wannabeaflyers 6 DOF with 24V DC gearmotor

FYI, I investigated using optical encoders for my actuators, but they can be quite demanding processor wise on the Arduino for reliable operation (no missing pulses ), or you could design and build a circuit for a quadrature encoder chip. You then will likely have to setup some end stop micro switches and write code so that the system can 'home' itself when it initialises. I ended up keeping it simple and just used good quality pots and end stop micro switches to stop the actuator possibly damaging itself due to a feedback hardware failure. Just remember to place a tantalum capacitor between the feeback line (where it connects to the arduino/controller) and earth, to remove the majority of any picked up noise. This noise if not removed, can make the motors 'buzz/click/vibrate' when they are powered but stationary.

Hi seattime thanks for the tip all greatly appreciated, i have a small understating of how the system is intended to work but a lot and I mean a lot to learn, thats really part of the fun of taking on this project , so bear with me if again I may have missed something.
With this new configuration was going to try the optical encoders directly connected to the quadrature input of the kangeroo card, in this 6DOF system I wont be using the arduino. In my 2dof system I will do as you suggested and keep it simple ardunio uno , sabertooth 2x60 will try yhe hall sensors but probely use the good quality pots, and server psu, wanngians 2dof code looks favorite as it drives the sabertooth , all in all its a learning curve and with some pain I hope to make big gains lol.. hang with me guys and ill keep you updated as to my success and failures ..

For the people who like pictures in regard to using capacitors for feedback signal filtering. This is with everything wired up and running with 24VDC power supplied to the motor.



Note: I'm still using ribbon and not screen cable for my feedback line. Will change over to screen cable when the actuator is installed in the rig.

Hi Seatime mega thanks for this info, yep im one o those pictures speaks a thousand word guys , so it was great to see this visulisation of the noise picked up by the sensor , gonna try to have a go at the 2DOF electronic setup today using pots , while I wait to see if Ian at BFF simulation can offer any advice as well, sent a ticket to the dimension engineering guys so fingers crossed between them and you guys here I'll get this solved. Cheers Seatime

well the saga continues im sure this is not right . due to the issue I have ( self infilited maybe ) but I decided to go back to the basics operation for the sabertooth , I removed the kangaroo card and reset the dip switches for analogue input , with the pot output set to pin S1 on the sabertooth 2x25 controller checked wiring and powered it up Both motors are connected so I figre the one without pot input will run at whatever speed due to no feedback, so 1st thing I noticed was that when I adjusted the pot the motor on channel 1 operated as it should and foolowed the pot settings, the motor on channel 2 just ran due to no feedback , so far so good ,

Next test was to swap the Pot input to S2 ref control Motor on Channel 2 ,,Hmmmmmmm When powered up again I expected the Motor without Pot input to Run I,e without feedback and the Motor on channel to to respond to Pot Settings as it did on the 1st test .. well what I saw was the Pot signal to S2 seemed to drive both motors as though the signal was shorted to S1.... ?????? in effect the motor position of Channel 2 was now mirrored on channel 1 ??? I am putting a video on youtube but uploads are soooooo slooooww ,,so will add the link when its up :-(

youtube link as promised, in this test the pot is connected to S2 and should I belive only control motor on channel 2 , I expected motor on channel one to free wheel not to be influenced by the pot controlling channel 2 , the dip switches are set as defined by dip switch wizard and independent mode, not mixed

it is known that if you don't have any pot connected to feedback line will have some strange behaviour on motors as you described above
what happens if you connect the second pot on the circuit?

Hi InsaneGr sent dimension engineering a ticket over this but will now try your advice , i got caught up in the fact that channel 1 does not show any cross talk with channel 2 as it were, and with the pot on Channel 1 it only controls Thechannel 1 motor ,however if i do the same test this time with the pot on S2 Channel 2 then the madness Occurs .. will grab another pot and repeat the test . Thanks for the tip . will keep ya posted .. Cheers

@wannabeaflyer2, there is no reason to concern yourself about conditions that won’t exist in real life. In real life you won’t be connecting a motor to a channel on your kangaroo without it having a feedback device attached to that channel too.

As insanegr stated, usually pins on electronics that are not connected when they are expected to be will cause a “floating” condition. The pin neither has a voltage on it nor is it grounded, so the pins state is in limbo, it is not stable, and strange things can happen.

