Motorama 2019 was a bit of a disappointment for me. As I'll go into in detail below, I lost a lot of matches for simple things that I easily could have fixed, or on close judges decisions. Overall Team ConnBots ended up 5-6 on the weekend. This was the first time in a long time I had lost more matches in a weekend than I had won. Luckily though, the robots came out mostly unscathed so I can simply fix some of the small failures I had and be ready for the next event I go to. As with my previous updates, I will update this post with videos of the fights as they come out.
The updated version of Hercules worked better than the previous versions, but it still had issues. The new grabber worked great, but even with the magnet on holding the back end down, I was unable to drive my opponents around. This could have either been a result of my under-powered drive motors stalling out when the combined weight of the two robots and the magnetic downforce were loading them or the wheels sliding on the incredibly dirty floor in the arena. I will have to do further testing to determine the root cause.
Pan Handler was a full body lifter built out of a dollar store dustpan. This was a really creative design. I love creative and different robots. Fortunately for me though, the plastic dustpan did not ride closely to the ground and I was able to get underneath him and push him around a lot, although I was never able to lift him due to the large, unique shape. This didn't matter as he couldn't lift me either. Hercules won on a judges decision.
Speed Wedge 1 was a 4WD wedge. It was having some driving issues and was significantly slower and less powerful than it should have been. This allowed me to get around and lift it multiple times. Although, as stated before, I was unable to drive around with the robot lifted in the air as I wanted. This still made for a good showing for the judges and was enough to get the decision to move on to the next round.
Ratfish is a very powerful servo flipper robot. I was pretty excited about this match as we have similar designs and it would be a good driving match against a veteran builder. Unfortunately when I turned Hercules on, the servo was not working and due to the tournament layout, I could not postpone our fight. This meant Hercules was basically just a floppy wedge bot. Since I couldn't articulate the wedge, there were several times where we ended up going head to head and he flipped me by going over the lifter plate, but under my side stabilizing forks, causing me to be tossed. I also could not adjust the claw when upside down, leading to me hobbling around the arena, upsidedown for most of the fight, waiting to be flipped back. Hercules lost easily on a judges decision.
Fire Arrow is another 4WD wedge bot that is well driven. I knew I would have to drive well in order to win this fight. There was a lot of back and forth grappling and pushing. I couldn't really get that good of a hold on him because he was mostly spinning wheels. In the end, the judges came to a split decision for Fire Arrow that I questioned, but the judges decision is final. And thus begin my hatred of Wedges for 2019.
In the end, I was relatively happy with how Hercules performed. I would have liked to have it working better but that mostly came down to time and practice before the event. Neither of which I had a lot of. While it had a relatively disappointing record on the weekend, It didn't face a single spinner weapon and is basically brand new still. I am hoping to find a local event in the near future to bring it to that I can continue to work out some of the issues I had.
Go Up was a 4WD vertical spinner from WPI robotics club. This was a well designed bot, but had a very tough match up in El Tigre. El Tigre ended up destroying the mild steel feeder forks and barely taking a single hit the entire fight. Tossing around Go Up for most of the fight, winning on an easy judges decision
Scrambler was a Kinetic Kit robot, very similar in style to El Tigre. While this is a proven design, I simply out drove them for most of the match. I got to their sides, knocking them around and eventually forcing them to tap out when their wheel hubs fell off and they were unable to move.
Weta is the original Kitbots vertical drum spinner. I was really looking forward to this matchup as it is a well experienced driver and bot. Unfortunately for them, Weta stopped moving second into our fight, without even making it fully across the arena. El Tigre won by knockout without even touching the other bot.
Nautiloid was a vertical disc spinner from Georgia Tech. I knew this would be a tough matchup for me as I coudn't really go weapon to weapon with him and would have to out maneuver him. Unfortunately, the weapon on El Tigre stopped working after the first hit. I later found out the set screw that held the weapon motor pulley on was completely missing, probably before the match even started. This lead to me trying to push him around for most of the fight. While El Tigre did well at this, the rather destroyed floor made it difficult and lead to him getting a few good hits in that swayed the judges giving El Tigre its first loss.
Mondo Bizzaro is a Kitbot drum spinner. While it looked the same as Weta, I knew this fight wouldn't be as easy. El Tigre was winning most of the match. It won a couple of weapon to weapon hits and jammed Mondo's weapon for most of the fight. When it became unstuck, he got a lucky hit that snapped my weapon belt. Turning the tide of the fight. I though I still had a good chance to win up until the last few seconds when I got stuck on my side after a big hit. El Tigre was counted out for its second loss of the tournament.
El Tigre was the one bright spot in a rather dissapointing weekend. The only robot I had that had a winning record and with its only two losses coming to the eventual 2nd and 3rd place bots. Both of which could have been easily avoided with some minor revisions. That being said, I think it is time to retire El Tigre. I am at the point at which three bots is too many for me to handle alone at an event and I would need to reinvest some serious money and time to remake El Tigre to where I'd want it to be. I will likely be selling it in order to help pay for future bots and allow the usable parts to not go to waste.
