At the competition, the students used remote controllers to make their robot pick up different sized objects and place them into goals. The further up the playing field the objects were, the more points they were worth.
Points could also be scored if the robot could grab on to a bar and lift itself off the ground.
Kate said the robots had to be programmed to move autonomously for the first 15 seconds of the game then the rest of the two-minute match was operated by joysticks on a remote control.
She and Logan built their robot with rotating cogs that could push or pull a smaller ball, and a catapult that could be used to throw a bigger ball.
VEX Robotics, the company that runs the competitions and manufactures the robots, gives each competing team a list of the parts and components allowed in construction of the robots, but leaves the designs up to the students.
Kate and Logan were beaten by one point in the finals by another New Zealand team, Lynfield College in Auckland.
All four Otumoetai students were new to the sport.
"Before the nationals, we had last year's Year 13s helping us but then they left for university so we had to do everything ourselves," Kate said.
"We spent every lunch time, most days after school and almost every weekend getting ready, I didn't really have a social life."