Question text A robot is used as a computerized postal delivery system. It drives around the corridors of a set of offices picking up and delivering post. If the robot is close to a worker it stops and waits until the worker moves away. (a) A proximity sensor is used to detect how close to a worker the robot is. Describe the role of the microprocessor in stopping the robot.
Answers
Answer:
Proximity sensing is the ability of a robot to tell when it is near an object, or when something is near it. This sense keeps a robot from running into things. It can also be used to measure the distance from a robot to some object.
The simplest proximity sensors do not measure distance. A bumper can be passive, simply making the robot bounce away from things it hits. More often, a bumper has a switch that closes when it makes contact, sending a signal to the controller causing the robot to back away. When whiskers hit something, they vibrate. This can be detected, and a signal sent to the robot controller.
A photoelectric proximity sensor uses a light-beam generator, a photodetector, a special amplifier, and a microprocessor. The light beam reflects from an object and is picked up by the photodetector. The light beam is modulated at a specific frequency, and the detector has a frequency-sensitive amplifier that responds only to light modulated at that frequency. This prevents false imaging that might otherwise be caused by lamps or sunlight. If the robot is approaching a light-reflecting object, its microprocessor senses that the reflected beam is getting stronger. The robot can then steer clear of the object. This method of proximity sensing won't work for black objects, or for things like windows or mirrors approached at a sharp angle.