Butcher was by far the most dissapointing robot of the weekend. While most of the changes I made were relatively minimal, they were untested leading to two quick and aggravating losses for a robot that placed 4th at the same tournament last year. Most of this came down to luck of the draw of the tournament and a tough judges decision, but again, as with Hercules, it came out unscathed and will be able to fight again soon with few revisions.
Eulogy was a last second wedge that weighed in at only 7lbs. I severely underestimated it though as its relatively light weight gave it tons of driving power. I got one good hit in before he slammed me into the wall and I threw myself into the air causing my battery to come unplugged and knkocking me out for the loss. The extra room I added to the interior of Butcher for this year allowed enough room for the battery to shift and unplug itself on a big hit. While dissapointing, this was a simple fix. I was still confident as this is exactly how I worked my way back to a 4th place spot last year after losing my first match.
Splayed was a solid 4WD wedge. I was pretty upset with how the tournament bracket fell out as this was the worst possible matchup for me at this point. I knew I would have to take out their wheels without breaking my own weapon belt in the process. Thankfully, this time the batter stayed connected through a few huge hits. But eventually the weapon belt came off and I was forced to try and push my way out. Eventually one of the brushless drive motors gave out and we were both wriggling around the arena without doing much to eachother. I lost on a judges decision that, while fair, stung because I had done all of the damage to myself and thought I had fixed these issues already.
While this weekend was very frustrating for Butcher, I plan to do some minor tune ups and compete with it in another competition this year, wherever my job hunt lands me. Butcher took very little damage, only scraping some of the paint off of the weapon disk and blowing a drive motor. These are easily fixed and it will be ready to go in the future.
It was a bit of a mad rush in the last two weeks to get everything ready for Motorama. There were stressful and frustrating times. But in the end, everything is finished, on time. And I even had a little extra time to add some paint to make them look a little better this year.
With it now being February, Motorama is only 2 weeks away. I've been working hard over the past few weeks, but I still have a lot to go. Now begins the mad rush to finish everything in the next two weeks.
While not a lot changed appearance wise on Hercules, it has a lot of new little parts that need to be made to be able to make everything come together. I've made a lot of progress in the last two weeks, but there are still a lot of parts to be made.
El Tigre came together in the last two weeks. The main thing that happened was some weight reduction and adding traction compounds to the wheels. El Tigre is done for now, I might paint it later if I have time before the event. One down, two to go.
Butcher has been the slowest progress so far. I had issues with machining the body of the robot. I have to remake the UHMW bottom frame and spacer that connects the pulley and the weapon disk. I haven't done a lot on this since the last update, but once the frame parts are re machined most things should be easy to reassemble since most of the internals remained the same.
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.
As I post this, it is technically after Motorama 2018. And I never updated this before the actual event. But between school, traveling for sports, and rushing to finish 2 robots for the competition, finding time to update this website was hard. But now that the event is over I have a little more free time to archive my robotic escapades.
Before I start this update, I wanted to say thank you to all of you who read this blog. I originally started this as a way to archive my ideas and showcase my skills for future potential employers. That 3.5 years ago at this point. I still partly keep this blog updated for the reasons mentioned before, but it has become so much more popular than I had ever imagined (see image below). Looking at the statistics of all the people that read this and hopefully gain something from this blog makes it that much easier to keep this updated regularly. So thanks for reading.
This was the first time I had taken Hercules out of the box that I keep it in since Motorama 2017 when it barely won the ant weight division after two brutal fights with the horizontal spinner, Foiled:
The champ was looking rough. Very beaten up, but most of the core parts were in tact. The wheels were pretty chewed up. The wedge guards needed to be replaced. But all of the electronics and UHMW unibody were all intact and operational. The part that needed the most improvement was the lifter/clamp assembly.
I wanted to strengthen up the clamp assembly. My solution was to replace the 3D printed lifter horn with a piece of extruded T shaped aluminum. To go with this, I wanted to strengthen up the clamping arm too. Instead of the 1/8" UHMW shape, this version was to be made of the same 1/6" hardened O1 tool steel that the lifter plate is made of. Two matching pieces would sandwich a UHMW spacer. The geometry of the lifter was to be as close as possible to the past version because before it broke, it was very effective.
For those who haven't been reading some of the older updates I made about the design of Hercules, the idea is that is it was to be a combo lifter/clamper actuated by a single servo. Here you can see the up and down configuration actuatated by the servo on the right side of the pictures. The operation works as the servo turns, a connecting arm pulls on the back side of the clamping arm. When the clamping arm comes into contact with something, stopping its rotation, as the servo continues to pull on the assembly. With the clamping arm unable to move anymore, the geometry allows the servo arm to know pull on the entire lifting plate assembly and cause it to rotate. When the servo rotates back, it pushed the backside of the clamp arm down until it runs into the lifter horn, which in turn pushes the entire plate back down to the starting position
Below are some build pictures of making the new assembly:
Below are some pictures of the internals of the finished robot, and a close up of the finished clamp/lifter assembly.
