Robot arms
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[edit] Types
[edit] Articulated / Jointed Arm
These are used for arbitrarily high numbers of degrees of freedom, several orthogonal junctions of control axes to enable a large volume of reach & a large angle of attack space. Each axes is in series / nested, with actuators mounted rigidly to the moving platform created by the axis before it. A common configuration is to use 6 or so axes of 100% rotationally-actuated joints, though some may include more or less joints, and may include linear-actuated joints.
Platforms vary: the arm may be mounted on a vehicle, on a fixed trackway, or on a nonmoving base. Manipulators also vary, with various cutting or welding tips being used in addition to robotic friction grippers and vacuum or magnetic grippers.
[edit] Cylindrical
[edit] SCARA robot (multiply cylindrical)
Rotates around 2-3 parallel axes, actuated in a series (nested) manner.
[edit] Parallel
[edit] Delta
This uses 3 blended linear or rotary actuator inputs which are in parallel rather than series, to accomplish translation of a platform. So far, professional efforts have tended to utilize the angular drive delta, which can use lightweight arms, while amateur projects have focused on the linear drive delta, which is less patent-encumbered and can re-use parts from gantry-based projects.
- The Tripods Are Coming - Drives & Controls magazine
- Delta Parallel Robot - The Story of Success - ParalleMIC
- Delta - Reprap Wiki
[edit] Hexapod Mount / Stewart Platform
This uses 6 blended linear actuators on non-locked mounting points (like a ball-and-socket-joint), all in parallel, to accomplish free translation *and* rotation in 6 axes.
- Has nothing to do with six-legged locomotion.
[edit] Cartesian
[edit] Gantry
This is the primary mount for DIY 3D printers & CNC mills. 3 nested axes that are orthogonal to each other and function only in translation, not rotation.
[edit] Spherical / Polar
2 axes of this work only in rotation, while the last functions for translation. Essentially similar to a latitude/longitude/elevation system. While popular early on in industrial automation, this style has fallen out of favor.
