A plow is a passive system that moves objects without picking them up. They are the easiest to build but are not very common in VEX robotics competitions since they have minimal functions.

Take a look at the VEX curriculum on object manipulators to learn more.

A scoop applies force underneath an object such that the object can be elevated and carried. This is also a passive intake system since no motors are used on the object manipulator. 

​This type of object manipulator depends on gravity to hold the object on or in the scoop.

A friction grabber applies force to an object in at least two places, allowing the object to be pinched or grabbed. The friction grabber can hold objects securely and generally provides the most control over objects. 

Although many VEX kits come with a claw, students often make friction grabbers to fit the manipulated game pieces better.

As seen in the VEX curriculum for object manipulators, there are a variety of friction grabbers, including top-jaw grabbers and roller claws. One version of a roller claw is shown to the left.

An accumulator is designed to collect and hold multiple objects at a time. This can increase the efficiency of an object manipulation system. However, read the constraints in the game manual, as some games do not allow for more than one game piece to be controlled at a time. 

​Check out the VEX curriculum on accumulators to learn more.