How to directly control a jrk12v12?

Hi all,

This is my first post and I unfortunately I'm probably starting with a stupid question. I've been lurking for quite a while and have learnt heaps from this fantastic site. Sincere thanks to everyone involved because it really is a fantastic resource. I've tried searching these forums, the pololu site and google but I haven't found an answer to my question - probably because it's something that nobody in their right mind would want to do, or, maybe it's something that is done all the time but I don't know what to type into the search bar?

I want to know whether it is possible to control the jrk12v12 directly with a potentiometer or joystick to co-ordinate a motion platform? I know that the jrk's have "0–5 V analog voltage interface for direct connection to potentiometers and analog joysticks" but reading the manual it would seem these just make the motors go faster or slower. I can't see how they would co-ordinate the platform.

My plan is ultimately a 2dof motion platform based on two jrk12v12s into worm motors along the lines of ...

http://www.xsimulator.net/community/threads/diy-2dof-simulator.4793/

I'm reasonable at welding and building computers (screwing the bits into place), so the physical parts of the project should be sorted, but I have no idea about programming or electronics. Thankfully because of the hard work of a lot of people I reckon I'll be able to stumble through these parts of the project by following instructions.

The problem is that, right now I don't want it set up as the full simulator but just as a platform that moves with the movement of a joystick - push forward and the platform goes forward, turn right and it goes right etc. I know this is not a great idea but I have a good reason for wanting to start with this design rather than the full setup ... and I'm happy to explain the long and boring story to anyone who is interested. I'm also aware of the Joyrider type of setup ... but I want to convert this to a full 2dof simulator down the track.

So what I'll have is the platform built, the motors, batteries, feedback pots and jrks in place and the jrks running into a basic computer running the jrk drivers and software. What I won't have is a second, networked computer running programs for the jrk software to read and pass on to the motors - this will be added at a later date. What I want is a joystick (or two potentiometers that I can attach to a rudimentary flight stick) to drive the platform's movements.

Can the above goal be achieved through the 0-5V analogue voltage input to the 2 jrks? Or can I get the jrk software to read the input from a joystick plugged into the computer? Would this require extra software?

I would be extremely grateful if anyone can explain a solution (in fairly simple language as I get lost pretty quickly when people begin discussing electronics) or even point me towards a link.

Regards,
Thurston

This possible but the motion would be real bad compared but everyone too themselves, we all like something different.
You could write a simple app to read the joystick and send a signal to the Jrk to move but this requires VB or C knowledge.
In turn the Jrk can run from RC commands too, I know this is useable for position control, as this was the first way I discovered I could use the driver for XSIM with an RC Controller in between.

Be simpler just to use SimTools, or is the game you need it for not supported by SimTools ?
More info before I go further, thanks.

Hi earobbie,

Thanks for the reply. I guess the whole boring story is required ...

The idea about building a simulator was sparked by my wife deciding it was time I built my kids a cubby house. The oldest kid was into boats and so he wanted a boat cubby house. The attached picture (apologies, I know it's not a cubby house forum) is what I built over the next few weekends.



Anyway, after it was finished the kids were delighted for a few hours. Then he announced that he doesn't like boats anymore and is now really into aeroplanes. "Can you turn it into an plane for me". So, yes, I beat him.

Anyway, I've always liked planes as well and his comment got me wondering about how hard it would be to build a flight simulator. During the research I read about motion platforms and figured there was no reason I couldn't build one of those for myself. The problem is that the child who is fascinated with planes is far too young to operate a PC simulator program - and I don't want him pestering me to operate the computer for him all the time. So I want to build the beginning of the motion platform - I'll have the platform sitting in place on top of the uv joint and hooked up the motors, feedback pots, jrks, simple PC running jrk software and batteries. Ultimately, the gaming PC will be networked into this system to create the simulator for myself (and the kids can use it when they're older) but for the moment I'm wondering whether that platform can be operated independant of a game.

Instead, in the short term, a TV will sit in front of the platform playing "pilot's eye" videos from youtube. There'll be a pretend cockpit with a pretend joystick that the kids can push around to pretend they are flying the TV. I'm sure that will be fun enough but I've been thinking that they will be sitting on top of a potentially-working motion platform and so I'm wondering if there is a simple way for their pretend joystick to actually control the platform (i.e. sticking a couple of pots onto it or using a PC joystick). It doesn't matter how responsive the platform is or whether it does what it happening on the screen. This will all be sorted out when the gaming PC is introduced. For now it would purely be for novelty value.

And, given it's for novelty, having to learn how to program anything probably puts it into the 'too hard basket'. I was hoping it would be as simple as hooking up the jrk to a couple of pots on the flight yoke or plugging a joystick into the PC and the jrk software recognises it. Or, as a last resort, another program recognising the joystick and passing on the info to the jrk software. It sounds like my initial suspicion was correct - this is a stupid idea that nobody has ever wanted to do before ...

Regards,
Thurston

Nice story! Thanks

It reminds me a "simple" simulator without motors, only moved by the weight of the pilot and effort on the fixed joystick!
It was a commercial product: maybe someone has the URL as I cannot find it again at the moment :-(

Hi Mat,

Thanks for the reply. I don't want to put words into your mouth but it sounds like you're talking about something similar to the Joyrider idea? www.acesim.com/main.html

I really don't want to build a totally different sim - the motivation is ultimately to build the 2dof platform hooked to a gaming PC for myself.

I was really hoping there was a really simple solution for moving the platform around independent of a game. It seems like there may not be ...

Cheers,
Thurston

Not easily done with the JRKs but I am pretty sure it is doable with an Arduino and other motor drivers. I know there are Arduino codes that use potentiometers to control servos so why not motor drivers?

As a matter of fact, this guy on Youtube seems to have done it:

Hi
not a jrk expert but if you use an rc transmitter / receiver connected direct to the jrk, that will give you the joystick and the mixing in the transmitter if required. you can pickup a cheap tx/rx combo from Hobbyking USA.

A dimension engineering kagaroo / sabertooth combo, has analog pot, rc, or usb/ttl input

regards Terry

Many thanks Historiker and Terry!

It sounds like all might not be lost. Will look into those options.

Regards,
Thurston

No, it is a "simple" seat in equilibrium which moves under body movement: no motors... That could be a neat toy!

Sorry I haven't still found back the link...

If you know anything about Jrks this is quiet easy to achieve.

@RacingMat; www.mydreamflyer.com i think.
regards Ad

Exactly: thanks @adgun

Actually I saw a competitor model (which looks like a A2 atomic seat) but this one shows what I wanted to say!

Hi all,

Just a quick thanks to everyone who replied. It looks like there may be a solution and work is now under way. Will post the pictures and story once we get it up and running.

Cheers,
Thurston.