What makes a machine different from a Robot? What improvisations convert a dumb machine into a Robot? Though the basic construction of a robot is very much build on the structure of a machine but there are certain things like, actuators, sensors and controllers added to it which makes it a Robot.
The basic building blocks of a robot are very similar to that of machines. As a machine has moving parts or members connected to each other through different types of joints, driven by some motor or any other driving mechanism and moving in synchronization with each other to execute the specified operation. In the same way the basic structure of a robot is similar to that of a machine, but there are some advancements or additions to the machine which make it a robot.
In robots the simple driver motors are replaced by the servo motors, which are more accurate and fitted with sensors made up of transducers to provide feedback. There is more number of actuator motors in the robots as compared to the machines, which generally have single driving motor. Also there are controllers, governing the operations of different sensors and actuators in the robots, provided with the instruction set and they give command accordingly to the actuators and receive feedback from the sensors. These are some advancement in robots over machines.
On addition to the frame of a machine the components of a robot can be broadly named as:
Actuators: Actuators move the different members of the robots by the specified amount and the specified point of time, angle or the linear translation, as per the commands received from the controllers. Along with the motion actuators also provide the requisite force to the members. Actuators can be electrical like permanent magnet D.C. motors, stepper motors, solenoids, printed armature motors or hydraulic like linear cylinders, hydraulic motors and actuators in robots can also be pneumatic. Read more about Electrical Actuators, Hydraulic Actuators, Pneumatic Actuators.
Sensors:
What makes a robot special and advanced than a machine? It is the proper use of sensors, at right places, in a robot. Sensors as the name suggest can sense the surroundings and the different objects with which it is interacting. Sensors provide feedback to the controlling system about the motion of actuators and other members, how much they have moved, what is the speed, acceleration and also sensors can provide information about pressures and forces which are acting upon. Some advanced sensors such as optical sensor, thermal sensors and vision sensors which can create more vivid image of the surroundings and provide more detailed information to the controlling system.
Processors and Controllers: To give the starting command to the actuators, receive and process the feedback information from the sensors and then provide the corrected signal to the actuators, Processing and Controlling system is required. Controllers are programmed as per the function to the robot; certain software and programmers are used for this purpose. The feed back information received from the sensors is passed through the signal convertors where is made usable and passed on to the processors which in turn disseminate the modified signals.