Also, while noise from standard analog pots can be an issue, there is no noise from hall effect pots because they are digital (unless the noise is getting in from elsewhere). Therefore, I don’t believe the problem with the kangaroos auto-tuning has to do with noise when it comes to using hall pots, but I could be mistaken.

Hi Guys once again thanks for all the encouragement and tips, at the end of the day this will boil down to a mistake i made i'm sure , i love the Dimension engineering stuff, just a case of connecting things correctly ,
I have sent a ticket to the guys at DE, so post their response here for Others to learn from my mistake.

The Auto tune thing is something that needs more Info on my part, im aware that if you go past the Min - Max Sensor range then the Autotune will be Void or if the difference between all 6 Actuator varies by > 0.2V , its just that i find in Describe, that once you select the channel to be tuned and then trying to move the the Cursor in the tuning window via mouse-pad On my laptop, to position the Actuator, means it often overshoots at the last bit while trying to stay within the 0.2 - 4.4 V range that my Sensor has, Now this could be a part if not the reason i'm struggling , is there a trick i'm missing when it comes to auto tuning ??

Thanks BlazingH and InsaneGr . did not get some playtime yesterday but will keep you guys posted as to whatever developments occur Massive thanks Guys .. Hang in there with me , it will all come good in the end ( finger crossed )

One tip I got from DE was to try tuning with a reduced range of the pots if you are having problems completing an auto tune. After tuning you can then use Describe to manually change the min-max limits to increase the range. Also, if your setup allows you to, you can manually move the pots to their min and max positions before you start the tuning process.

Another thing, 4.4v on your pots on the high side is low. They should go to around 4.8v. Normally I would think you aren’t getting a full 5v to the pots Vcc but since you are using a kangaroo, and it draws power from a 1amp BEC on the sabertooth, I don’t think that should be an issue in your case.

Hi BlazingH your a star sir finally got to the man cave this evening and connected 2 Pots one to Each S1 & S2 line and exactly as you and InsaneGr stated the Controller worked as i believe it should do, so i was able to control both motors independently of each other without any apparent cross talk...Yeeee Haaaa Baby my controllers are still good to Go it seems ( Phew) ..
it seems the Floating input was indeed creating havoc , Strange that this was not the case when the signal was applied to S1 ?? but such is life ( in the electronics world ) ..

In the meantime i Built up a a test setup for my Boys 2DOF Sim Just need to Connect the Pots to the Actuator Shaft ( using Gears to get better resolution from the 10 Turn 10K Pots i'm using for testing) .. Still waiting for the encoders , so once again guys sincere thanks for all the patience and tips ( they may rattle around in the old grey matter) but every now and then a EUREKA moment occurs and all is well LOL

Just a few rough and ready shots of this evening efforts , This lash up ( Arduino Uno / Sabertooth 2x60 / Wanegain or Racing mats Software ) is just so i can play with Simtools and try to get familiar with its operation and hopefully communicate with it and the Motors ...this weekend will be Blitz the 2DOF Platform ( Getting an ear Bashing from my boy (not an easy thing for a deaf Bloke to complain about LOL ) but having told him my plans he's expecting great things LOL ( me thinks i should of kept quiet Software loaded and OK on the Ardunio & Temp wiring looks sound so Simtools , Here i come .. (more reading at bed time)

Hi Guys just a small progress update and big thank you to @BlazinH for the tip regarding kangeroo autotune process , and as i mentioned before it would turn out to be a pronl;em of my own making , Well it seem like i got got a kind of loop over the whole tuning process in so far as every time i did an autotune i was overwritting the information in the kangeroo and in effect blanking the tuning data and convinced myself it was a duff controller ( yeah i know dammmmm foooool Man) anyways i had hours of messing about checking wiring baud rates swapping USB converters etc then had a moment of clarity ( go read the bloody manual again LOL ) upshot being my mindset was after autotuning and rebooting the cards dont press "Upload to Device " button Thats not how it works LOL it should be the "Connect and download to Describe" i cant explain why it took so long for that to drop into place ( Duffusss comes to mind ) still thanks to BlazinH's advice and the fact i can disengage the Gearbox drive on the motor , i was able to use the DVM and Manually set sensor Min & max values before continuing with the Autotune process , and have to say it was great and it worked a treat for all 6 axisis ...Mega relief ..Early days yet but hopefully it appears the violent juddering is was seeing was a reaction to crappy autotuning on my behalf.. so once again the dimension engineering products came good and protected themselves from this Idiot LOL..
Mind you i was able to finish my 2 DOF bench test mockup and managed to get it talking to simtools as well as manually being able to check out axis/ Actuator for Motion & direction , think i need screened cable and the capacitors mod to lose some noise but all good stuff build that had its problems but in the end the Problem was Me ( Note to self , check check and then check again if its wrong ya didnt follow the instruction properly ) ...Cheers Guys

