They are used in positioning to provide variable programmed motions of loads. "Intelligent" industrial robots utilize sensory information for complex control actions, as opposed to simple repetitive "pick-and-place" motions. They are Industrial robots also used for parts fabrication, inspection, and assembly tasks. They consists of a chain of several rigid links connected in series by revolute or prismatic joints with one end of the chain attached to a supporting base and the other end free and equipped with an end-effectors. Robot's end-effector can be equipped with mechanical grippers, vacuum grippers, electromechanical grippers, welding heads, paint spray heads, or any other tooling. Although similar in construction, an industrial robot is distinguished from a manipulator by the use of programmed control logic as opposed manual control. Pick-and-place industrial robots are used as automatic palletizers. Mobile robots are similar in construction to free-ranging AGVs. They can be powered manually, electrically, or pneumatically. They can be powered manually, electrically, or pneumatically.