Design is an iterative process, that rarely produces optimal or even usable results on the first try. This series of posts will show some of that design process including the flaws of the initial prototypes and how they were resolved.
So this arm design looked like a good idea for a robot, if it had some more mobility.
So, how do you design a cable drive continuum robot appendage? Build a prototype.
How do you build a prototype? Build a cable drive prototyping system.
transfer orbit. A curved hole of the required shape can be made with a 3D printer, but it is difficult to manufacture with injection molding. Design for manufacturing.
Hope you're wearing your safety glasses, because that cable is about to unspool violently. Here you can also see another problem where the hole was placed in the center along the axis of the drum, which leaves little room for the cable to spool. The next design moves the hole closer to one side.
metal brad and a Protobrad™.
Here is a video of the system in action. Future versions will support two cables on the drum, with one being wound as the other is being unwound. This configuration will remove the need for the spring.
On to the next iteration.
Update: U.S. Navy Wire Rope Handbook (6.2MB PDF)