Hello,
I plan to build an aquatic drone based on the BlueROV to track target that will swim at speed up to 6km/h (3.7 mille/h). Is the BlueROV and its T200 Thrusters able to move at this speed (horizontal speed, no need of high vertical speed)?
Thanks
GReg
The speed of the ROV relates to the continuous thrust of all of the motors, and the total weight of the ROV, as well as its shape (hydrodynamics). The buoyancy will also play an important role.
Without quite afew details of your setup, it’s not possible to say.
I absolutely agree with you I need to provide you with some additional data:
weight: I want something autonomous, so it means with a battery pack on-board (no wire between the Rov and an operator), a Rasberry Pi + sensor + camera, let’s say 0.6Kg. So the total weight will be "Naked Blue ROV " + my stuff = 3.73+0.6 =4.33 Kg
buoyancy = the watertight enclosure is 12" long and 4" of diameter = 30.48 cm (L) and diameter (D) of 10.16cm , so the volume is LPi D^2/4=2.47 litters , so the ROV’s weight in the water (no salt) will be 1.86 Kg.
shape: I plan to have no add-on to the original ROV, so the worst case will be the horizontal movement of the cylinder whose face is Pi* D^2/4 = 324.3 cm^2
In the water the Force to mode the LxS cylinder at V speed is F = 0.5pV^2SC where
p is the density
S; the surface
C: drag coefficient = log (VL/nu -2)^2 with nu=1.1410^-6
Do you confirm that with 4 Thrusters I will be able to achieve 4.6 Km/h (with all the approximation)
You’re on the right track, but a simple free body diagram is needed. Can you draw the basic ROV with the vertical buoyancy force (as a vector), the drag force (as a vector), and the force provided by four thrusters.
The thrust provided by a single T200 thruster is up to ~5Kg (~12 pounds) at 12V. The thruster will be consuming around 22A at full thrust. You then need to do a sum of forces along the x and y axes, and use F (force) = M (mass) x A (acceleration) to get the maximum acceleration. You can then use this in the velocity equation to get the speed. Note that this would be for MAX thrust, so you should actually reverse the calculations to determine what force the actuators will need to provide to get to a certain velocity.
