From 2 DOF to 3 DOF flight sim motion rig

Hi everyone again. This time I gonna show you my new build. Starting from my last motion rig (https://www.xsimulator.net/community/threads/2-dof-flight-sim.18232/) I switched to a 3DOF rig modifiying the whole project.

First of all, the materials I used:

Electric-Electronics

• 3 x 750W - 95Nm - 60rpm motors
• 2 Sabertooth 2x60 (after discard the supposedly 100A chinese boards) (https://www.xsimulator.net/community/threads/reasonably-priced-100a-motor-controllers.17638/)
• 3 x 1200W Power supply
• Two 95Ah 12V car batteries in series to get 24V
• 1 x Arduino Uno
• 1 x Arduino Mega
• 3 x Hall effect rotatory sensors
• Old Mini-ITX PC Case

Mechanical

• 1 x USB Hub
• 3 x CNC and welded motor levers
• Some meters of 35x35mm squared steel tube
• Some pieces of plywood
• 2 meters of 60x80mm extruded aluminium bar
• "Old" 2DOF structure

Software

• • FlyPT Mover
  • Simtools DiY license
  • SMC Utils
  • MSFS 2020

Other materials like cables, screws, peripherals, etc.


I started cutting the universal joint of the prvios 2 DOF rig.


Next I modified the base piece to incorporate the three new motors with some metal working and welding.



Also was time to make the upper structure that will support the chair and the controls. That “H” in the center is also recicled from the old rig.


The cranks are made of 25mm squared tube.


After some painting job the main pieces are almost done.

After two months the motors arrived few days ago and instantly I started to install it.



With a 3D printer I print the Hall effect sensor suports. I also made some MDF levers for testing while able to made the "real" ones.



Time to electronics. At the moment all the electronics are thrown like that coz always can come some problems and in this way is easier for me do the changes.



Ready to start testing!!

A problem I detect now is the motor noise. Is a rumbling-like noise and my though it is caused by electric noise.



In SMC utils I can see the yellow line is very very noisy and I think it is the cause of the problem. I will made a better electronics installation soon when some electric sorts arrive (magnetic clips and cable managment)



The controller boards also get very hot when I put some load, around 50 Kg up on the chair

Do you have a link to where I could buy these motors?

Yes, here:
https://www.alibaba.com/product-det...a2756.order-detail-ta-ta-b.0.0.9e672fc21euvmO

Continuing the build and after made the new levers I was able to join the cranks and upper structure. I install the chair too and some motion tests with load but still with temperature problems

Hi Noorbeast. Thanks for the reply. The problem is with the boards and some load, with the rig empty the boards only get warm but with load the boards raise the temperature up to smell bad, the motors at the moment works well.

Thanks

Hi bro, yes i got same as your problem using the 100a driver. i use 300w motors and now this is the second time my board burned.

But i use 1x 100a driver for 2 motors (2dof), and you're using 3x 100a driver and each one for motor.

i'm not sure but i think maybe you can connect 2x 100a driver together for 2 motor and the last one for one motor.

Hi, thanks for the reply.

I decided drive each motor with his own board to make sure each board is capable to run and drive the motor more than enough

Well, I rewired all the electronics with protected cable and way more tidy and the problem with the noise go away 90%. I'm still waiting for magnetic clips so I think it will be the icing on the cake.

Well, in the other hand the temperature problems stills as one of the board literally burned yesterday. I don't know but I think buying that kind of boards is a lottery. I'm searching sabertooth boards but is very very hard to find it and the ones I can see are very expensive, 200€ per board (I need 3).

I already wrote to these board seller to see what's happening with my "100A" boards that can't manage up to 30A.

Regards!

Finally I'll go ahead for two sabertooth 2x32 boards. They fits to my motors (750W/24V = 31,25A). As I can see they are well known boards and works perfect.

I'll update as soon as I can, very busy weeks are coming.

Edit: Finally I go for 2x60 Sabertooth boards

Hello again. After a few weeks trying to solve the problem with the Chinese "100 A" boards finally I returned it and got two Sabertooth 2x60 boards (what a huge boards, connectors, heatsink, construction quality...). The high temperature problem is gone but there is still running A LOT of amperage, maybe the motors lifetime will decrease significantly but at this time I don't discard the option to add the spring workaround to help the motors lift up the weight. But well, that is a future work.

