Thruster speed control

[stwendl]

I am looking into modifying my thrusters to control them proportionally in speed depending on joy stick deflection

Benefits of controlling the speed is that one does need full power all the time which saves battery power. The sudden power surge is not only bad for the battery but also hard on the shear pin, prop and what else and really is not needed.
Using pwm power allows applying minimal thrust for docking at a longer time than the current design without depleting batteries or over heating thrusters. Of course at full thrust the same limitations apply.
The controller can detect stall situations and remove power from the motor before any damage occurs.

Side power has hardware that allows you to do this but is very expensive. The joystick is about $800, then you need one ppc800 per motor which is about $2000 each and several slink cables are need to connect all together. If you have an ip model of thruster it needs to be sent in for modification.

I have identified a commercially available motor controller that would do away of the reversing relay at the thruster and which costs 25% of the imtra controller. It won't handle the 800amps of the imtra but our thrusters don't need that much. The main fuse is at 150amps and this controller handles 150 continuous and 200 peak. By removing the electronics at the thruster random starts or failures would be eliminated. The controller would sit in the battery compartment and the bow controller would be right next to the motor there.

This is still in an investigative phase and I have yet to identify a manufacturer of a suitable double joystick either analog (no hold of power) or digital with hold of a settable thrust

Just wanted to get a feeling if there was any interest in the community or perhaps some engineers who might have some input. I would think this to be an upgrade that someone who has replaced shear pins and has a some electrical knowledge can probably do themselves

 

[NorCal]

I would be very interested in this. I hate the all or nothing and the noise. The price to upgrade from sidepower to proportional control is definitely out of my budget. Something like this would be great. I will be watching.

 

[tlkenyon]

Sign me up. This would be a very nice enhancement and probably worth every penny.
TK

 

[stwendl]

Thanks for the interest. Here is what I have so far.

Timing wise, this would not happen until December 2016 after the boating season.

The controllers are $595 each and I doubt I would get enough quantity discounts. In addition a programing device needs to
be purchased, one can program all units. So if there was a group purchase, the cost of the programmer could be shared ($425). That programmer is a piece of software running under windows and some USB to CAN bus dongle.

For a HID (human interface device, fancy word for a joystick type device) I found a micro thumbwheel for $68 ea and two would be needed. Those create 0-5v and 2.5v in center position with return to center. Unfortunately, they are somewhat small about 1 inch wide wheel. This will work but may be a bit too small for some users. Still looking for other solutions.

The next product up would be a joystick type device and the price goes immediately up to about ~$150 upwards. And no the current ones will not work as they are just switches and not proportional.

A more simple and cheaper interface would be a 3 button solution, center button off, left or right buttons for portside and starboard direction. Stay on those buttons and the motor ramps up, double click and you go faster ramp up, triple click full power (instead of waiting for the ramp up). That solution would require some micro controller design which would probably way cheaper than two thumb wheels required above. Bonus would be here to use frequency output to control the motor instead of analog voltages which may be affected by a long run of cables or faulty connectors. In this case, perhaps the existing joysticks could be used instead of buttons to achieve the same ramp up function, but no hold would be possible as the existing joysticks will auto center and turn off thrusters. Still have to figure out a few things.

So we are looking at about at least $1400 + tax/shipping per installation. I think the wires currently in place can be used to carry the analog signal. Would just have to make some connectors to connect the new equipment to them. This way the boat can be reverted if so desired. The relay box at each thruster would need to be disconnected so that the power leads from the controllers can be connected directly to the motor. Each power cables currently in place can probably be reused, and some short new power wires from controller to battery need to be made/supplied ( still need to figure out where best to install this. I would only be able to figure this out for a R27 that I have access to, others may vary a bit)

Compare that to a side-power solution which is about $5000+ (plus wiring depending on how much CAN bus wiring is needed) and a possible modification of the thrusters by side-power. Side power solution user interface has some feedback about battery and truster power. But since we use a shared thruster battery that is a bit less valuable. A fancier user interface allows set and hold power. I have not taken that in consideration.


Still interested.

 

[DBBRanger]

Sounds like a good project for using an Arduino microprocessor as a control unit - is that what you're thinking?

 

[stwendl]

Trying to avoid arduino. There are off the shelf products available to do that. Just need to find them. Cost of doing small run and development is higher than off the shelf products.