Main Parts of a Robot

A robot has five main parts:

1. Arm
2. Controller
3. Drive
4. End Effector
5. Sensor

Arm
The arm of the robot is a significant part of the robotic architecture. It positions the End effector and the sensors that the robot will require. Most arms resemble the human limb-the arm. Some of these arms have many complex parts including fingers, wrists, and elbows. This enables the robot different methods of movement.

Seven degrees of freedom are needed for a robot to reach all points in its work envelope. Each direction a joint can go gives an arm one degree of freedom. Simple robots usually have three degrees of freedom-it can move in three ways: up and down, left and right, and forward and backward.

To determine what each degree of freedom means and represents:

First degree of freedom is called a shoulder pitch. To find your arm's first degree of freedom, point your entire arm straight out in front of you. Move your shoulder up and down. The up and down movement of the shoulder is called the shoulder pitch.

Second degree of freedom is called an arm yaw. Point your entire arm straight out in front of you. Move your entire arm from side to side. This side-to-side movement is called the arm yaw.

Third degree of freedom is called a shoulder roll. Point your entire arm straight out in front of you. Now, roll your entire arm from the shoulder, as if you were screwing in a light bulb. This rotating movement is called a shoulder roll.

Fourth degree of freedom is called elbow pitch. Point your entire arm straight out in front of you. Hold your arm still, and then bend only your elbow. Your elbow can move up and down. This up and down movement of the shoulder is called the elbow pitch.

Fifth degree of freedom is called a wrist pitch. Point your entire arm straight out in front of you. Without moving your shoulder or elbow, flex your wrist up and down. This up and down movement of the wrist is called the wrist pitch.

Sixth degree of freedom is called a wrist yaw. Point your entire arm straight out in front of you. Without moving your shoulder or elbow, flex your wrist from side to side. The side-to-side movement is called the wrist yaw.

Seventh degree of freedom is called the wrist roll. Point your entire arm straight out in front of you. Without moving your shoulder or elbow, rotate your wrist, as if you were turning a doorknob. The rotation of the wrist is called the wrist roll.

Controller
The controller functions as the "brain" of the robot. It can also network to other systems so that the robot may work together with other robots or machines. Controllers can become very complicated. There are many computer-based controllers on the market and many robot languages, such as Prolog.

Drive
The drive is the engine of the robot. It enables mobility and movements between the joints of the arm. It can be powered by air, electricity, and/or water.

End Effector
The End Effector is the hand connected to the arm. In humans, the End effector is the hand. However, in robots, the End effector can be of many different things. It could range from a being a tweezer, to a blowtorch.

Sensors
Sensors provide a robot with feedback so that it can "understand" its surroundings-otherwise a robot would be not only blind, but also deaf to its environment.

A few common kinds of sensors are listed below.

• Cameras - Cameras are inexpensive and usable for many kinds of imaging applications. They enable a robot to process its environment so that it can move freely without bumping into something.
• Range finding devices - There are four basic techniques for distance measurement using electro magnetic radiation. They are Doppler methods, interferometry, phase comparison, and pulse timing.
• Sonar sensors - These kinds of sensors work by measuring the time it takes for an acoustic pulse to propagate through air or water, reflect from the environment, and finally return to a detector, is proportional to the distance to that object.