some pics and new 24V server PSU with DC isolation mods Not the AC side Isolation

Another Update that shows some promise , OK once again the weak link in the chain turns out to be you know who, With the help and clarification from Ian at Buggies Built for fun I am now able to communicate with FSX , Sabertooth Controllers and The BFF software ,,

Good news n make that Great News, is I can once again see the actuators ( all 6 This time ) being controlled by data from FSX and manually via BFF 6 DOF software ,, So am taking a day off tomorrow to have a major attempt at getting the platform properly autotuned and fitting the limit switches etc before adding the top platform to the motors... will get some clips for you tube , it may not be pretty at this stage but it was always about learning about the whole package and seeing if my 1st design came close enough to at least prove It can be done..
Ordered some More 180 Degree hall sensors for the 2 DOF so that should get rid of the noisy signal,, best news is that during my faffing about I have learnt a lot about both Simtools and BFF ,,,,,, Buckets more to figure out but the foundation is in place for both project... Feeling a little happier today ... so once again guys Thanks for all / any input its all been good stuff .. will post pictures asap after tomorrows Project Blitz day

Happy as Larry as they say , My frankenstien Creation lives i tell you , she lives LOL
All's well after some assembly work earlier today , the beast kicked into life , NO Smoke , No Mechanical Cries of Pain , good software hardware comms, so even though it looks like the pigs dinner at the moment , it seems to be doing what it should when it should and big bonus is the Autotune seems to be Holding steady ( famous last words) at the moment, had a few short flights or should that be controlled crashes in FS and shows all seem Good so far, Also with the DVM i may well be able to reduce the actuator arm travel in the autotune range to keep within the recommended 170 degrees movement angle, but the video im uploading to "Youtube" will confirm i need to reduce it a wee bit , Now gonna mess with adding Limit switches and rehousing the electronics in a DIY enclosure .. Catch ya soon guys said it before and will say it again Thanks Guys

Video upload guys, Ignore the background bits n bobs, so many project so small a space LOL . Ok the video shows me setting up one channel for Kangeroo Autotune Using a DVM to determine the MIN MAX Set-points Before Setting it back to 2.5V then pressing continue in the describe Program to start the Autotune sequence . Make sure its all bolted up cos that Process Shake the axis to Buggery LOL

Hi Guys , Work progressing nicely on both sims 2 DOf and The 6 DOF, will start a new thread for the 2 DOF soon so these will be the last pictures of the 2 DOF Prototype , Really just happy over that fact that at last I have built them and so far other than teething troubles of my own making things have gone well, Both sims have mechanical and Software up and running and no major design issues and seeing as the 2 DOF really was made on the fly with material I had lying around ( collected over the years but never used) its not too bad for the mk1 version .. The 2 DOF still needs fleshing out but it seems to work . Slight judder sometimes around the Mid Point travel of the actuator, but I think that's gearbox backlash so maybe I vary the deadzone setting to cure that ..( ps I had 180° Hall sensor pots fitted )
Busy day today but was able to get it running so tomorrow will be weight testing And seat Fitting .. Lots learnt and now having seen some other sims I believe I can change things for the better and make it with fewer Pieces watch the new Space LOL.. Will draw up the design on cad once im happy and share for all who may be interested Cheers Guys Not Done any Current Drawn (Supply PSU / Battery Amps ) tests yet and that should be nice info, seeing as these motors are the same as the ones on the 6DOF, Took delivery of nice little E bay Ampmeter module and shunt to be wired in First though , I know this is going to be a balanced rig so even though the results may differ some info is better than none, Again i'll post the results in the next post ..