Student-built robots whizzed, whirred and clattered around a make-believe lunar surface with the nimbleness of R2-D2 yesterday at Madison High School. The high school engineering event, which drew schools from across the county, was a scrimmage for the San Diego Regional FIRST Robotics Competition next month at the Sports Arena, reports SignOnSanDiego.com. Nevertheless the competition was fierce. The robots’ assignments were to scoop up balls, load them into hoppers and lob them into cages. They bumped into each other, misfired balls into the audience and evoked both pride and laughter from their young inventors. The machines were controlled by the student, but they also had to work on their own guided only by a program their architects devised.