DC Brushless Thrusters
Romulus is equipped with six thrusters. They are some of the best small size thrusters available for applications like the RoboSub competition. They work by using a Magnet array in the hub of the propeller which is driven by matching magnet array attached to drive motor. The set that we have utilizes a 6:1 planetary gear set. They are manufactured by Tecnadyne.
Romulus uses 6 thrusters:
The picture to the right allows a visual aid to the functionality of each thruster.
1 & 2. The vertical control thrusters used to regulate the depth of the vehicle. These two are place symmetrically in order to maintain a level position while descending or surfacing.
3 & 4. The thrusters that control forward and reverse propulsion, These two are also placed symmetrically amidships to maintain steady forward navigation, an important aspect in our vehicle this year.
5 & 6. These lateral thrusters are a new addition to the vehicle this year. These are for horizontal control of the vehicle. We added the lateral thrusters in order to ease position adjustment and avoid turning the entire vehicle just to move over a couple of feet.
This year the biggest change to the thrusters was the addition of the lateral thrusters to ease position control. So far the thrusters have worked flawlessly and the lateral control thrusters have proven to be a huge help in setting up precise positions.
While the team was at the competition in 2011 we added a constant offset to the thrusters. This bias was tuned in through experimentation. Initial tests indicated that a correction of approximately .3 volts in magnitude to the starboard thruster was enough to overcome inefficiencies throughout the thruster/propulsion system and even out unbalanced drag factors. This alteration needs more alterations and design work to be implemented more successfully on the 2012 Navy AUV.
Helpful DC Brushless Thrusters Links:
- Tecnadyne Home Page
- Spec Sheet