Electric Motor is used to actuate and move something in a robot. There have different kind of parts of a robot, like its wheels, legs, tracks, arms, fingers, sensor turrets, camera, or weapon systems. Sensors are used to detect distance, temperature, light, colour etc. Sensors have a huge role to make a robot advanced.
There are different types of motors like AC motor, Brushed DC motor, Brushless DC motor, Servo motor, Stepper motor, DC linear Actuator, etc.
Sensors are applying in robotics to estimate a robot's condition and environment. After taking the information those signals are passed to a controller to enable appropriate behaviour. There is some example of sensors are Light sensor, Sound Sensor, Temperature Sensor, Contact Sensor, Proximity Sensor, Distance Sensor, Pressure Sensor, etc.