Now I want solve other problem. I'm using two Arduinos running the SPS code, one Arduino UNO and one MEGA. at the moment I control motor 1 and motor 2 with UNO (they were connected before) and motor 3 with the MEGA. I configured the dip switches and I can configure and control each motor individually with SMC3 utils. There is some inner noise in the motors but I'll try to solve it later. I'm using FlyPT and I configured two serial outputs, one for UNO (with the actuator 1 and 2 to the output string) and one for MEGA (with the actuator 3 at the output string) (COM3 and COM4 respectively) and here is the problem. The UNO runs perfect and M1 and M2 runs as expected but M3 doesn't. It only moves if I put all the actuators in the output string of the serial output but in this case all the motors, especially M3 start running crazy and also makes M1 and M2 running weird. Is it possible FlyPT can't manage two serial outputs? Is there some additional config to output controls to two SPS controllers? I search for how to's on how connect multiple Arduino to FlyPT without success, all the people only configure only one output and I assume they don't have the same problem I have. What I don't try yet is configure it with Simtools coz my DIY license is not working, I'll contact with support soon.

Thanks!!

Yes but SPS can work with UNO and Mega. The problem is not with SMC3, SMC3 works perfect with both boards, I have the problem with FlyPT connecting two boards.

Thanks Noorbeast!

Yeah, finally I already get Simtools working, I didn't read well the instructions and I was trying to validate the license with the first code, now it is working.

I'm having the same result with Simtools, after read the user manual I don't know how to configure the serial interfaces to work with two arduinos.



I asume the interfaces config is as the screenshot shows but actually I don't know why to be honest

Thanks!

I think I get (I find actually) how to configure it. Changing the ''[C<Axis3a>]" to "[A<Axis3a>]" in the second interface.

Tomorrow I'll test it

Edit: Yep, problem solved, now both Arduinos and all the motors are working.

Interface 1 (to Arduino Mega) Output : [A<Axis1a>][B<Axis2a>]

Interface 2 (to Arduino UNO) Output: [A<Axis3a>]

Hi, today I have made progress with the build. The controllers works fine and lift a sine wave in the heave axis running in FlyPT for a while without get warm. At the first time when I sit on the chair the motors were stuttering but I almost solve it tuning in SMC3. When I start a flight it moves if I'm not on it but when I jump on it the small and gentle movements are not noticeable but the fast and "heavy" movements are done perfectly.

Kp is configured to 140 not more coz if I increase that the motors starts to snore and jitter even if I increase Fpid.

At the moment the motors are only running with the batteries (2 x 12V 95Ah in series), tomorrow I'll connect one by one three power supplies in parallel (with huge diodes) to see if the performance changes.

I'll update!!

Hello, this weekend I started doing movement tests. I think I tuned all the SMC parameters but the motors are still jitter and sometimes one of them start to bounce. The PWM output line looks noisy but the green line from the pot (hall effect) looks good so I asume that is not the pot getting EMI from the motors problem. As far as I increase Kp the problem grow up but without a "decent" Kp the smooth and little movements are "filtered" by my weight (I can hear the motors trying to move) and only the big/great and fast movements are noticeable. Also, when the motors stop inside the motors are doing a kind of scratch sound that maybe is not a problem but is disgusting to hear.

At the moment I'm only using two 12V 95Ah car batteries and the plan is connect some 24V 1200W (50A) PSU in parallel to help the batteries and even charge them.

Edit 1: Today looking closer I noticed a very very little pulses in the green line (the pots) and a magnified signal of that reflexed in consequence to the yellow line so I can't discard the noise problem at all.

Edit 2: I changed the Arduino's USB to a USB hub installed under the chair and the Mega starts to run smoother while the Uno doesn't so I assume the USB cable is the responsable of the noisy signals. Next step is change and test with other USB cable the Uno and see if the problem will be solved.

Here is a video of the today's motion test with Kp increased to 180 and PWMmax decreased to 135, I think I'll be close to finish when the noise problem will be removed, I hope you like it:

hello.
I've been watching you work hard to fix the problem.
I'm glad it seems like it's almost resolved.
Is money the solution after all?!
anyway,
I am also preparing such a 3DOF.
I only did basic operation tests with three 24V 400W 60:1 motors and three Chinese 100a boards.
I wonder what will happen once the frame is built and weight is placed on it.
Thank you for sharing.

P.S. If you use a ferrite core in the cable that carries the signal, noise will be reduced.

-Google Translator