Hello Sketchup folks,
I use Sketchup to create my drawings when I am working on a new design and I am starting from a blank screen. I have found I can pull the Sketchup drawings into Keyshot and get renderings. I think Keyshot allows more flexibility on the lighting and materials visual properties, so I put some of my renderings on my website as png images free for download. I remain a little surprised that the robot crowd does not seem to be able to create a true human mimicking robot hand. I think the issue is that they insist on use of electric motors/gearhead systems and the electric motors required for the force and speed of force values that are correct to mimic a human, a motor that can do this in the form factor required would need an input electric power that would melt the wires of the motor. I think it is all very easily done with hydraulic cylinders but, whew!, the robot crowd really does not like hydraulics. Mysterious. Anyway, I created a human mimicking hand design in Sketchup. Human muscle obtains max force and speed of contraction in 150msec, human design uses leverage from the muscles to the bones. In the human hand the intrinsic muscles of the hand leverage to the phalanges is about 2:1, and finger abduction/adduction also flexion/extension forces from the intrinsic muscles of the hand is about 9lbs, so the muscles need to develop 18lbs force, contraction speed is 15cm/sec. Muscle size is about 8mm diam x 20mm long. There is no electric motor/gearhead system that can do this.
I designed the hand to also have all of the ranges of motions of all of the parts of the hand as does the human. Again, the robot crowd using electric motor/gearhead linear actuators, these are so large, that form factor issues force the robot crowd robot hands to not have all the possible dexterity abilities of the human hand.
I wanted to get the hand designed printed via 3D printing using PETG, but minimum wall thickness with PETG is 0.8mm, so I had to re-design the parts to get them up to this minimum thickness. I have been working along with this. The Asian CNC folks, many of them contact me via Linkedin to create these parts, but they all state they need step files. I have (finally, whew that was complex) figured out how to send Sketchup stl files to Autodesk Fusion, and then a set of steps that will allow Autodesk Fusion to convert the Sketchup files to proper step files that the Asian CNC folks tell me are completely ok step files for them to create 3D printing of the parts in PETG polymer. I think I just finished the wrist ranges of motion setup. I plan a set of YouTubes about this. Here is my most recent YouTube, at that point all I had almost finished was the fingers. Here’s the link: https://youtu.be/BErP7N0OyYo
I thought you might enjoy. I will see if I can include my most recent Sketchup drawing where I am finalizing the new larger cardan joints/hydraulic cylinders and their placements to allow the robot hand to have proper ranges of motion for abduction/adduction and flexion/extension at the level of the wrist.
Here is that Sketchup file, there are hidden objects in it because, if I keep them visible, it becomes too hard to really see what I need to do.
Enjoy! Dr. Gray
Abduction-Adduction Flexion-Extension Wrist 8mm CYLINDER v592.skp (9.7 MB)