The robot has an ultrasonic sensor and others at the front, allowing it to detect objects in front of it.
The chasis of the robot contanis an Arduino or similar controller, allowing it to process the data from the sensors. The robot will plan a course ahead up until it sees an object in its way, aat which point it will turn 90 degrees right.
The robot has four wheels driven by servo motors, which can rotate as directed to by the controller to travel along the determined plan.
Here's a cool robot video