Cartesian Co-ordinate Robots
This structure is most often seen in machine tools and co-ordinate measuring machines due to its high rigidity. It produces a Robot that is very accurate and repeatable but which lacks flexibility as it cannot reach around objects. These robots are very easy to program and visualise but require a large volume to operate in. They are mainly used for pick and place operations and operations requiring great accuracy. Their linear joints are difficult to seal and this makes them unsuitable for working in damp and dusty environments.

Cylindrical Co-ordinate Robots
Very similar to the Cartesian co-ordinate robots these robots have good rigidity and are good for jobs requiring straight line moves. Programming them is simple as their motion is easy to visualise and they are good for reaching into cavities which makes them ideal for machine tending. The disadvantages of these robots is their inability to reach around objects and the amount of clearance required behind the robot. The linear joint makes them unsuitable for working in dusty or damp environments as it is difficult to seal.

The polar co-ordinate robot structure was the first one to be used in industry. The main reason for this was that it was ideal for hydraulic drives. Since the advent of all electric robots this structure has been all but replaced by the jointed arm robot but many of the old hydraulic robots are still working well in industry doing spot welding and many other tasks.
A notable exception to this is the pendulum robot. This structure is effectively a polar robot hung from a gantry as a pendulum. It produces a very fast accurate robot as the centre of mass is at the centre of rotation of the major joints giving it a small moment of inertia. Pendulum robots are currently used for assembly, welding, gluing etc.

Next >> Modern robots are driven by brushless AC servo motors

Tech Materials (Free)

Robot Behaviors Exploring the T-Maze: Evolving Learning-Like Robot Behaviors using CTRNNs
Humanoid Robotics A Biochemical Subsystem for a Humanoid Robot
Industrial Automation Systems Applying Agents for Engineering of Industrial Automation Systems
Robot Team Cooperation A Descriptive Model of Robot Team and the Dynamic Evolution of Robot Team Cooperation
Kuka Robots For ONU ONU Robotics Technology Center of Excellence, powered by KUKA Robotics Corporation
Augmented reality Annotation System for Robotic Application
Modular Robots Self-Reconfiguration Planning Of Identical Modules
Autonomous robots A New Approach To Robotics
Robotic Mounting Flat Panel Displays With Robotic Mounting
Calibration of Industrial Robots A Photogrammetric Robot Calibration System Based On Off-The-Shelf Low Cost Hardware Components

More...

Amazon Books

	Creative Projects with LEGO Mindstorms by Benjamin Erwin Buy new: $20.64 / Used from: $13.00 A good place to start, especially for kids, with Lego Mindstorms
	A Practical Guide to Behavior-Based Robotics by Joe Jones Buy new: $20.67 / Used from: $15.13 Very good for programming not so much behavior as control. Language and controller agnostic