For their final project, our students must design, build, and program a robot that can successfully compete in a sumo arena. Sumojaeger is an example that we provide.
There are two main innovations with Sumojaeger. First, the Medium Motor is programmed to rotate the IR sensor, granting the robot a 180-degree, forward-facing, horizontal FOV—much in the manner seen here; second, the two Large Motors are connected via an adder mechanism, allowing for twice the torque without loss of speed. The overall efficacy of the design can be seen here. (Sumojaeger starts in the upper-right corner.)
Attached are partial .lxf building instructions; note that all of the required LEGO elements are available in 31313.