Parallel robot

A parallel robot is a device for performing manipulations, where the end effector is connected to the base via multiple kinematic chains. Any two chains thus form a closed loop. This is opposed to classical open loop mechanisms such as the serial robot robotic arm (e.g. articulated robots such as jointed arms).

File:Delta robot.png

Technical drawing of a delta robot, a common type of parallel robot, showing the closed loops formed by multiple connections.

Parallel robots are usually faster than traditional articulated robots, since the motors can be mounted on the base, thus saving weight. They are also stronger than serial robots because the end effector is connected to more links. Another benefit is that the error of the end effector is less than the errors of serial robots since the errors are averaged (as opposed to being additive as in serial robots). However, parallel robots are usually more limited in the workspace; for instance, they generally cannot reach around obstacles. The calculations involved in performing a desired manipulation (forward kinematics) are also usually harder and have more than one unique solution (maybe up to 40 solutions!)

Two examples of popular parallel robots are the Stewart platform and the Delta robot.