3 dof platform what you think(Elastic-Actuated Delta Robot)

3 dof or more?

Cool looking and a novel idea , but way too complex for what it is - a standard stewart platform would be allot easier to build/drive and give a true 6DOF.

I do not understand, it's very similar to my tutorials which has already been built with quite a few copies:
https://www.xsimulator.net/communit...lator-building-tutorial-3dof-heave-axis.9249/

Three ball joints suply, split the connecting rods and lengthen them ...
The difficulties seems easy to overcome ...

True, builds like yours have been around for a long time - maybe this variant just looks complex - inverted delta 3D printer . Your build although does not have the high angles and required leverage as displayed in the video.

It also looks like it can't yaw? Maybe I'm missing something there.

Quote from the youtube comment: "This is a 3-DOF Delta parallel robot actuated by series elastic actuators, designed and built by an undergraduate team at Northwestern in 2017 as part of their ME 398 senior capstone design course. Here it demonstrates motion of the platform in the three actuated directions, x, y, and z."

If it can not make the yaw effect in the strict sense (pivoting on the axis), it can make lateral and longitudinal displacements.

And I do not see how this would not be possible by modifying the elements cited in my tutorial.
Of course the position of the crank is to review as well as the elements mentioned above but it is quite achievable and fairly simple (for me ...)

These types of mechanisms are used in high speed pick and place machines, and are the precursors to the mechanisms commonly used in delta printers.
The mechanics guarantee they can't roll pitch or yaw.
If you want to introduce a 4th axis, you'd need to introduce an extra actuator somewhere.

Certainly I did not push the reflection, but nothing prevents to make a simulator.
The only effect that can not be reproduced will be the lace effect (pivoting on the central axis).
Compared to a 3DOF we gain the lateral and longitudinal movements.
And without the need for additional power, perhaps a little extra power ...

If you scale this up to put a human on it then you have quite long levers off the motors (more torque required) driving a small platform (more torque required) - I therefore would expect quite a bit more power/torque would be required from the motors in comparison to your build to move the same load at a similar speed.

Given that the cranks (lever) will be longer this will accelerate the travel speeds,
Moreover the possible angle of rotation is less than 90 ° then perhaps it will be possible to reduce the speed of rotation, thus with more reduction, more torque.
There is a small study to be carried out, but a priori no reason it does not work