Guizmo, Nicholas Seward:
I like the combination of the zero back lash of the Double Lamina Compliant Joint (DLCJ) bearing/joint, and the non linear toothless elliptical gear or cam correction as it affords weight, and part count reduction, moreover it works with the Simpson firm ware without further modifications!
I believe I have a solution (or a starting point for discussion) that incorporates both the DLCJ bearing/joint, and the elliptical gear/cam, please see attached blueprints.
Comments/Notes/Questions:
I'm using wide control arms/linkages to help increase rigidity (side-to-side sway), and I have eliminated the tie rods that connect adjacent DLCJ bearings. In addition, I added DLCJ bearings to the upper shoulder pivot (stepper motor axis), and to the wrist joint (end effector).
For reference, the DLCJ bearings are 1 inch wide (not shown), the DLCJ bearings center to center distance is 2.5 inches, and with an over all width of 3.75 inches. That's worst case, I have not taken advantage of all the surface area for tethering/binding.
The elbow pivot was given enough clearance for a 4 inch diameter pulley, for a 4:1 ratio from the stepper motor pulley. For reference, I have drawn in a 2 inch diameter timing pulley in the forearm joint.
The arms are 6 inches long measured from the distal pivot of the arm, to the furthest DLCJ pivot, and the elliptical toothless gears are for reference only. The longest part is 6 inches.
To adjust the timing belt tension the upper arm needs to be constructed of two parts (not shown). I'm considering guides of some flavor, plus dual turnbuckles or jack-screws.
Can you utilize the DLCJ bearing on the pivotal base/pedestal (vertical axis of rotation)?
Can the Simpson firmware be used in it's current configuration without modifications for the power train that I have drawn?
Is the elliptical gear or cam profile scalable, or does the profile need to be recalculated for a given arm length?
What plastic material will be used most often with this design? I would like to get a rough idea of what the wall thickness should be. I'm also thinking of shelling the part, and adding ribs in critical areas, instead of using 20% infilling. Will the shrink rate and warping be acceptable with no infilling, or does the infilling help prevent warping?
I appreciate your feedback, and I'm looking forward to a geometric solution.
A2
I like the combination of the zero back lash of the Double Lamina Compliant Joint (DLCJ) bearing/joint, and the non linear toothless elliptical gear or cam correction as it affords weight, and part count reduction, moreover it works with the Simpson firm ware without further modifications!
I believe I have a solution (or a starting point for discussion) that incorporates both the DLCJ bearing/joint, and the elliptical gear/cam, please see attached blueprints.
Comments/Notes/Questions:
I'm using wide control arms/linkages to help increase rigidity (side-to-side sway), and I have eliminated the tie rods that connect adjacent DLCJ bearings. In addition, I added DLCJ bearings to the upper shoulder pivot (stepper motor axis), and to the wrist joint (end effector).
For reference, the DLCJ bearings are 1 inch wide (not shown), the DLCJ bearings center to center distance is 2.5 inches, and with an over all width of 3.75 inches. That's worst case, I have not taken advantage of all the surface area for tethering/binding.
The elbow pivot was given enough clearance for a 4 inch diameter pulley, for a 4:1 ratio from the stepper motor pulley. For reference, I have drawn in a 2 inch diameter timing pulley in the forearm joint.
The arms are 6 inches long measured from the distal pivot of the arm, to the furthest DLCJ pivot, and the elliptical toothless gears are for reference only. The longest part is 6 inches.
To adjust the timing belt tension the upper arm needs to be constructed of two parts (not shown). I'm considering guides of some flavor, plus dual turnbuckles or jack-screws.
Can you utilize the DLCJ bearing on the pivotal base/pedestal (vertical axis of rotation)?
Can the Simpson firmware be used in it's current configuration without modifications for the power train that I have drawn?
Is the elliptical gear or cam profile scalable, or does the profile need to be recalculated for a given arm length?
What plastic material will be used most often with this design? I would like to get a rough idea of what the wall thickness should be. I'm also thinking of shelling the part, and adding ribs in critical areas, instead of using 20% infilling. Will the shrink rate and warping be acceptable with no infilling, or does the infilling help prevent warping?
I appreciate your feedback, and I'm looking forward to a geometric solution.
A2