ROV motor control system

technotony007

Member
Join Date
Apr 2006
Location
south shields
Posts
3
Hi,

I am an ROV technician with a mechanical background. I am trying to learn PLC’s to enhance my electrical and electronic knowledge for the benefit of my career and hobby. The project, which I am starting, is to build a ROV in a basic form. The list of equipment that I am working with is a laptop, which has a 5-axis joystick attached to it. via its usb port. A serial 9 pin lead to gofrom my laptop to my plc. The plan is run two plc’s. One at the surface and one in the Rov. The Rov basically has 6 - 12 volt dc electric drill motors .the direction of these as I understand up to now is controlled by polarity. The following information I would be most grateful if anyone could help me with is:

  1. What type of plc’s do I requireor suggest using . (8,12, 16 channel, make, etc?)
  2. What type of software platform would I use to program / control the plc, via the joystick in a window environment.
  3. Could I run a camera signal through a plc?
The intention is to have umbilical length of about 100 meters max. I would like to use my computer laptop screen as the monitor, the output from the camera. I would configure the computer to run two programs as I fly the ROV, the first would be the camera software as my eyes , and in the background I would run the Plc software which I would use to control the electric motors . Any help would be gratefully received as I am new to this area of PLCS, and I am very keen to learn.

Regards

Tony

 
1. A PLC generally will not be able to do anything with the camera signal other than switch it via a relay contact. It may be able to control power to the camer via an output.

2. Are you planning on collision detection inputs or possibly feedback from the motors regarding speed and turn position? Or are you expecting full control to be from the operator at remote PC?

3. There may not be any need fro 2 PLCs. The operator's PC should be able to communicate directly with a PLC on the ROV through an umbilical.

4. You may wish to consider wireless control for the PLC (Ethernet?) and a wireless camera such as available from X10. This would probably be after you get a directly wired version of the ROV working.
 
so bernie do you have any suggestions for the software ( or the PLC type )i would use to control/ program the plc . if i was to run the program for just the control the drill motors , by the joystick at the laptop.the thrusters i have 4 angled horizontally and two vertically. the joystick is a standard microsoft force feedback type . any help or were to look i would be grateful.

regards

Tony
 
Skeptic.

From the words you used like 'surface' and 'fly' I assume this is an underwater application. Why keep us guessing?
I wouldn't use a PLC for an underwater application. I would look at an embedded processor board with all the I/O needed. I would then conformally coat it to keep it water and pressure proof . I would also mount water tight connector in the conformal block.

I would use Ethernet for the communications. There are many cameras that can send the information to the controller over Ethernet. I would look at the specification for running power over Ethernet although I doubt this would be enough for a ROV.
The cable can be heavy and affect the ability of the ROV to manuver. This may limit how far your cable can go because a small ROV will not be able to pull it.

This is a lot of work for someone with a mechanical background.
You need to find someone who can do the computer part for you and you should concentrate on the mechanics. This is a big project, more than one person can handle.

Not many have the will and resources to see a project like this through to the end. Wouldn't it be cheaper and easier to buy an ROV ready made? What ever it costs I bet it will be cheaper than rolling your own.
 
Good catch Peter - I didn't clue on the implication of 'surface', 'thruster' and 'fly'. I had a land rover stuck in my head. I second Peter's suggestions.
 
Prolly not

Hey there. I spent years around ROV's in the Navy and offshore, and noone uses PLCs in these applications. I imagine one COULD maybe, but it'd be hard.

The main problem is that an ROV is an ANALOG creature, with all the commands up and down ususally 485 or Ethernet -- thruster commands, camera movements, telemetry data ("where are" data in all axis, etc.)

For all but small ROVs, onboard HPUs power the thrusters (up/down/rotate). Power supplied through the umbilical, of course, to the hydraulic devices.

Fiber normally used for data transfer -- the umbilical is too thick to bend to the fiber's danger point of breaking. Camera data is is...well... video signal, straight back into video cards withing the Pilot computers(PCs).

For this one:
"What type of software platform would I use to program / control the plc, via the joystick in a window environment."

I'd have to say... the PC is the platform, and something like Delphi, VB, C++, etc the software of choice.

Again, I suppose ya could do this. If you can handle all the various analog data/telemetry stuff, VFD your thruster motors somehow, and find small enough/smart enough PLCs to cram in the bottle on the ROV.

Skeet
 
everyone,
thanks for the input everyone sofair , i've myself have been around ROVs for ten years now, and i have a fair idea how data is passed down an umbiical, by fibres and twisted pairs,hydraulic powered thrusters etc. The plc in the rov would be in a watertight and sealed chamber. If i use the pc as the plaform , it has been suggested to a computer Languages like c++ , visual basic etc. I am just a thick old clanky trying to enhance my knowledge , on the elctrical/electronic side of things .That would involve leraning different computer programming , which is a bit involved that learning plcs. What i would be most grateful if anyone could help me with is say : if i used one plc 8 channel say, a laptop , joystick , and a ethernet cable connecting the pc & plc.

1) Is there a basic software package that can be run in a windows xp enviromen,etc . that i can write a basic program for , where by i can control the motors by the joystick , link the 24 v electric drill motors , so if :

1) push joystick forward : four of the horizontal mounted motors rotate clockwise , the further forward i push the joystick the faster they spin.( ramps up the amps i think !!).
2 ) push joystick back : four of the horizontal mounted motors rotate anti/counter clockwise.speed dictated as before.
The same sort of movements for left and right , to spin on the spot in one direction , by twos rotating cw, and two ccw. speed same as before. and the last two commands which would be up and down which would be controlled by the toggles switch on the joystick. this would control two vertical mounted drill motors link together for that function.

Obviously i dont want to spend alot of money , but would love to learn a simple Plc system which help me move forward. Any Pc controlled PLC and software ideais would be greatly apreciated. as i am learning this as a hobby. the camera side of things i have sorted , its just the motor control side i am struggling with.

best regards and thank you again.

Tony
 

Similar Topics

Hello all, In my facility we have multiple 3HP 460V motors that are being controlled by VFDs which drive conveyor belts. The drives are randomly...
Replies
2
Views
172
Hi everyone, This is my first time posting, so please forgive any omissions or mistakes. I am attempting to control the velocity of a stepper...
Replies
18
Views
738
Kindly, has anyone tried to control Lenze servomotors with Siemens S120 drives ? Any special hints ? Have some concerns for the resolver and servo...
Replies
5
Views
177
Dear Members, Hello, we are working on a project and facing an issue with the plantpax 5 PMTR library, we have a bidirectional motor, which has 2...
Replies
6
Views
185
Hi all, New here and new all round to PLC`s. We have a servo drive that runs a cross travel beam backwards and forwards. I am having trouble with...
Replies
3
Views
134
Back
Top Bottom