Let's Make Robots!

Project ABE - XMOS Challenge

underwater exploration for lakes and reefs

- Summary -

More information within the weekend...

About Project ABE

 The main purpose of the project it's to create an autonomus vehicle to explore lakes and reefs. Aquatic Bot Explorer (ABE) its based on a ROV (Remotely Operated underwater Vehicles ) and AUV (Autonomus Underwater Vehicles ) class robots.
       This bot it's powered by an XK-1 processor by XMOS, several boards for sensing: pressure, temperature, depth, etc. Motor control, demux, ADC, etc. are developed.

1.1 Vehicle Design

ABE design consist of three DC motors with special water proof. The control system uses a Fuzzy algorithm for underwater stability, sensed by an accelerometer. three underwater proof servos are used to move each thrusters for different movements.  An illuminated system will be controlled by a light sensor, according to the ambient light. Other measures to consider are: temperature, pressure and water presence inside the bot, in this case will activated an special function to go back to the surface. In figure 1.1.1 its show the 3D model of ABE. The version 5 of ABE it is almost finished and under testing.

 
Fig. 1.1.1 - ABE 3D design.


In the Video shows the process of assembling ABE, this version uses a minimum of parts for ABE version 5.

 

2.1 Circuit Design


 The circuits used in ABE are several boards divided in two main areas: control and sensing. Each board contains the basic circuits to move the bot and obtain vital information from the enviroment. This boards are conected to the XK-1  (Figure 2.1.1)  The control board wich is used for the motors are in pins XD12 - XD23. The sensor and lighting control are in pins XD0 - XD11.


Fig. 2.1.1 - XK-1 pins locations to use for control and sensing boards.


All the boards are put together in cube arrangement that contains: main sensor board, control board, XK-1 and power board. This is ilustrated in figure 2.1.2.


Fig. 2.1.2 - PCB Arragement for X-BOX.
 

Power Board - The PCB uses 7805, 7809 to obtain 5, 9 Volts,output reference voltages and a small DC-DC converter.

Sensor Board - This PCB uses a LM35 for temperature sensing, a basic water precense sensor and a small power circuit to activate the lighting system and an accelerometer for position control sensor.

Main Sensor Board - The main use of this board, its to obtain analog data from the sensor to the XK-1, according to x-linkers[*] ,there is available code for MCP3208 , this  12-bit SAR ADC from MicroChip has 8 input pins, multiplexed to a 100 ksps ADC.  The board will use one of this IC, with an 4017 to multiplex ports to use for control purposes.

 Control Board - This board will take the signals from the XK-1 to control 4 DC motors and up to 9 servos. To achive this task, its use an 74hc595 to send signals control for two L293D. Also, a  4017 will multiplex the signal for the servos.


3 Algorithms Design

3.1 Basic Servo Control

Soon ..

 
3.2 Basic PWM - DC Motor Control

 Soon..

 

4 Simulation and Testing

4.1 -  Trhuster Test

 Soon ...

 

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In my opinion the weight is a litle too much, i would suggest that you use Aluminium moisured with anti corosion liquid!

And a smaller version would improve getting into smaller spaces betwen reefs and posibly sunken ships!

About the camera how will you make it water proof with liquid plastic or ......... i dont know?

Finish this robot soon i must get sceetches for it and start building it! River Danube is waiting ;D

I absolutely love your project but am still a little concerned on the buoyancy issue.  Judging by your photo I estimate there is at least 4-5kg of buoyancy pulling the bot towards the surface.  And that’s a lot of energy wasted if the thrusters have to keep it at a specific depth.

Also is there some sort of gyro sensing the orientation of the vessel?

Again, I love your project but this is so much more complicated then getting the thrusters and servos waterproof.

Great render animation for the video. I have added it to the XMOS YouTube channel favs!
This thursday I´ll post another video...

What kind of operating parameters are you anticipating?

i.e. salt? fresh?

max operation depth?

will it be tethered or be fully autonomous?

Are there any other kinds of self-preservation external sensors, e.g. sonar?

What, essentially, will be it's purpose and what do you hope to do with the accumulated data?

 

thanks! 

Sir,

 I am very interested in this underwater explorer. I would like to see the complete schematics, a partlist and where to get the parts and if possible part numbers and the manufacturer. I would also like to see how you waterproofed everything. Did you ever think about adding a wireless micro video camera to this? I really hope you can help me out. I really appreciate your work that is going and already went into this project.

 

Towlieboy78

That is great - Cant wait to see it!

Looking good!

How are things going with it?

In this week I will post a few videos of: control testing, animation movements. Also algorithms descriptions. I´m editing all the info right now to post it...

To your pervious post about depth.

A simple pressure transducer and a small circuit would fix your problem. All that you would need in the program is to turn the auto depth on/off and the sub will hover at the depth the circuit was turned on. Second you can have an add on to the circuit that will reset every time you thrust up/down past 50% and this will reset auto depth to your new depth.