Motors and stuff...

[kranky]

So I've figured (conservatively) the approximate weights of the platform.

Fuselage w/ seat 260 lbs
Pilot 250 lbs
Platform 100 lbs
Controls (w/ radio stack) 74 lbs

This comes to 684 lbs (310 kg). I'm planning a 3 DOF system, meaning each actuator supports ~105 kg. Assuming a 2.5 in. arm (5 in heave), that means I need 580 in-lbs (66 N-m) of torque!!

Now i'm not trying to reinvent the wheel. I like this design and at least at this point will be trying to immitate it.


Now the spring will help bring this requirement down a little, but not much. So I'm looking into motors. Does anyone have any good places to buy motors from? Or have any suggestions for using an old motor out of something? We have money to spend, but of course it's always nice to save when we can.

I still need to do more calculations so I can find exactly the performance specs I want. However is a 5" heave good enough to give the sensation? The pitch/roll will be 25°, but unless i'm forgetting something, that's controlled on where the motors are mounted offset from the centerline.

I'm also looking for advice on the power requirements to run 3 of these. Unfortunately, electrical is my weakness. I need to figure out the room's power requirements. The University has said they'd be willing to help remodel accordingly to supply adequate power. Is DC or AC a better/easier way to go?

I'm open to any ideas, comments, suggestions?

Kranky

[Trevor Hale]

Ac is the best route, because it is readily available. I would stay with 120V single phase motors if you can. (keeps costs down) By the way. 5" of heave is more then enough. 5" at the reference datum = like a foot 6 feet each way. I would think that is more then enough to provide the sensations your looking for. Your biggest trick is going to be the controller that will smooth the start and stop of the motor's.

You don't want to launch anyone out of their seats and I would imagine you will be running CHComm to control the movements from Flightsim.

Good luck, I can't wait to see your progress.

Trev

[kranky]

Yea. I guess what i meant was a 2.5" heave then. It is 5" total travel from top to bottom. Forgot it will be "heaving" from the neutral position.

OK, so the only reason I had 2.5" was to lower the torque requirements of the motor. I will run the numbers with a 4" arm on the motor and see what it does. I'm concerned about finding a motor that will have this amount of torque and operate with the speed and control needed.

I hopefully would like to stick to AC single phase too if I can. Although, I think modifications to where we're putting it will need to be made anyways so that we are on a separate circuit. All things I need to check into.

[Jim NZ]

Hi Kranky,
Chcomm is only good for fs2004 and for a motion platform like you are planning, it would be a bit slow.
Roland, Keith and Thanos have a faster program called portdrv but that also is only for fs2004.

If you are talking about FSX, and if you are talking about having a second "motion control computer" then last week, I finally got a trial program going that will send out, via the serial port, just about anything that simconnect will collect, all at framerate speed. (ie at 30 FPS, thats 33 milliseconds)

I am not developing it really to send this guff out the serial port but if there is interest, I will release a version to do so. It will be a few months before I get this "settled", so probably by then, some other program will be available. All my stuff is freeware.

Hope this helps and good luck on the mission !!!!! Looks great.


Jim

[kranky]

How do you mean ChComm is only good for fs2004.

You are correct, i am using FSX. I was able to successfully extract the data using the instructions on your page using FSUIPC4 and ChComm.

I haven't tried Portdrvr.

I'd be very interested in that trial program when you get it "settled." If it doesn't send via serial, then HOW? USB? Does it send at all? Or are you developing it to be on the same PC as FSX?

What are people using to interface from FSX to control motion platforms? I guess all the articles I've read were pre-FSX. I guess I'm still unsure as to what program talks to who, to get the data?

Simconnect? FSUIPC? Ideally I want to have a 2nd computer to do all the controlling of the platform. However, is that practical now with FSX? I guess I'm open to advice.

[Jim NZ]

Hi Kranky,
My mistake, forgot that chcomm goes thru fsuipc !!!! Yes it would work,, Sorrry (Had spent a bit of time on a slant of chcomm that didnt go thru fsuipc and that seemed to have stuck in my brain.

