Cartesian and Gantry Robots: A cartesian coordinate robot (also called linear robot) is an industrial robot whose three principal axes of control are linear (i.e. they move in a straight line rather than rotate) and are at right angles to each other.The three sliding joints correspond to moving the wrist up-down,in-out,back-forth. Among other advantages, this mechanical arrangement simplifies the Robot control arm solution.
Cartesian coordinate robots with the horizontal member supported at both ends are sometimes called Gantry Robots. They are often quite large.Industrial gantry type cartesian robot is applied on CNC lathes production line for continuous parts loading and unloading. It performs 3-axis (X, Y, and Z) linear movement in high speed performance to save numbers of operators. In addition, the robot is able to handle heavy loads of pick and place parts feeding procedure with high positioning accuracy. Some special requirements might be low noise and customized supply table, which is made according to number of storage. Since handling is usually above the CNC, overhead gantry is also a common term to describe this type of robotic arm. Overhead design is suitable for most automation system.
A popular application for this type of robot is a computer numerical control machine (CNC machine). The simplest application is used in milling and drawing machines where a pen or router translates across an x-y plane while a tool is raised and lowered onto a surface to create a precise design.
" Cartesian-robot features "
Cartesian robots’ total cost of ownership has decreased 25% over the last five years due to pre-parameterized control packages, online design tools, and economies of scale. So now they are viable options for small to midsize manufacturers looking to automate storage-and-retrieval, pick-and-place, liquid-dispensing, packaging, and auxiliary machine-tool operations.
In addition, Cartesian robots:
- Consist of standardized components that combine into robots that cost less than purpose-built robots. This lets end users quickly assemble robots piece by piece rather than customize machines for every application. In some cases, standardized mounting brackets with centering rings replace traditional dowel pins on module guideways to further simplify assembly.
- Can be specified with online tools. Online software takes some of the confusion out of how to leverage the mix-and-match modularity of Cartesian robots. It lets engineers plan linear motion for single or multiaxis automation by entering the mass to be moved and the required stroke. In the past, designers ordered Cartesian-robot subcomponents using individual part numbers from different vendors. Now, engineers can often order integrated robot modules — including rails, servodrives, mechanical elements, and controls — with one vendor part number.
- Are safer. On legacy Cartesian robots, safety circuits connect to controls that introduce delays as they command the motor’s drive amplifier. Newer robots have intelligent servodrives instead, with safety circuits that accelerate response. These circuits also let Cartesian robots operate in reduced-torque mode, similar to the teach mode of SCARAs and six-axis robots. These modes let operators enter the robot’s safety cage and manually “teach” the robot coordinates to get a job done. To prevent injuries, robots in this mode shut down if it contacts the trainer.