What is robot, Robot Control Methods

According to the Robot Institute of America (1979) a robot is:
''A reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks''.

According to Webster a robot is:
'' An automatic device that performs functions normally ascribed to humans or a machine in the form of a human.'' Another simpler and general definition of robot is: A robot is a programmable electromechanical system that can gather information from its environment ( sense ) , use this information and make decisions ( plan ) and follow instructions to do work ( act ). From this definition we can determine what is not a robot. A robot must have a programme and sensors to interact with its environment and to decide its actions. However, it is unfortunate that the market for robots is crowded with toy models with no roboic functions, sometimes residing with real robots in the same manufacture's line.


Stationary Robots: Robotic arms, computerized machine tools, and most other Industrial Robots which are fixed in one place can be thought in this category. The most commonly used configurations of the industrial robots are; articulated robot arms, cylindirical coordinate robot arms, scara robot arms and cartesian coordinate robot arms.

Odin Underwater Robot
Ground Robots:As it can be concluded from the term these robots operate on ground surfaces on earth or another planet. The sub categorization of those can be made by their drive train as wheels, tracks or legs.

Aerial Robots: These robots are unmanned aerial vehicles likes robotic planes and helicopters.

Microgravity Robots: These robots are designed to operate in low grativy environments like Earth's orbit.

Underwater Robots: The robots which are designed to operate underwater and great depth.


Teleoperation: In this control method , human operator controls a robot from a distance that is too great for the operator to see what the robot is doing ( radio controlled toy cars are not considered teleoperation systems.) The operator and robot have some type of master-slave relationship. Mostly, the human operator sits at a workstation and directs a robot through some sort of interface. Sojourner, the Mars explorer robot of NASA is an example of teleoperated robots.
Teleoperation has some disadvantages because many tasks are repetitive and boring. Also, the camera may not be transmitting new images very fast because the communication link has a limited bandwidth. Because of those problems and many others like time delay and teleoperator needs other control methods were developed.

Nasa's Testbed for Teleoperation
Teleprence: Telepresence aims for what is popularly called virtual reality, where the operator has complete sensor feedback and feels as if she were the robot. If the operator turns to look in a certain direction, the view from the robot is there. If the operator pushes on a joystick for the robot to move forward and the wheels are slipping, the operator would hear and feel the motors straining while seeing that there was no visual change. This provides amore natural interface to the human, but it is very expensive in terms of equipment and requires very high bandwidth rates. It also still requires one person per robot. This is better than traditional teleoperation, but a long way from having one teleoperator control multiple robots.

Autonomous Control: Controlled by computer, with sensor feedback, without human intervention. Computer control is required for intelligent robot control. In this type of control, the computer may send the robot preprogrammed positions and even manipulate the speed and direction of the robot as it moves, based on sensor feedback. The computer can also communicate with other devices to help guide the robot through its tasks.

Semi-Autonomous Control: It is often called supervisory control, where the remote is given an instruction or portion of a task that it can safely do on its own.

Offline Programming: Use of computer software with realistic graphics to plan and program motions without use of robot hardware.

Lead-Through Programming: The human operator physically grabs the end-effector and shows the robot exactly what motions to make for a task, while the computer memorizes the motions (memorizing the joint positions, lengths and/or angles, to be played back during task execution).

Teach Programming: Move robot to required task positions via teach pendant; computer memorizes these configurations and plays them back in robot motion sequence. The teach pendant is a controller box that allows the human operator to position the robot by manipulating the buttons on the box. This type of control is adequate for simple, non-intelligent tasks.