remote controlled boat

Hi guys. I am in the process of developing a system to allow a boat ( a real one) to be made remote control. The first stage of this process would be to create a mechanical actuation system whicah can be controlled electronically. I need advice on what mechanical system would work. The boat has an outbord motor with the standard control box with the thrust lever. What would be the best way to go? I was thinking of either somehow connecting a shaft and spur gear to the lever which would be controlled by a stepper motor? Another way would be to somehow attach a device at the motor which has a hydraulic system that accelerates and reverses the propeller?
Please Help? Open to suggestions
Thanks

 

You can buy equipment that will allow remote onboard control from manufacturers that specialize in marine control equipment but make sure it has been tested and passed EMC testing. I test marine equipment and found a new onboard remote unit by a reputable manufacturer that could not pass EMC testing. I've heard a story from a tugboat captain that had his boat on auto pilot and went under high tension wires and the thing went nuts. If you used an untested and non-compliant remote unit in such a circumstance you'd probably regret it.
By remote are you wanting onboard remote or radio control from shore?

 

For this application, you need an actuator that will consist of a motor, some form of gearing, and possibly a position transducer (depending on your application). A stepper motor with not give you the force you need AND quick response time.

As Doug hinted, remote controlling a machine that can do a lot of property damage or result in personal injury is serious business and requires a serious approach. If this remote control is to be done from a distance, you need to have fail-safes and various protection measures built in or you become a lawyer's dream case.

 

Throttle and gear shift are the easy part. Look for my contributions in this forum section.
How about steering? That requires more force and quick response time.

And don't you need some kind of feedback like a video camera with zoom and pan function?

 

There are a large number of linear actuators with sufficient feedback to be used as servos. Just search for "linear actuator" or similar on google. The steering could be handled by hydraulics and a rudder-position sensor.

The sort of response speed you need is governed by how you're trying to use the boat, and how big it is. Unfortunately, there is no easy way of calculating turning circles etc. to work out the required response times.

Failsafe is a requirement for this system. I would suggest neutral helm and engine at idle, out of gear as a starting point. Believe it or not, the mechanical control is not the particularly difficult bit. setting up the electronic control mechanism could get very complicated depending on what you wanted it to do.

Tim B.

 

Hi Cdk. Some complicating designs there. I basically need a mechanical system that would need to be monitored electronically. So eg. a shaft can be attached to the lever and would be driven by a motor which in turn would be controlled by the remote control. Basically the boat would be controlled by remote ( speed, steering). GPS and radar would also be present as well as panning cameras. After about 50 m away the boat will become autonomous. The boat will be sent out to sea with no one on it...

 

If you find that complicated you may be biting off more than you can chew.

But there is another, non-technical issue. There are maritime rules and laws.
You may be giving someone an expensive present once a salvage vessel spots it....

 

I would strongly suggest testing your idea at model scale first, to get an idea of the sort of problems you'll encounter. I think you might be surprised.

Tim B.

 

Hello 4186326,

Is this the number on your uniform

I am currently designing an electric steering system for my boat(s). The steering etc are done by electric motors and the on board controls are electric / electronic. Forget steppers, too heavy and not enough torque.

This is the second time I'm making an electric steering system, it's not that difficult. The first time was a bit of an overkill.

The intent is to be able to have the boat auto steer, wind, compass or GPS. Very easy on paper I'm about 50% with the basics, the PCB's & suff are being made, populated and programmed. Looots of work.

 

There are literally thousands of both free-floating and tethered oceanographic data collecting devices in the oceans. There are at least 25 autonomous vehicles, underwater or surface, or running in return-to-surface to 'call-home' mode.

To be legally salvaged, the salvor must believe the object is "In Marine peril" The law (USA) says: "An “[object] is in marine peril if there is a reasonable apprehension that, in the absence of salvage, it will be lost”

If it's running along happily, or stopped displaying a sign that says "Autonomous Marine Vehicle - Not in Peril - Do not approach" I don't think the courts would award salvage..

---( longer quote )---
A. Traditional Salvage
“A salvor of imperiled property on navigable waters
gains a right to compensation from the owner” [6]. AUVs
would be property subject to salvage. Courts will enforce
salvage claims when valuable property in peril is saved on
navigable waters. To receive an award for an act of salvage,
the salvor must have voluntarily undertaken and
successfully rescued property from marine peril. An
“[object] is in marine peril if there is a reasonable
apprehension that, in the absence of salvage, it will be lost”
[7].
---( end)---
From "The Law Governing Autonomous Undersea Vehicles: What an
Operator Needs to Know" -S. E. Showalter
National Sea Grant Law Center, University of Mississippi

--- Terry King (Who just took a couple of Oceanography courses and wants to dunk some electronics in the Red Sea )...

 

Any form of RF remote control is going to be risky. Some of these jap boats have 1500W transmitters (and what else) that would kill anything RF close to it.

What's the remote boat for anyway ? You're going to sail from the comfort and safety of your own home ?

 

Hi Terry, you took "salvage vessel" too seriously. This project is about a fully equipped boat with an outboard engine, heading out to sea with nobody at the helm. It navigates by gps and avoids obstacles with radar. Unless there sits a dummy with sunglasses and a captains cap behind the wheel, it won't take long before it is "salvaged".

In front of my house there is an uninhabited lighthouse island 5 miles out. It has solar panels, cameras and telemetry, protected by large steel doors. I do not know who does it, but there seem to be tourists with crow bars and heavy bolt cutters, because every year it gets "salvaged".

 

Coming from a background of 35 years in engineering, the first step in a project is to define the objective: what do you want to be able to do? And then develop the system to make it possible.

It would be a big help in this thread if we knew what the requirements were and the setting in which this was to take place. An R/C boat used for herding logs in a sawmill pond will be an entirely different fish than one that is supposed to cross the ocean from port to port without a crew.

.... just my thoughts....

 

Re

Hi guys. Thanks for the response.
The boat is going to be use for rescue operations. For eg if someone needs to be rescued and its to risky to go out, we send the boat. It is my design project and it is basically a mechatronic project, since I am studying mechanical eng.
Cdk your design is great but I dont have the time since the mechanical actuation part is due next week. Thats why I most prob will be using a linear actuator to control the throttle lever. I am still working on actuation of the steering wheel. Any suggestions are welcome
thanks

 

It's nice idea, but I think you'll struggle with that brief. Eg. why can't you send a crew? sea-state? Also, how will you effect the rescue when/if you get there? I would suggest that you looked at something smaller, perhaps for a surveying role. This doesn't change what you're conceptually trying to achieve, but might give you an easier question to answer.

Generally in heavy weather, you need someone driving the boat so they can respond properly to the sea-state. Have a chat with your local Coastguard, they'll be able to explain the sort of training they do and the conditions they operate in.

Tim B.