Rotary 6DOF motor attachment point

I have a question if the arrangement of the motors in the rotary 6DOF has any meaning as to the platform performance ? ( pitch, roll, heave, sway ) or other parameters ?
Below two 6DOF rigs to illustrate what I am asking.
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The short answer: yes

The longer answer could fill books....
Just the most important considerations:

• If you don't have weight support (gas springs) the static weight of the rig is the most important reason for motor heating. So if you don't have plenty of motor power (no AASD servos or similar) the most important thing is to keep the static forces low.
• The higher the angle in the triangle in the picture the higher the static forces are. It has proven that an equilateral triangle (when viewed straight from the rear) is a good compromise.

• The smaller the red triangle the more roll and pitch you get for the same actuator movement while the static forces remain the same. So make it as small as possible without generating collisions with the seat in the extreme positions.

Having crank arms with multiple bore holes is a good idea. This way you can always trade force for speed and stroke if necessary.

The higher the angle in the triangle in the picture ?

More than 90° for the upper angle in the lowest actuator position is definitely bad. Close to 60° in the lowest position is good. An extremely acute triangle would also be bad because the forces for sway, surge and yaw become extremely high (pushrods almost parallel).

I'm ashamed to admit it, but I completely misunderstood your answer

And I'm not really sure if I gave the answer you were looking for. Maybe you describe what you are planning to do.

And yes, the red triangle would be better than the yellow if you want to optimize motor load and heating. But the yellow one gives more heave for the same angular arm movement but less force per motor current. There are always pros and cons. If you tell me what the problem is or what you are aiming for then I could hopefully give advice.

I am thinking how to make 6DOF on 24V 250W motors, there are two threads on the forum
SilentChill
https://www.xsimulator.net/communit...bertooth-2x60s-was-mms-and-arduinos-osw.6948/


Ronan Design

https://www.xsimulator.net/communit...g-msfs-smc3-flypt-transducers-controls.19053/


The arrangement of the motors in each of them is completely different and I wonder what effect this has on the swing ranges achieved by the 6DOF, tilt which arrangement of motors gives stronger tilt and which gives heave motion, is it completely indifferent and it is just a matter of choice of the designer?

Translated with DeepL.com (free version)

Can you please provide links to pictures of the rigs you are referring to? If I go to the latest pages of the threads of @SilentChill and @Ronan Design I see that one of them has linear actuators and the other rotary ones. But that's not what you are asking, I think. You mean SilenChill's design has the motors in a symetrical star arrangement while Ronan's motors are in the corners of a triangle, right?

Sorry, my mistake SilentChill made 3 versions of his 6DOF and they are all in one thread , the first version was on rotary engines
from page 12 to about 25 are shown photos or videos of the working 6DOF rotary
https://www.xsimulator.net/communit...h-2x60s-was-mms-and-arduinos-osw.6948/page-12

Yes , exactly I mean the differences between SilenChill's design has the motors in a symmetrical star arrangement while Ronan's motors are in the corners of a triangle,

Sorry, I still havent found good pictures of SilenChill's platform. Problems with my browser not displaying embedded pictures again... Never mind
There are some good theroretical articles about 6DOF stewart platforms in the FAQs. For example math basics and a caclulation spreadsheet.

Doh!
The picture in your first post with the wooden frame is from SilentChill's platform, at least one of them, isn't it.

I also have a problem with displaying photos but I discovered that Microsoft Edge displays all photos .