Servo Assisted/Joystick sailing dinghy

[albentley]

I am currently working on a project building a sailing dinghy with a integrated joystick control system - very similar what is found on some of the sailability boats such as the Access 2.3 etc.

Essentially I am looking to control the rudder and mainsheet from a single joystick. I know this is 100% feasible but can't find any resources on the design and manufacture of such a system! I have books on control systems theory but these are not the most practical.

At the moment my plan is to use PIC microcontrolled chip (programmable) which will take input from a joystick and output to a couple of DC servos (some kind higher torque version of a RC servo).

The price of all this kit is mega expensive, around £300, so I wanted to get feedback to see if anyone here has any experience of kitting out a dinghy for joystick sailing or knows any useful books/resources on the subject.

Thanks

Al

[Stumble]

I have never tried what you are attempting, and I am a little concerned about the amount of battery power you would need to operate this, but if you want to move forward I would do a google search on RC model sailing. Particularly the US J Boat class http://www.OfficialJClass.org/ which at 8 foot long and 80-90 lbs.

I would think that the type of joystick control you are hopeing for may be a tad optomistic, but these guys are likely to understand the principals that could be scaled up to a man sized servo actuated boat.

[NordicFolkboat]

What are you trying to accomplish with this? Radio control? Sailing for handicapped?

One advantage with actually being in the boat is that you can feel the forces on the rudder and the sheets. You'd have to write software for this. Knowing when the boat is about to capsize, etc. Expect having to build in a lot of sensors such as wind indicator, accelerometer to measure list, etc.

The sheets would require a very strong (and thus expensive) servo. Maybe a winch with a clutch that can be released to quickly bring out the sheets? You can also use a servo rudder at the end of the main rudder, as it's done on many aircraft. And a clubfoot jib means you only need one sheet assembly for the foresail, not two.

[Fanie]

Hi Al,

I'm working on something similar, and I have also done it on my power boat a year or so ago, but has since converted back to the mechanical. Got sick of everyone wanting to know where the steering is and repeating the same boring story

If I could make a suggestion, use something like wiper motors, they have enough torque, off the shelf, easy to control and less expensive than servo's.

I can also help you with circuitry if you're interested. Pics are easy to do it with, don't know what you have, know or use for development though...

The more expensive is the position feedback sensors, since they should use a magnet and hall switches you can pot to waterproof, one has to use mu-metal for shielding if you expect the compass to still operate.

[Fanie]

I am a little concerned about the amount of battery power you would need to operate this

Power consumption doesn't have to be a lot, it mostly depends on the load you have to shift and how often you do control. The wiper motor draws little current... 200mA with no load, but can go to around 10A or more when it has to push the boat's weight. I would think you have to have some power assistance like a solar panel or wind power generator that gives something back. One can design the setup so that all is within the expected ratings and capabilities.

[albentley]

The reason I am doing it is for a project at uni, essentially to add an extra feature to a dingy a group of us are designing and building. Its not worth asking me why I am doing it as I know no normal person would do such a thing without a good reason.essentially I am responsible for creating the system and theres not much else to say apart from if I don't do it I'll get no marks!

Fanie

I'll definitely check out wiper motors as the servos I would need to provide enough torque are very expensive. I am planning to place the rudder shafts directly over the centre of effort to minimise torque on the motors.

Might ask your help with some of the circuitry, will hopefully know soon what I am going to be using.

Do you know any of the basic components that are used in some of the disabled boats? Are they using servos or wiper motors? any PIC chips involved?

thanks

al

[Fanie]

What is a disabled boat ? I assume you mean for disabled people. As far as I know many of the bigger boats use electrical/mechanical stuff for their controls and is nothing new.

Any motor with position control is a servo motor, so don't put a wiper motor in some low category. They are tough little motors. You can of course go buy a control mechanism (with a wiper motor in ) for a lot more. They'll just hide the motor. You can keep water from inside it with a little innovation,

First work out the travel distances you want and the forces involved, as well as the speed the travel must happen at.

Usually the bigger the force the slower your movement will be forced to be.

You get different size motors too, the bigger ones are mostly 24V but works well off 12V, but also much more expensive. Two motors working together is also an option.

You can use any uP to do the control, I just happen to use pics.

[NordicFolkboat]

You're apparently not building a boat for disabled people after all, but if I may digress: Consider adding wheelchair accessibility to it as well. Then you have yourself a boat with a useful application, not just an overly complex and expensive one.