Nightmare underwent another transformation for the 2016 season. Here's a rundown on what's different:
New Titanium Arms
When I had the new titanium disc made last year, I was only able to find one huge plate of 1/2" thick titanium, big enough to make the disc from. However, there was a lot of this plate left over, so I decided to use the remaining bits to construct the new arms. The old aluminum arms had been beat up for so long, bent and straightened too many times, so it was definitely time to swap them out. The resulting arms are amazing! At 1/2" thick grade 38 Ti, these are definitely overkill, but I didn't want to have any problems with these bending or breaking, so I went for it! The arms are designed specifically to completely house the drive motor/gearbox, protected on all sides and completely enclosed.
New Wheel Guards
Last year's huge wedge-shaped wheel guards were a bit klunky. Sure, they would protect the wheels well from both horizontal and vertical spinners, but as I discovered in the rumble against Witch Doctor and Overhaul, the wheel guards ended up pushing my opponent AWAY from Nightmare's disc. Obviously not an ideal situation. So I decided to ditch the wedge shape in favor of a strong 1/2" thick Titanium "hubcap" wheel guard. Enough to fend off a direct impact from a spinner, but wouldn't get in the way of my attacks.
After 17 years, Nightmare's one last big flaw (risk of being flipped over) is finally resolved! With this new design of the arms, and with the weight savings of removing the huge Titanium wheel guards, I decided to make Nightmare be able to drive upside down. Instead of the obvious choices for a self-righting mechanism (a bar or hoop, designed to flip a robot back onto its wheels), or building drive motors on the opposite side of the robot, I went with a very unique idea that I don't know if I've ever heard of another combat robot doing. I wanted to be able to MOVE the entire drive system to the other side of the robot. Nightmare's arms can now ROTATE. We chose to call this his "Inversion Conversion." This system proved to be a HUGE challenge in the design. There were so many questions to answer. How best to power the rotating arms? How to lock it into position in either direction? How to control it? The engineering on this took most of the time I had in the months leading up to the 2016 BattleBots event, I had to design a pin locking mechanism that would pull the pins on both arms simultaneously, and then immediately as the arms begin to rotate, push the pins back outward until the locking holes were in the 90° rotation.
Since Nightmare can now drive inverted, and the disc is reversible via speed control, I needed to have new teeth made that would grab in both directions. The new teeth, built from the same material as before (S7 Tool Steel), are now symmetrical, and can grab and rip regardless of which direction the disc is spinning.
The complex system invovled in the pin locking mechanism required special custom software, integrated via an Arduino system, to assist in the control and timing of the pin release and arm rotation. I also added in some nice LED lighting that was not only decorative, but informative. When in normal operation, the lights show green. When the pins are in the withdrawn position, or the arms are being rotated, the lights go red. This is so I can see the status of the robot from outside the arena. I also did something that I should have done years ago. Instead of bolting all the electronics to the chassis of the robot, which makes repairs awkward at that angle, I built all the electronics onto a dual-layer polycarbonate board that is shock mounted to the frame and can be removed from the robot (and worked on inside in the air-conditioning!). Simply unplug everything and pull all the electronics out of the robot on one board! This makes for easy repairs.