Constructing Automated Mining Robot !!!

In this project, I have to build automated mining robot, and investigate about it.

First of all, I need to build the robot.
During building the robot, I met many new functions of the robot, that I did not know.

The shape of the mining robot was totally different with the NXT robot. For mining robot, the NXT is flat and lying over the base (wheels, and supports, which holds NXT). This robot has total of 4 wheels, and looks strong and heavy. Moreover, the robot uses 3 motors, 2 for wheels and 1 for ultrasonic sensor.

When the robot moves, the ultrasonic sensor is made to be movable. There is a black circular base, which holds the ultrasonic sensor. And this base is connected to two cross sticks, which rotates the base. By this function, the robot is able to make the ultrasonic sensor to move.

Moreover, because the motor is reversed, in order for the robot to go forward (front: ultrasonic), the motor has to rotate the wheels backward.

First picture shows the base of the robot, which is without the NXT.
Second picture shows the completed robot, with NXT.
As you can see, the left side is the front of the robot, which is with ultrasonic sensor.