Parallel manipulator

A parallel manipulator is a mechanical system that uses several computer-controlled serial chains to support a single platform, or end-effector.

Perhaps, the best known parallel manipulator is formed from six linear actuators that support a movable base for devices such as flight simulators.

The ball joints are passive: simply free to move, without actuators or brakes; their position is constrained solely by the other chains.

Static representation of a parallel robot is often akin to that of a pin-jointed truss: the links and their actuators feel only tension or compression, without any bending or torque, which again reduces the effects of any flexibility to off-axis forces.

A further advantage of the parallel manipulator is that the heavy actuators may often be centrally mounted on a single base platform, the movement of the arm taking place through struts and joints alone.

A manipulator can move an object with up to 6 degrees of freedom (DoF), determined by 3 translation 3T and 3 rotation 3R coordinates for full 3T3R mobility.

[2]  For example, the 3 DoF Delta [3][4] robot has lower 3T mobility and has proven to be very successful for rapid pick-and-place translational positioning applications.

Conversely, at a singular position, a force (like gravity) applied on the end-effector induce infinitely large constraints on the legs, which may result in a kind of "explosion" of the manipulator.

Major industrial applications of these devices are: They have also become more popular: Parallel robots are usually more limited in the workspace; for instance, they generally cannot reach around obstacles.