It uses four hydraulic motors to drive each wheel, there will be two hydraulic piston pumps, which will power each the left and the right side of the wheels. Then I would need some sort of electronic actuator of some sort, to control the forward and reverse of the piston pumps to control the wheels. The joystick with control the forward and back and left and right steering. There will also be an actuator to control the articulated steering. I hope that's little more clear.