My mission (if you can call it that) is to develope a system for motion builders that are not electrical/ electronic/ software guru's and is based on, put my software into the FSX computer, buy a cheap kitset board, hook up the board to the motors/ rams or whatever and your away. It is not software for the high end users but I suppose it could be trialed on that.

So, the software (Im going to call it JimCom) is resident in the FSX computer and it outs to serial and/or USB to suit the board(s) I finally choose to run.
There will be no need for a separate motion control computer although, for adaptability, a motion control computer would be benificial for more advanced systems. The biggest hassel was to get the data out of FSX, which I now have done.

At the rate I can get the data out of FSX, it is a **** of a lot of data to send as 'raw data' so it would have been best to "pre-process" the data before going out the serial port. .. at the end of the day, if I were to pre-process the data, I might as well process the whole lot on the FSX computer and do away with the motion computer all together. .. Just my thoughts.

The way to go for high end designers is to use simconnect direct and make their own program to suit.

Anyway, I've opened my mouth a bit wide here so I hope what I plan actually takes shape !!!!! Time will tell. !!!!

At the moment there doesnt seem to be much out there that fits into the "keep it cheap and simple" catagory.

Hope this explains where I am going but I hope others come out with something too. ... Not much point in re-inventing the wheel !!

See ya's .. Jim

[kranky]

So what I'm hearing, is that I have a lot more work ahead of me. I figured extracting the data from FSX was done. I haven't gotten to the point of realizing that the rate of extraction isn't fast enough.

Time to roll up the sleeves...

[Jim NZ]

Kranky...
Chcomm is quite workable at about 200 milliseconds and in reality it is a quick "get it going" sort of system. There is a slight delay in what you see on the screen and what you feel. It never worried me in particular and after a wee while you never even noticed it in general flying. Your brain seemed to allow for it. BUT I was flying GA aircraft and not "shoot em up" sort of stuff.

The fact remains, any "hooking out of data" will have a delay in it because the action is already on the screen before you feel the effect. (I'm talking milliseconds here)
How much this worries the end user is a matter of opinion so everyone see's this problem a different way, but obviously the less delay the better.

With the platform drive you indicated of copying, I assumed it would be a "high end" type of project and have position feedback etc etc

Good luck with the mission and don't yet write off chcomm if it will get you started sooner !!!! You can always improve on things once you are actually moving.
Building a motion platform is a long process with many things that need to come together at the end. .. Thats when the real fun starts.
Also by the time you build the hardware, there will be (hopefully) quite a few programs you could chose from for data extraction and processing.

OK leave you with that thought ....
see ya .. Jim

[kranky]

OK, well at this point I plan on just doing GA aircraft for that reason. I want to keep it at least a little bit simple at first.

This is not only my hobby, but I'm doing it for school as my final Senior design project. The good thing is, I'll have a team of people who are working on this. I'm currently recruiting electrical, mechanical engineers and Computer science majors. It's a decent sized project so there's enough work to go around. Given this, I set a completion goal of December 1st. Hopefully that's not too optimistic.

[wannabeaflyer]

Hi Jim Just thought i'd jump in here and add to what you have said CHcomm realy does allow you to get up and running quickly and cheaply in terms of motion . i am learing so much about the mechanlical starins and elements now that the platform is built and running. over engineer verything then streamline seems to be the way. will keep my eye on your latest efforts as you never do things by half measures but never seem to lose sight of the fact that you are making it easier for a lot of us out here to get into motion simming , Got FSX 10 last october and its still in its wrapper Scared of activation errors and need PC update so want to make sure it goes with my next pc .. Seen some stuff on Simmconnect so will see how that goes .. My only beef with my set up now is the fine point between motor control for flight movements and Return to center ( the dreaded Bump on Return LOL but loving every new bit added ( projector & 2 LCD monitor for Panels end PSOne screen for GPS coming soon ) PS solution to my weak motors seemed to be Duff Car Batteries for 12Volt supply switched to 24V power and this Baby moves great Big Smile Big Smile .. who wouyld have thought wiper motors could shift my lardie butt around so well LOL Great stuff Jim