DIY 2DOF Budget Build

Awesome!!! I love happy endings.

I made the 160 km. round trip to the big smoke to get a replacement G920 wheel from where I purchased it from and luckily they had another in stock and were willing to do swap rather making me wait god knows how long to get warranty claim from Logitech.

Back to the rig and we have movement, but only limited at the moment so I need to do some reading on how to set up profiles.
Hopefully I am on the home stretch

Congrats on getting the rig moving.

For setting up motion profiles, you can never go wrong with this advice:
https://www.xsimulator.net/community/faq/steps-to-create-a-motion-profile.228/

I used that info tonight, and am having great success so far!!!

Good luck!

Cheers!

MarkusB made a post which really helped me keep straight a few basics .
Its going to take a few hours of experimentation playing with the tuning and axis settings before it started to "click" with me.
I found that even some good settings may not feel that good to you at first.
Keep in mind this is still a simulation of motion hence the word motion simulator.
For me it was not till I got my VR headset going that I went from "meh" to "wow"....
The Markus speaks ::::::::


a pure 2DOF simulator can only perform pitch and roll movements, while the surge, sway, and heave forces need to be mapped onto these two:

• surge is emulated with the pitch axis: acceleration = positive pitch angle / braking = negative pitch angle
• sway is emulated with the roll axis, but usually in the opposite direction. Example: When you are driving in an inclined left curve, the car tilts to the left, but the sway force presses your body to the right.
• heave is emulated with the pitch axis, but probably with rather small amplitude compared with pitch and surge.

The problem with this kind of emulation is that the surge/sway g-forces tend to eliminate the pitch/roll angles and vice versa.

Example:
You are driving downhill, causing your car to accelerate. Acceleration increases the pitch angle, while at the same time going downhill reduces the pitch angle. Depending on whether pitch or surge causes the larger motor movement (depending on your axis setting), your seat moves forward or backward. This can lead to quite confusing sensations.

This may also be the explanation for what you described in this sentence: "It seems like I have a lot more pitch going up hills than down."

An approach for solving this problem for a 2DOF simulator is to add a g-seat. You will find multiple builds in this forum (including my own, for which I will hopefully post an update this weekend).
Basically a g-seat consists of 1 or 2 sets of paddles that apply pressure to parts of your body.
For example, surge and sway are simulated with backrest paddles that push against your back. For surge, both paddles apply pressure, and for sway just one.

The forum member @SeatTime has gone a step further and developed a "g-system" that pulls your upper body forth, back, and sideways with bowden cables.

Hope this helps.

Best regards,
Markus

Broken
I was trying to get the motion profile in Sim Tools setup but it would only pitch forward and stop and would not come back when doing manual tuning and I would have pick it up and move it back to the center position and that is when I noticed the whole motor mount was moving which I thought was just some flex, but oh no it has cracked above the weld and is almost cracked right through.
So I will have to tig up the crack, and I am adding a 16mm. thick bar as a brace between the two motors and hopefully that will stop the flexing.
No happy Jan, but at least my weld did not fail if that is a bonus or not.

Pic shows the brace that I will be welding onto the motor mounts.

I should have used 6mm. steel plate for the mounts instead of 4mm. but the thing weighs a ton as it is.
It's handy being a bachelor because if I was still married she might object to me welding inside the house as I don't want to completely
dismantle the whole thing when I can hit it with the tig welder that makes no spatter and does a neat job with better weld penetration.

OK.
Well I welded up the motor mount and added the motor brace so it is know nice and solid and it is almost behaving as it should all bar for one small problem.
My roll is Pitching and my Pitch is rolling !
I set them in the same sequence as Sim Tools Tuning Center is laid out.
I tried switching the axis arrangement around and it made no difference, so where am I going wrong ?
Here are my screen grabs

Quick Repair Job
Now for some touch up paint.

OK, so I fixed the problems with my settings and it's now doing what it should be doing, except it want to kill me by throwing me out of the seat especially on pitch and roll.
From memory I had Roll @ 30% and Pitch @ 20% and it's movements were violent.
So I Upped the % values on both Pitch and Roll to 100% each and that tamed it down a little but it is still too violent to drive comfortably.
I also have moved the motors lever points back by 2 holes and that has moved the lever length from 100mm. to 50mm. from the pivot point and I still have two more holes that I can go back on if needed.
It also has equal mount points on the rig that gives me lots of leverage points and % points of movement
I have not changed any of the DOF filters yet, but I have turned on Ant-Rollover on all DOF's
Can I go over 100% in DOF force settings as I understand the larger the number the softer the output is opposed to low % values.
Here are my screenshots with the current settings.

