of achieving.
As an additional sensor that it used to establish the distance between the robot and nearby objects, proximity sensors can include infared (IR) transceivers, ultrasonic sensors or photoresistors. Each of these proximity sensors function under a similar mechanism by transmitting electromagnetic radiation or creating an electrostatic field that will be sent to the robot receive for analysis.
Pressure sensors for robotics can come in a wide range of options including load cells, pressure indicating films and tactile pressure systems. The development of highly sensitive pressure sensors has increased in demand as a result of the interest in designing robotic hands that can be incorporated into manufacturing industries to pick up and place objects from one location to another.
These types of industries typically require human operators to repeatedly perform the same tasks, which can not only become a mundane workday but also pose a potential risk to workers when heavier objects are involved in these processes3. Therefore, in an effort to reduce potential risks to humans while also eliminating the time, costs and energy required for this type of labor, researchers have been highly interested in improving the technology of pressure sensors, especially those incorporated into robotic hands.
- “Types of Robot Sensors” – Robot Platform
- “A Guide to Sensors” – Super Droid Robots
- Almassri, A. M., Hasan, W. Z. W., Ahmad, S. A., Ishak, A. J., Ghazali, A. M., et al. (2015). Pressure Sensor: State of the Art, Design, and Application for Robotic Hand. Journal of Sensors. DOI: 10.1155/2015/846487.