Spartan ROV

[ltdcruze]

Sneak peak at the GUI. CAD drawing and electronic ideas to come soon.

[ltdcruze]

So my team has decided on a few things for the Spartan ROV.
This year we will not be using (compared to last year when we did use these):
PVC Frame
Java
TV cameras (as I call them)
This year we are going to go with:
Plastic (poly carbonate or something similar) frame
Visual Studio (C# and VB)
Webcams

The reasons for these changes are inefficiencies from last year's ROV, and we all have learned more so we can use these other technologies.

[ltdcruze]

So progress is going slower than I hoped, but at least we are making some.
We decided on using an Arduino to be the brains of our ROV. We have already started coding it and things are turning out good.
We came up with some nice designs that I think all ROVs will be able to use. First I'll describe our software designs, followed by electrical, and finally hardware.

Software

Running C on the Arduino, the actual Arduino code is very simple, and all it does it write values to pins, and reads the pins and sends them back to the GUI, which is written in a mix of VB and C#. The GUI is a little more complicated because there was so many things to do. First we made a nice interface, then we made controls for the thrusters with keyboard and mouse controls, using the arrow keys to go forward, backwards, turn left, and turn right. For altitude, to go up we used page up and to go down we used page down. We also made a speed control, ranging from 1 to 5, 1 being the slowest and 5 being the fastest. Once we got to coding arm control we got stuck so we decided to make 2 modes, thrust mode and arm mode. In thrust mode you cannot operate the arm, and all functions for the thrusters apply. In arm mode, the thrusters switch to "maintain" in where they maintain the position of the ROV while the user uses the arm, using the arrow keys. While in maintain mode though, using the arm could move the ROV unintentionally, so we used a gyroscope sensor to sense and record any movements. The code will then interpret the data and tell the ROV to move back to its original position. The last part of the software was importing webcam feed, which was really easy and simple, it just imports the feed and displays it.

Electrical

For control of the thrusters we simply have an Arduino hooked up to several relays which control the direction of the thrusters, connected to a voltage regulator to control the speed. The gyroscope is a hacked Wii Motion Plus which used I2C which was easy to interface to the Arduino. Our tether will consist of a positive and a negative from the power source to our circuit, and Ethernet for data. I wish I could be more descriptive but we haven't really worked on the electrical yet.

Hardware

After looking at 2011 MATE technical reports, we really liked the hardware design of Purdue's ROV Hybris. We plan on making a design similar to that (please don't get mad at us Purdue ). We are on a somewhat tight budget, so we are going to change some of the components from Hybris to a more affordable ones. Some of these include: plastic base instead of aluminum. Aluminum is rather expensive and our CNC machine cannot cut it, but it can cut plastic. We will also be using bilge pumps instead of Seabotix thrusters. Seabotix thrusters are really expensive, and I hope Purdue got those for free in a sponsorship!

I'm sure anyone who has some experience building ROVs can see many problems with my design, and I hope they tell me. Constructive criticism is wanted, as well as questions as I would like to help as many people as possible.

- Ltdcruze

[derelicte]

my only suggestions would be to incorporate a joystick or gamepad into you controller. they will allow you much finer control of the rov than the keyboard.

also, if all you are doing is reading and setting the state of the i/os on the arduino, you might want to look at the firmata firmware. I think they have already done that for you.

good luck!

[ltdcruze]

We were actually thinking of an Xbox 360 controller. Do you have any suggestions for button layouts?

[derelicte]

that will work. I use a wii classic controller to control our rov. the left analog stick up/down controls the vertical thruster. the right analog stick controls left/right/forward/backwards. the left shoulder button enables/disables the vertical position hold and the right shoulder button enables the high speed range. trim is controlled by the d pad. home resets controller and recalibrates the sticks.

I currently don't have any functions associated with the 4 buttons, but our rov doesn't have any extra features like gripper, lights on/off, etc.

[ltdcruze]

Thanks for the input. I'll get started on coding an Xbox controller to work as soon as we get a wired controller or a plug n play for a wireless. It looks pretty easy to do with XNA. Are you waiting for 2012 MATE rules before you come up with an arm design like us?

[ltdcruze]

Sample layout

[thegadgetguy]

Are you using vectored thrusters, or are you going for the standard two thruster approach?

[derelicte]

Thanks for the input. I'll get started on coding an Xbox controller to work as soon as we get a wired controller or a plug n play for a wireless. It looks pretty easy to do with XNA. Are you waiting for 2012 MATE rules before you come up with an arm design like us?

that layout looks fine. you may find a better layout once you get the rov in the water and start to use it. I did.

our rov is purely to play with in our pool so we don't have a need for an arm. maybe in a few years when my kids get older we'll think about mate.

it is documented here:
viewtopic.php?f=18&t=444