Subject: Some mechanism studies
Date: December 31, 2006 11:56:02 AM EST
Hi Graham and Bill,
To understand the geometric constraints on the morphing handcycle a bit better, I made a very simple mechanism that can be dragged around to see the behavior of the morph. I matched the dimensions to a set of Photoshop concept images that Rory had created, and it seems like a promising evolution of the handcycle design. It uses a 26" rear wheel and a 16" front wheel, similar to the existing prototype, and has trail characteristics reasonably similar to the Hall cycle in the lowered position (4-5" of trail.)
I understand that the existing prototype has similar trail characteristiscs, so it would be great to compare a side view and see what we can learn from the existing model. Graham, could you take a screencap of the existing Solidworks model in low view and Photoshop it over the bikematch.png image? I just put the image on a new layer and set the opacity to 40% or so.
I found Rory a Solidworks 2003 mechanism tutorial, so it should be possible to replicate this mechanism in Solidworks, enabling easy project data flow. The design seems to have room in the upright position to place the feet behind the wheel, so it should be possible to steer in tight quarters. Rory is doing a Photoshop rendering of a proposed transforming footrest system; I'll add it to the existing mechanism to see if the math is viable.
So far, so good. The Torchmate people have confirmed that they can cut the DXF files, and we're awaiting a picture of the test cut tube end to go forward with that part, so things look very promising.
Eliot
Eliot did just a few hours of work here, but it was a crucial contribution. He proved that Rory’s side view model in Photoshop could work in a real mechanism. He modeled it in Pro-E, and this model was translated into Solidworks. This then became the mechanism basis for the Morph 2 design.
Here Eliot overlays in yellow the mechanism design. Note that it lines up perfectly with Rory’s side view, in both high rider and low rider modes