Robotics is the engineering science and technology of robots, and their design, manufacture, application, and structural disposition. Robotics is related to electronics, mechanics, and software. The field of computer science and engineering concerned with creating robots, devices that can move and react to sensory input. Robotics is one branch of artificial intelligence. Robots are now widely used in factories to perform high-precision jobs such as welding and riveting. They are also used in special situations that would be dangerous for humans -- for example, in cleaning toxic wastes or defusing bombs.
Robotics engineers work in the science of robotics, or flexible automation. Most robots are "manipulators"—machines devised to function in place of a human. Some robots function as "walking" machines, or teleoperators, using remote control or sensory manipulators. These engineers use computer-aided design and drafting, and computer-aided manufacturing (CADD/CAM) systems to perform their tasks.

RO-1 / PLTW: Robots with a programmable interface smaller than 1 sq ft. that does a simple routine. Construction materials could be (Lego, fichertechnic, boebots, etc.) Group eligible to participate A and N Scoring Guide for RO-1

RO-2 / PLTW: Any type of computer integrated manufacturing or CIM. This area demonstrates any type of multi-operation assembly or process machinery that uses a programmable interface. Group eligible to participate A & N  - Scoring Guide for RO-2

RO-3 / PLTW: Any type of robot that is 1 sq. ft. or greater that uses a complex interface such as VEX or First Tech Challenge. (any robot that uses a complex interface is eligible no matter the construction material.) Group eligible to participate N and P - Scoring Guide for RO-3

RO-4 / PLTW:First Robotics entries only there will be a group presentation required in this area (we have to remember some robots may not be back from nationals, this could be a problem so pictures, video and documentation could be used in place of the actual robot if the team qualified for nationals.
Group eligible to participate N and P - Scoring Guide for RO-4

Group (A) is for students in grades 6, 7 and 8 who receive instruction averaging less than 6 clock hours per week in the industrial technology subjects (Division) represented by their entry.
Group (N) - Novice or Amateur: a student who is new to the circumstances, work, etc., in which he or she has placed an entry; beginner; tyro: a novice in the entry area. This entry area is for the 1st year the student has entered in this project area. 
Group (P) - Practiced or Experienced: A student who is skilled or expert; proficient through practice or experience: a practiced hand in which he or she has placed an entry.  This entry area is for the student has entered in this project area more than once.