Second hand robots can be either controlled by a human operator or by a computer. We all have broadly seen that there is not a standard definition that can explain the meaning and functionality of a robot.
However, there are several characteristics of a robot. The first and essential characteristic of a robot is sensing. Unless it is not able to sense its surroundings, it might tend to work differently. Therefore, robots are given sensors such as light sensors, touch and pressure sensors, chemical, sonar and taste sensors. All these sensors will give a robot awareness of its environment.
Another important characteristic of the robot is their movement. Its movement can made either through rolling on wheels, walking on legs or propelling by thrusters. Though robots can perform like human but they too need energy to perform their work. A robot can be solar, electrically or battery powered. The energy spent by the robot will depend on what works or functions your robot is assigned to perform.