Full Motion Simulator

[Guest RichardL]

Interesting find.http://www.noonco.com/flyer/

[Guest PeterK]

PeterK Pretty ugly toy....reminds me of somthing from Dr Who...I also couldnt find a price? Also CFS1 was used as a demo program...But still and interesting little box..thanks for the info...peter

[Guest]

If you think that is ugly, take a look at the pic below: It is my attempt at building a simple and cheap motion platform for GA aircraft. Not something you want to put in your living room. ;)Still, it is very interesting to see how far you can go with limited means. (I haven't hit the 200 dollar mark yet). The whole thing is suspended in cables, for making pitch and roll over +/- 30 degrees. It is big (& strong) enough to hold my DIY GA cockpit controls, and possibly multi monitors. Electrically driven, the power servo system is finally working now. (To tell you the truth, the forces can be somewhat scary). Now still got to experiment how to drive the 2 axis from the PC. Something to keep me busy. :-) Roland

[Guest MikePowell]

Pretty interesting, Roland,How do you have the suspension arranged? I recall reading some time ago about a student project that used an inverted Stewart arrangement with cables. Sort of an upside down version of the hydraulic system used in commercial simulators, but with six cables in tension replacing the six hydraulic rams in compression. I think the student system suspended only the seat and basic controls. Are you doing something similar?I share your views on the forces involved. They rapidly move to large numbers when quick response is pursued. What sort and size of motors are you using and what system frequency response and slew rates do you see?I'm impressed.Mikewww.mikesflightdeck.com

[Guest]

Hi Mike, Below pic and drawing may explain a little more on the suspension system, and the cable drive.The motors I used are industry type DC, rated 60V 6A. I got them from the junk, leftovers from old production lines. I guess car starter motors would work as well, if the stator winding is connected correctly. They are driven from a 18kHz PWM half-bridge configuration, with four 12V batteries to make a +/- 24V supply. Originally planned to go for +/- 36V, but the forces got too scary. Position feedback via multiturn pots connected to the cable movements. I did not do much system frequency calculations (a little over my head), but just tweaked the gain until the response looks good. Right now around 0.4 sec from -30 to + 30 degrees, with nice starts and stops. That is fast enough to make the floor shake. Hope my monitor will survive. I spend some effort to include some safety features, you don't want this system to run over the end-stops due to shorted FETs or so. The final (and most challenging part) is putting the right cues to the axis to get a realistic feeling. I know it is very limited with only roll and pitch, but it's still a lot of fun. Roland

[Guest PeterK]

PeterKWOW..Looks more like a time machine.....!Well that explains were all the rack shelving went...!Hows it feel for motion??? Avoiding your sourounding when you get into a game and you are focused into the monitor How does it feel....That Planetarium feel...You know does it move andreally feel like the sim is moving with you...I like it ...It has alot of engineering put into it...pete

[Guest]

I haven't got to the part yet where I have linked the platform to the sim. You are right, it needs a covering to keep you focused on the screen, not the room. I did some tests: The climbing and descending feel is pretty good when tilting up or down. Still got to add some seatbelts, as you fall out of your chair when adding roll. The whole movement needs a lot of experimenting. That's the good thing about electric drive, it is very flexible in input tweaking. I have a breadboard on the platform now, and checking the possibilities of passive & active filters, with sort of correct washout (back to center). Some possibilities of interface:- Direct from the yoke, throttle, brake (I'm using dual potmeters, and then it is easy to take a differential signal from the control input)- cue signals taken from force feedback yoke signals (landings)- Extracting data from FS2002. (high tech approach)The latter has to wait as I'm still using Flight Unlimited III on a P200MMX. (I know, I should upgrade) Roland

[Guest]

Roland,If you go to www.ferrettronics.com you will find what you need to give your system the whole movement.The chip FT 639 and a soft extracting bank and pitch from FS2K2 and the RC servos correctly installed will give you a perfect movement matching with what you are seeing in the screen.RgdsAlberto Kunzel

[Guest]

Alberto, Thanks for the link. It does seem a quick way to get from PC software to movement. Actually the output I'm looking for is more or less an anologue DC voltage that varies with the flight parameter in a smooth and timely way. There are lot's of options here, most of them D/A chips that can be driven from the parallel or series port. At work we use mostly I2C protocol for chip communication, and then a simple chip like TDA8444 could provide 6-bit DACs for up to 8 different flight parameters to play with. It's the software part I have some problem with, as I'm a hardware guy. But I'm getting ahead of things. Nice to see that there are other people playing with these ideas as well. Roland

[Guest MikePowell]

Roland,Here are a few references that may be of interest to you. Although I would not be surprised to find that you are far beyond need for additional reference material. You have apparently already put a great deal of thought into your project.Perhaps the best is a phD thesis by Sjirk Holger Koekebakker at the University of Delft, the Netherlands called "Model based control of a flight simulator motion system". While the more involved technical content is a challenge to follow (it's certainly beyond the meager remnants of my math abilities), the thesis has a comprehensive overview of simulation motion systems, and follows up with an extensive list of references. At one point the thesis was available as a PDF download. However, the web site has been updated and I have not been able to locate the thesis. It is listed in the Delft library and can perhaps be borrowed or a copy ordered.A second document is "Guide to the Motionbase motion cueing algorithms". This is an overview of their proprietary algorithms and is something of a sales document for the technically minded potential customer. Still, it does provide some information of more general interest. This also had been available as a PDF download. Motionbase (www.motionbase.com ) has been acquired and will be changing its name to cueSim shortly. The Motionbase/cueSim website is undergoing changes and (of course) this document no longer seems to be on line. Possibly it can be obtained by contacting the company.A third reference is the book "Flight Simulation" by Rolfe and Staples. This is rather dated (1986), but the physics of motion is the same now as it was when the book was new, and it doesn't hurt that desk top PCs are a hundred times more powerful than the specialized simulation computers referred to by the authors. Following my apparent desire to recommend only hard to get reference materials, I will admit that this book is out of print. My only defense is to say that it was out of print when I got my (used) copy from Powell's Books www.powells.com .Best of luck on your project, and please keep us up to date on progress.Regards,Mikewww.mikesflightdeck.com

[Guest]

Hi Mike, The web has been indeed a valuable source of information on motion platforms. I read the Delft University papers, but as you say it is rather heavy reading. Web info seems to come and go, but there is still some good general info in these links: http://vr.isdale.com/MotionLinks_VRNews.html (many old links)http://www.webcom.com/sknkwrks/flightsm.htm Now that's my kind of teacher!http://www.simpits.org/ had a good article from Justin Messenger, but can'rt seem to locate it just now. Anyway, when my project is more or less finalized I'll do a small write-up for the library.Roland

[Guest MikePowell]

A lot of good links there, Roland. I had not seen the skunkworks one. Thanks,Mikewww.mikesflightdeck.com

[Guest]

GentlemenI think this might be the link you are looking for:http://www.ocp.tudelft.nl/sr/Downloads/the...kker/thesis.pdf(Isn't it amazing the stuff this hobby encourages one to keep!!)Hope it helpsDave T

[Guest MikePowell]

That looks like the one! Thanks, Dave.Regards,Mikewww.mikesflightdeck.com

[Guest PeterK]

PeterK Roland,,,,Maybe mounting a car seat like out of a VW or asian marketcar and buckling in when you run the simulator will get that over steer problem under control...that seat look a bit un comfortableLooking at the pictures she looks like a fighter plane skin would workpretty good and maybe a bed sheet aluminated with a blue light couldgive it a sky effect..pete