Yet another cheap and easy to build motion platform!

[ak49er]

All this easy DIY has got me thinking of bigger and better. Has anyone considered using an industrial pallet positioner for a good strong motion base, It already has load bearing capabilties, yaw and lift, with two more pivots one could have pitch and roll, surge would be limited but daoble. $.02

[RobiD]

What is an industrial pallet positioner?

[ak49er]

Basically it is a heavy lift frame about 60x60x60", with different load ratings 250-4000#, it has a scissor style lift rack to a pivoting top "base" , so lift and yaw are prebuilt, also it is load neautral so as you "stack boxes on a pallet the stacking height remains the same as the positioner "drops" down. A person could (for 895-3000 USD) add lift cylinders, gear motors, and the such or place a motion base similar to the one described ealrier in this post and have a 4DOF base. Lift, yaw, pitch, roll.Of course this would be overkill for many but might be right for a heavy, enclosed type pit. Not in my realm but an alternate solution for some. I was daydreaming while ordering parts out of the Grainger catalouge.

[AndyT]

Sorry to take so long to answer, I've been busy with the real world lately.

My platform is designed to give me 45 degrees of motion in 2 DOF. That means I get 90 degrees total on pitch and roll. Using the Mercotac slipring I also get unlimited Yaw. Because of this I do not have washouts planned so far.

Since I get 45 degrees, I look at what I'm likely to do in the sim. Since I fly mostly GA planes, I will likely never exceed a 90 degree turn unless I plan on doing some aerobatics. My platform will do half of that so I make each 1 degree on the platform equal 2 degrees in the sim. When my plane is at a 60 degree turn in the sim, the platform is at 30 deg. I don't want to do a washout because I want the sim to hold that 30 degrees as I spin on the unlimited Yaw. This will simulate the centrifical force you feel when in a real plane doing this kind of manuver. When you level out, the platform will level out as well. The only time I need a changeable washout is when I'm doing aerobatics. How do I make it change over to the other side of the platform without flipping me over?

[Jim NZ]

Hi Louis, Just back from Aussie outback (Now I know where flies, dust and heat come from) and caught up with your post.
Brilliant concept and I particulary like the cunning way you have "looped" the chain a couple of times to get the torque and speed right .. It took me a while to work it all out and its real cunning !!! It would keep the profile of the whole thing down as well.
Fully agree with you about the smaller angles required for an enclosed cockpit ,, I found that out real quick when I built mine, but I got to admit, people building "open" cockpits would need more as its a different sensation they are going for.

Welcome to the madhouse Louis .... There are heaps of nuts like us in here !!!
You will know by now, you are on a mission that will truly never be finished ,, always improving !!! I'm building the MK2 platform at the moment but already the MK3 is in my head !!!
Keep us informed with progress.

Jim NZ

[wannabeaflyer]

Hi Jim Glad to see you survived your days in the wilderness LOL just an update for you all ...After serious head bashing major frustration and down right cant get to grips with it ( C'#) i opted to use VB6 based on the sample codes you made available and boy what a difference that made , Basically i was able to write code Change code Try code and see results ( now thats more like it ) Thanks to your lead i am now able to Pull Data from FSX into my Program and Configure strings to send to My KT5198 Controller Card . Had a Weird moment where one PC would allow me to Connect to and communicate with my K8055 USB card But Came up With Error message about needing a License for Comms ( Head scratcher ) and on the other PC Comms Was ok But Usb Error with the K8055 card ( Go Figure ??? ) anyway at the moment i am developing my code on 2 Pc so's i can try & test things as i go along But have to say once again and will shout it "THANKS FOR THE JUMP START JIM" some day i'll get another light bulb moment and the C# stuff will fall into place but for now im just majorly happy that i can move things along agin because Using VB6 allows me to experiment real time Cheers jim and all the rest of the crew for making their code available .. Will post my initial 1st attempts on the FTP site sometime next week when i tidy things up ( Happy days again)

[louisgr]

Jim, although I'm not trying to compete with Australia in terms of flies and dust, I officially invite you in Canada especially in June for a week-end camping. You will discover the real Canadian air force... and it's not our F-18s

Now to more serious things... I find that the slow speed of the motors is still way to fast. My point is that I'm afraid I will feel the platform moving when the washout algorithm kicks in. Now my question to you guys is should I try to fix that now or will the weight of the enclosure (and screens, etc) alleviate this problem. I thought of running the motor at a lower voltage say 8 Volts to fix this.

thanks

Louis

[Spatate]

Hey hey... i should be there... Je devrais y être !!!

[Jim NZ]

Hi Louis,
Pondered this for a couple of days and havent really came up with anything that may help you, there are just so many variables.

Because you will (??) be introducing electronic speed control, its better to be too fast in its present state than at the right speed.

At the end of the day, when you introduce speed control (PWM ???) you hopefully will be able to adjust it to suit.
Dont panic at this stage ,, The platform I am building at the moment, with no cabin or anything on it, was quite "snappy" in test's using 12 volts.
I have now got the cabin etc all built, monitiors etc all in, and I am currently using 20 volts DC thru a KT5198 board and it works lovely.

Just one hint though ,,, you wont be able to have any "null" period of moving when it changes from one direction to the other.You need to have no slack in the chain or when you introduce softstart/softstop, the sensation you are hoping for will be lost. Just a thought ??

Sorry I'm not much help there Louis but keep going on your great work.

Calvin ,,, Pleased that you got the VB6 stuff to work ,, With all the downloads of the source code, your comments have been the only feedback I've had, so its nice to know that it actually works on some-one elses setup. I'm testing the main software at the moment and all seems well except for a couple of wee glitch's. I'm updating my website soon with all this, so keep an eye out on that.


OK .. see ya's .... Jim

[wannabeaflyer]

Hi Jim have to say the difference it makes to be finally have some code that i can work with, really gets the adrenalin flowing again. just seen the latest info on your website, and its brilliant in its simplicity as always with your stuff ( you kinda make things doable ) loved your version of the feedback pot arrangment, I have something drawn up on autocad inventor that i thoght was the bee's kness's but that was based on rotary Pot's the fact you used Inline sliders with a single tensioning spring was a real nice touch and more to the point easy to replace/ Cost effective option ..
Got my code to read FSX data ( your code really i just rehashed bits so that i could learn how you did it so all credit goes to you) and have been able to read the ADC inpiuts from my K8055 card & the KT5198 card control strings can be configured by the front panel for different speed ranges again using your lead . this was alway gonna be my 1st step ( to get control and read info from the Interface cards ) having doen this im now trying to pull it all togather....
one thing i gotta ask regarding the KT5198 when sending speed , acceleration data etc to the card to set the motor parameters did you end up sending each bit as a separtate command one after the other or was there a way to combine all the data into one command string ...example @aa M1SP 200 M1AI 50 CR LF or did you have to do as i am doing at present send @aa M1SP 100 CR LF Follwed By @aa M1AI 50 CR LF etc etc ... I guess now the real fun starts but as always one axis at a time Cheers Jim, im sure you will get more feedback once the guys realise that VB6 is not a bad way to go when starting out Control systems software/hardware link and have to say lessons learnt from tryiong to get to grip's with C# have shown that transferring over to VB.Net may be a good halfway between VB6 and C# ( but thats the next Jump ) just want to get my baby moving again LOL