Hercules is going through a major rework for Motorama this year. The overall principle of the robot is still the same. But some minor tweaks will hopefully be improvements. The two major changes are the change from store-bought hinges to a custom hinge cut from UHMW, and using Banebots wheels instead of Lite Flites. The custom hinge set up improves the grabber geometry so it can grab, lift, and reset more easily. The change to Banebots wheels comes from the fact that my magnets got destroyed last year and mostly helped me in sticking to my opponents instead of the ground. This version of Hercules has lower ground clearance and firmer wheels in an attempt to remedy this and provide the down force needed to lift its opponents. In addition to all this, I switched over the robots electronics to all 2S LiPo (7.4V) in order to decrease the top speed of the robot as it was a little uncontrollable last year, and allow me to use a high voltage servo without the need for an external BEC.
El Tigre performed very well and for what the robot is (a body I designed around a Fingertech kit that I won as a prize) I was very happy with it and didn't feel the need to change much. The two problems it had were browning out under high current loads, and the motor mounts breaking. The brown-outs were a combination of me using an under-rated battery to save weight and under-rated connectors because that's what came with the battery. I replaced the old battery with a larger, higher capacity, higher discharge battery that used XT-30 connectors instead of the JSTs that were previously used. Secondly, my custom 3D printed motor mounts performed well until the end of the competition where I was thrown around too much and the screws all stripped out. I have added heat set threaded inserts to fix this. Both of these changes added weight to my design which was already barely under the 3lb limit, so I will have to do some weight reduction, but other than that it's mostly ready.
Butcher also did great at Motorama last year. Most of the things I wanted to fix after last event were things that I was planning on doing before Motorama 2018 that I just ran out of time to do. The biggest issue Butcher had was reliability in its weapon and drive train. The weapon reliability came from the issues I had with the belt not being the right length and having to adapt accordingly. This version included a proper length belt as well as the actual tensioner system I designed for the previous iteration. The drivetrain issues I had were because my over powered brushless motors kept melting themselves under the load. I dropped the battery voltage from 6s to 5s to help this as well as ordered new lower kV motors that should help.
My name is Michael Connerton. I am currently a mechanical engineering masters student at Case Western Reserve University. This website is a blog of my exploits into the world of combat robotics.