• Two thin pieces of material on either side of the segment (with nothing, just empty air/necessary supports, in between), just enough to connect to the actuator/previous segment and support the rest of the arm
• Actuators and the next segment are located between the two frame pieces, making it symmetrical
• Nowhere to hide wires or power transmission parts at all
• Would be with a strong, lightweight material, but (I assume) would make for a very flimsy arm otherwise
• Seems to be used more on lower segments, my assumption is that it would be harder to implement well higher up when you have more parts closer together
• Actuator and everything contained in the joint module

• I feel like this is just different enough from above to separate it
• Similar to above with the symmetrical frame, empty center, etc
• Wider frame is used to support motors, gears, etc instead of strictly being a link from one segment to the other
• Seems more commonly used throughout the entire arm (as opposed to just the lower segments) than above
• Provides more mounting points/opportunities to hide/manage wires than the thinner option
• Also provides real estate for sponsor panels

• Literally just a cylinder from one joint to the next
• Seems more difficult to mount motors and stuff than the two-piece frame (?)
• Wires can be routed through the center if it's hollow

• Who needs flimsy sheet metal?
• Solid, strong, heavy
• We are not lifting heavy enough stuff to warrant a monster like this, and even if we were, I don't think we want to use the majority of our weight allowance on the arm

Fancy casing

(More of an optional addition than separate style)

• A flimsier frame hidden underneath lightweight molded plastic to hide wiring and give it a sleek look
• Also has the advantage of protecting the inner parts
• Adds extra and mostly unnecessary weight, though

• Very light: most actuators moved to the bottom.
• favorable center of gravity: all actuators near the bottom.
• Sleek design, without the requirement for elegant curves
• May be limiting to design with 6dof
• poor design of the linkage bars may lead to an unacceptable tolerance stackup. This can be easily avoided with proper design and tolerancing.
• Reduced wire length, everything near the bottom
• More space at the wrist