Using 9x for 4 wheel steer!

Not sure what firmware to use? Making a new firmware? Ask in here!
Post Reply
MadScientist
Posts: 60
Joined: Tue Jan 15, 2013 6:43 am
Country: -

Using 9x for 4 wheel steer!

Post by MadScientist » Tue Jan 15, 2013 7:00 am

Hey guys! Im in a mechanical engineering program, and our project this semester is to convert a off road rc car to 4 wheel steer. I need a little help with the control side of it though. I went ahead and bought a Turnigy 9X and im getting ready to buy the DIY kit from Parke, but Im a little concerned with how Im gonna make this thing work, and how all the mixing will work. Ive never messed with R/C before so Im a total newb.

So I figure I will give you a list of things i need to do, want to do, and what would be nice if possible. and yes i do know it will probably be a little difficult to drive, but im not tryin to win any races.. just pass the class with it functioning correctly. (basically so the school has something to show off)


must dos
-must have 4 different settings for Rear steer
-----opposite front wheels (1:1)
-----Same direction as front wheels (1:1)
-----off
-----Independent control with a different stick


would be nice
- would be nice to have the right stick set up so that it controlled throttle (full down being 0, full up being 100%) AND the front steering, so the basically you can drive the car with one stick.
-if possible, id like for reverse to be selected only when you flip a switch (so then the right stick would be full down = 100% reverse)
-This same setup, when the proper settings are selected should automatically control the rear wheels too
-the left stick (when in independent mode) would control the rear steer by itself


if its possible--

ideally, (if this is possible forget all the above stuff) id like to have this thing set up so that the faster it goes, the less rear steering there is. Id also need to be able to set mixing so that i can get the front/rear to turn the same way if i want. im not sure if thats possible, or what kind of telemetry feedback i would need. But If its doable I figure you guys could direct me on how to do it.

lastly, if its at all possible, id like to go through the menus and replace all the air craft terminology with settings like "rear steer %" or "front steer Mix" or things like that..



SO i got4 months to get this thing done. what can you guys do to help me out!!

THANKS ALOT!


User avatar
Rob Thomson
Site Admin
Posts: 4541
Joined: Tue Dec 27, 2011 11:34 am
Country: United Kingdom
Location: Albury, Guildford
Contact:

Re: Using 9x for 4 wheel steer!

Post by Rob Thomson » Tue Jan 15, 2013 7:26 am

Nothing here sounds impossible.

Just need to make sure you get a custom firmware on it!

Sent from my GT-I9300 using Tapatalk 2
Slope Soaring, FPV, and pretty much anything 'high tech'
...........if you think it should be in the wiki.. ask me for wiki access, then go add it!

MadScientist
Posts: 60
Joined: Tue Jan 15, 2013 6:43 am
Country: -

Re: Using 9x for 4 wheel steer!

Post by MadScientist » Tue Jan 15, 2013 7:29 am

well thats my first priorty, which is why im ordering the smarty parts board. but once i get the er9x firmware loaded up, im completely lost on setting up the remote and the mixing. like i said... NEWBBB. lol.. if you guys are interested, as we go along, ill post pics of the truggy and the work were doing on it to make it 4 wheel steer.

MadScientist
Posts: 60
Joined: Tue Jan 15, 2013 6:43 am
Country: -

Re: Using 9x for 4 wheel steer!

Post by MadScientist » Tue Jan 15, 2013 11:14 pm

ive been thinking about the controls layout, and i think i have come up with a better way to control the car.. but id like some or you guys suggestions first on how it should actually be controlled via the radio. once i figure out exactly how the controls should work, then i can start on the mixing.

MadScientist
Posts: 60
Joined: Tue Jan 15, 2013 6:43 am
Country: -

Re: Using 9x for 4 wheel steer!