Finally the robot was ready for motorama, thankfully there wasn't a ton to fix up. Because Butcher took all of the rest of my spare time up until the competition.
After Motorama 2017, Butcher had some problems that I wanted to address. First, the belts. I had been using green urethane variable length belting that at some point had failed in the majority of Butchers fights so far. In order to fix this, I wanted to get away from the urethane belting completely because the points at which you had to weld it together were such a big weak point that a number of the belts failed in spin up before it ever hit anything. The next major issue I wanted to address was spin up time. Butcher struggled to ever really get up to top speed. There were belt issues, but on top of that: the motor was under-powered for a weapon of this size, there was a lot of friction in the weapon assembly itself, and the entire robot was run off of 4s (14.8V) because the drive motors were only rated up to 12V and they were very unhappy above that. To fix this I wanted to use a bigger weapon motor and run the entire robot off a higher voltage to get more power to decrease spin up time. Because my current drive motors were only rated for 12V I'd have to get higher voltage rated drive motors. I had been wanting to experiment with using brushless drive motors for a while, they would give me better power for drive in a smaller, lighter package. They are also generally rated for higher voltages for their size. All of these benefits would enable me to more easily use the higher voltage battery and larger weapon motor.
All of these proposed changes can be seen in the pictures of the CAD model below:
With all of the CAD finalized, I had only a couple months to get butcher ready. Because I had a lot of other time commitments this was a very tight schedule. Because of this tight schedule I wanted to make sure I came in underweight so that I wouldn't have to do any emergency lightening of the robot right before the competition. As I replaced parts from the old robot I took note of their weight to make sure I ended up around the same weight as before. Below you can see the weight comparisons of some of the components:
The new top plates were cut out on a ShopBot CNC router that I have. The new pocketed design really helped to save some weight as did the new brushless drive motors. One of the problems with the old design I needed to address was the threaded inserts that I used to hold on the top plates pulled out in my last fight against Minor Threat 3. They were brass inserts that couldn't get enough bite in the UHMW to properly hold on the top plate. My solution was to replace the threaded inserts with steel binding posts, which should provide significantly more force to hold the frame together.
At this point I only had some minor machining work to do including boring out the weapon pulley, shortening the weapon motor shaft so it fit in the robot, and pressing some hubs into the new wheels to replace the old ones that god shredded. But the rest of the work to be done was mainly electrical.
I soldered everything together and played every roboteers favorite game, wire tetris, to make everything fit properly. Because, I never learn to leave space for wires in my designs. Everything looked good, but I still had to flash (reprogram) my speed controllers for my drive motors so that they would work in both directions so that I could use them for drive rather than the stock programming that would only turn them one way.
I used this super helpful video from Robert Cowan to reprogram my drive ESCs along with some help from some fellow builders who had a little more experience than I did to work out some of the kinks. All told it took a lot longer than I had anticipated and left my desk looking like this for about a week or two:
The night before I was set to drive to Harrisburg PA for Motorama Butcher was almost ready. I still had to reprint the weapon motor pulley because I had originally 3D printed it, but forgot to change the bore dimension, so it didn't fit over the motor can like I had intended it to. Notice in the pictures below that the belt isn't on because I woke up early the next morning to print the weapon motor pulley. More on that in the event report, but Butcher was as finished as I was going to get it at 3 am the night before I left for Motorama. It was underweight and drove around so I was happy with it.
In the rush in preparing for the event, I slacked off on updating the website in favor of actually getting my robots ready for the competition. So here is what happened in that last week leading up to the competition:
When I last posted, I had blown the weapon ESC on Butcher. I got a replacement, the TZ85 from Hobbyking to handle the current a little better. This still caused some start up issues with the motor, so I decided to drop back down to my 4S LiFe batteries instead of the 6S LiPo that I had in there in order to avoid frying the motor or controller if it stalled on start up.
Now all that was left was to play some wire Tetris and squeeze everything back into the robot.
With that done. I had two days to pack up everything in preparation but I was ready for Motorama:
There were a total of 45 1lb antweight robots in the tournament this year. Double the number that were at Franklin Institute or Moto 2016. This made for a huge bracket and a long road for anyone hoping to grab first place. Hercules got a bye in the first round. Meaning it would have to win 6 fights to win it all.
Fun-Sized was a small drum spinner that Hercules faced in it's first fight. Hercules controlled most of this fight. The new grabber attachment allowed me to actually grab onto Fun-Sized's drum and push him around. He did get in a few good hits that eventually flipped Hercules over, but I won on a judges decision.
Viciously Circular is a vertical bar spinner, and Hercules's second opponent. This normally would be a bad matchup for Hercules as a big vertical spinner is likely to warp the lifter plate. After some dancing around there was one huge hit that left VC not spinning. Hercules got to show of its lifting skills by picking up and driving VC around the arena. