What is a sensor?
Humans understand the world through various sensory systems, such as touch, smell and taste, and so on. Through our vision, we know that it is an orange carrot with a green cap; through the sense of taste, we can taste the taste of carrot silk.
The sensor is the sense of touch, smell and taste of an object. It is a device or device that allows an object to feel the signal being measured and can convert this input signal into an output signal according to a certain rule. Suppose the robot is beaten, and the pressure is the input signal. The sensor changes it to a signal that the head can understand according to its own rules, and the head will respond when it receives the output signal.