Post by MadScientist » Wed Jan 16, 2013 12:24 am

ok fellas, this is what i have come up with. i think this would allow the easiest operation for others, long after our class has disappeared. I feel this method would also eliminate any switching, or other factors that would hinder high speed operation. So if this is feasble, the only thing i would need is instruction on how to start mixing, and if its possible to do the speed feedback to limit steering. (but we will save that for when i get the controller in and the firmware loaded.
Attachments
X9 contol Map.png


tux75at
Posts: 6
Joined: Sat Jan 05, 2013 1:48 pm
Country: -

Re: Using 9x for 4 wheel steer!

Post by tux75at » Fri Jan 18, 2013 6:11 pm

I also new to this, but from a few videos which i saw maybe its possible to mix with switch settings.
I saw somewhere that you could have a channel mixed in a way like that:
left stick horizontal -100% on a switch position
left stick horizontal +100% on another switch postion
I am not sure if mixing like this is only possible on 2 way switches (digital switches?)
You would need to mix with a 3 way switch and could then mix it in a way
50% left stick horizontal +50% on switch position 0 ---- for full steering
50% left stick horizontal -50% on switch position 1 ---- steering off
50% left stick horizontal -150% on switch position 2 --- same direction steering

1 Stick and 1 3 way switch could be enough if its possible.

If you can only use 2 way switches then you can set it up with 2 switches,
in obove way you could make a mixing with either 2 positions for steering off or you could possibly set it up in a way to have 200% steering (4 switch positions with only 3 modes)

I only saw it once how it can be done, and i saw it with just 2 servos moving the same direction with switch mixing between full and half ratio.
I cant even say which firmware it was.
And again i am new to this and thinking which TX i should order (9X or 9XR) but most likely the 9x as of modding possibilities.

Edit:
I just found the video on youtube: https://www.youtube.com/watch?v=gaERMHA_FNM
Its a short intro into mixing, the last mixing where he uses throttle for mixing if you use -50% instead of -100% it might work, but not sure if you would have to add an offset because you dont want 0-100% and 0-50%, you want something like 0%-50% (left) 50%-100%(right) and 25%-50%/50%-75% for half steering, the reverse might work, as you could choose -200% on the switch, then it should be reversed, hopefully the middle position stays in middle position then.

tux75at
Posts: 6
Joined: Sat Jan 05, 2013 1:48 pm
Country: -

Re: Using 9x for 4 wheel steer!

Post by tux75at » Sat Jan 19, 2013 8:11 am

The mixing which you showed on your picture looks like impossible.
The only way to implement this, is using a microcontroller (e.g. atmega) use the 4 channels as inputs and calculate the new outputs.
There you have no limitation to mixing as you can write your own mixing in C-code.

User avatar
Kilrah
Posts: 9989
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Using 9x for 4 wheel steer!

Post by Kilrah » Sat Jan 19, 2013 9:24 am

I'd say the opposite. Doesn't look like it would be a problem to do at all. Have a look at the custom switches to create zones that are active given a set of conditions.

User avatar
gohsthb
Posts: 1412
Joined: Wed Dec 28, 2011 2:32 pm
Country: -
Location: Naperville, IL

Re: Using 9x for 4 wheel steer!

Post by gohsthb » Sat Jan 19, 2013 12:29 pm

There is another post, he already has this done.
viewtopic.php?t=2567
4 wheel steer with 9x
-Gohst

Sent from my LG-P999 using Tapatalk 2

MadScientist
Posts: 60
Joined: Tue Jan 15, 2013 6:43 am
Country: -

Re: Using 9x for 4 wheel steer!

Post by MadScientist » Wed Jan 23, 2013 3:32 am

thanks gohst, i forgot to post in here that i was moving the conversation over there. and yes, for anyone wondering i did get the mixing done. i wasnt to complicated once i learn the software. still a couple things id like to do, but im at the limit of the firmware. you can download my mix if you want. pretty soon, im going to try to create another mix for rock crawling that will give those guys a ton more control and allow them to do digs and what not.


Post Reply

Return to “other”