Showroom FlyPT - 6DOF Brushless DIY Actuators

Yes, not moving - good pickup @Flymen . Look forward to see it moving under a load. I have a lightweight base also and it use to slide around the room so much during use that I ended up locking it down on rubber mats. There is allot of inertia involved once you have a passenger on board and the rig is changing direction quickly.

Tomorrow I will mount the seat and make a video with me seating.
Just need some longer screws.

So here it is, with me seating (that's more than 80 kg unfortunately).
You can see at around 0:38 the structure lifting from the ground , just with a pitch.
I have some rubber under the structure, but that's not enough.
This was using simtools test sliders.
I need to improve my axis assignment. Anyone want's to share values?
And has Thanos said, use some low pass and high pass filters.

my simulator jumps and moves with two batteries each 20 kg ( my base weight about 60kg ) so if you do not intend to add mass to the base then you will have to fix it to the ground

while heave move actuators do not go evenly up, some are slower than others, why?

Yes I noticed also.
I made two boards, and one of them is slower than the other.
Could be the level shifter with some problem. I have to take some measurements. It's pretty noticeable on calibration, with a slower speed.

I would like to share my values but i'm not still there I can not wait to get to this point!!!

for example, these are mine for dirt rally, but yours will be different because you have a different distance between mount points of actuators...

Thank's.
They may be different but it's an help.
Why Extra1 instead of Yaw?

Yaw is good if you have a 360 degree yaw capable sim, as it is just a direction of heading. For everyone else use traction loss, which in this case is available in Extra 1.

It also depends on how you have numbered and placed your axises in relation to the 'front' of the sim.

Now that I have to wait for the encoder card, I will start the base platform .
I wanted to compare your dimensions with them (photos) I have 570mm of travel but with the limits switch and lineaire bearings the reality is 470mm total.
The total distance to flexible joints top to bottom is 950mm ( when the actuator is at minimum position).
When I see your video , the base move a lot with you on your seat !and may be I will do like this for the bottom joint ! ( see pic below) !!​

I'll be following you soon too.

Those are my dimensions:





Took a while to make them.
I wanted to make a "perfect" hexapod.
Top is equal to bottom with a travel of 445mm (less with limit switches).
On the right are the actuator travels: minimum, medium and maximum.
On the left the height of the top structure: minimum of 623,4mm up to 1145.4mm.
The corners are the centres of the u-joints.
The actuators are mounted to be on those planes

Made some tests to find where was the speed problem.
I thought it was in one of my boards, but after looking better, there are two actuators slower than the rest.
So the problem is on the controllers.
I have 2 from ACT motor and 4 from Wantai. So here's the reason.
Although the specs seems to be equal, they are not.
Ordered two more from Wantai and I think I will introduce a speed calibration when I calibrate for limits.
I hope a simple linear adjustment is enough.

Making some tests with Inverse kinematics.
I decided to make a spreadsheet to test formulas before testing on the platform:



Made a Google sheets version to share: https://docs.google.com/spreadsheets/d/1OCStvbkjkhra0w-cb4L4tYnXVJ4fm3GsQPSJRh0RUUY/edit?usp=sharing

Great to see the thing moving. Too bad you have two slower controllers.
I really like the sheet you made. I will be studying it before i start building.

Did you ever try that Chinese bldc controller? Looks like a compact solution to me.

Not yet, but I want to.
But it lacks an aluminium dissipation for heat.

I have updated the spreadsheet.
Link is the same: https://docs.google.com/spreadsheets/d/1OCStvbkjkhra0w-cb4L4tYnXVJ4fm3GsQPSJRh0RUUY/edit?usp=sharing
Now it allows to define a centre of rotation.



Old one was updated to:

Holy cow! This is an impressive build! Great work mate. Keep it up. You're definitely one smart cookie!

I got a question for you. When designing your frame is there a rule of thumb to use for your actuators, like at their center value they should be 90 Deg where the 2 join the seat frame or something? If that makes sense?

Thank's

Well, my thoughts where:
-Smallest size possible, and I think that's almost impossible to make it smaller in this configuration.
-Made design thinking that with platform at lowest position, actuators still have more than 45º relative to the floor (they have almost 50º, they are made to have axial loads).
-Distribute evenly all the forces, centring the load the best way possible (seat more at back to compensate weight of wheel and pedals).
-Actuators at vertical position while having maximum rotation was also something I desired, avoiding all load in one direction (of rotation)
-Leave space (125mm in my case) so actuators don't colide between them
-Lower the seat, the maximum possible for access reasons and also lower the CG

But:
-At some poses, the actuators can have angles lower than 45º
-Having the seat lower will reduce some angles compared to the centre of the top platform, since I will also change the centre of rotation

Check first page of this thread for more dimensions.