I had another thought about the excessive movements and wonder if the settings in SMC3 would have any bearing on it's behavior
as I did change them from my previous settings and I lowered the Kp down to 100, PWMax 200 and Max Limit to 230 and those settings made the
movement in SMC a lot smoother a faster.
I based those settings roughly on from another thread on a Sabertooth driven rig

What I use.
Generic 2d basic.
40% on roll and pitch
35% sway
20% surge
0% yaw
0%heave
In the tuning panel 5 for pitch and roll.
surge 1
sway 3
Remember that the lower the tune number the more powerful the effect.
Once you get below a value of one the effect is amplified rapidly.
I lowered my Kp to 70 to reduce jerkyness.
Keep in mind you only have a 2 dof machine Roll and Pitch.
Its very limited . There are many options that either do nothing for your rig or just make it worse.
This is the opinion of a raw Nubee so be sure and take that into consideration.
I would advise a novice to just play with pitch and roll.
Then add bits of surge.
Then add some sway.

In the Game Manager I found that the Profile Editor to be very useful and simple and effective.
Adjust the Main Level %
At 65% I get a gentle ride
At 85% I get a pretty rough ride.
At 90% and above it is violent!

One last note.
If your driving skills are poor its more likely the ride will suffer.
We are at the age where race car driving becomes more of an approximation than a skill.

I did some searches an followed this thread https://www.xsimulator.net/community/faq/washout-gain-and-return.303/
and I added some smoothing, gain and retain and that calmed it down greatly, but AGAIN it is 4.30 a.m. down under I should be in bed
but I will sleep better knowing that I am making some progress.
So tomorrow I will do some more refining and make a few mods to the rig to brace my motor mounts some more and need some gussets from the motor mount plate to the base rails.
My upper attachment points are too weak and have bent under the load, so some more heavy duty plates are in order.
I'm off to Noddy Land,
Goodnight All.

Hi @Deane,
in addition to @noorbeast 's very true comments I saw that there is definitely still a basic mistake in your settings, revealed in this screenshot:

• "Roll" is a movement in which both motors turn in different directions.
• "Pitch" is a movement in which both motors turn in the same direction.

For this reason it cannot be correct that only one check box is checked "orange" for both DOFs.
Instead, either roll or pitch needs to have only one check box set to "orange", while the other DOF has both check boxes set to the same value (i. e. orange or black).
The easiest way to find out the correct direction settings is to only have one DOF (i. e. either Roll or Pitch) enabled and the other one set to 0%.

The "fun " just keeps coming for me.
I am slowly learning how to configure motion profiles etc and using my sim but in doing so I have managed to damage one gearbox by inadvertently driving it over center and jamming it which has hammered the soft bronze spur gear and now it sounds like this https://drive.google.com/open?id=1imFMmJ_iLPbkipIEcF4DdOofd5UEQj7t
I have got on to the supplier , Motion Dynamics and they tell me this g/box is not suited to my application and have suggested that it's lifespan would not be very long if I continue to push the g/box
in a sim, and have suggested I upgrade to heavier duty gearbox that will require some adaption fabrication to fit my motors that I still have and are working fine.
If I had the spare money I would upgrade the whole package to a pair of motors from this range https://www.motiondynamics.com.au/heavy-industrial/ or if I wanted to rebuild the whole thing I could try some of their Linear Actuators https://www.motiondynamics.com.au/heavy-industrial-ip65/ if they would work ok ?

I am only quoting what MD told me and my other side gearbox is quiet as mouse and they never seem to be under stress, if anything it has way too much power and torque with the 50:1 ratio.
I just intend to drive it until it stops, then I will worry about changing over to a more robust gearbox as they recommend, but I am open to alternatives.

Hi again, it's been a while.

Nice to see you've got the rig up and running after the electronics/programming issues.


Aren't your levers & rod-ends designed so that if you were to drive them past center that they would just rotate 360 degrees?

I might be mistaken, but I thought that was why you had put the spacers on the axles during testing in order to get them out past the frame.


As far as the problem gearbox goes, are you able to disassemble it and move the gears to an unused & undamaged portion?

Since we are using roughly only 1/3 of the gear's wheels, technically we should be able to extend their life by up to 3x's just by rotating them to an unused portion when they show signs of wear.


Hope you get it sorted out soon enough, Cheers!