Delta Robot is one of Parallel Robot:
Parallel robot uses several serial chains to support a single platform, or end-effector. The end effector (hand) of this linkage (arm) is directly connected to its base by a number of separate and independent linkages working simultaneously.
A Parallel robot arm is designed so that each chain is usually short, simple and can thus be rigid against unwanted movement. The off-axis flexibility of a joint is also constrained by the effect of the other chains.
Errors in one chain's positioning are averaged in conjunction with the others.
A further advantage of the Parallel robot arm is that the heavy actuators may often be centrally mounted on a single base platform. This reduction in mass along the arm permits a lighter arm construction, thus lighter actuators and faster movements. This centralisation of mass also reduces the robot's overall moment of inertia.
A drawback of Parallel robot arm is their limited work space.
Another drawback of Parallel robot arm is their nonlinear behavior: the command which is needed for getting a linear or a circular movement of the end-effector depends dramatically on the location in the work space and does not vary linearly during the movement.