Development of a motion control system for underwater gliding vehicle

The authors have been developing a gliding type underwater vehicle, an autonomous unmanned underwater robot. The motion of the vehicle is not limited by a tether cable and it can cruise freely in the ocean, using the lift of a wing and changing its weight in the water, repeatedly descending and ascending. It does not have a thruster. An untethered underwater vehicle cannot be supplied energy by a support ship and must be equipped with sufficient energy in its body. In this point of view a gliding type vehicle has an advantage because high propulsive efficiency can be expected using the gliding method (Ura, 1989; Ura, 1990). This paper presents a motion control system using an air pump to change the body weight in water. The depth of the vehicle is controlled by a controller using a depth sensor. The system controls the depth of the vehicle using a buoyancy changing mechanism. The attitude of the vehicle is also controlled by ailerons and a device that changes the center of gravity of the vehicle.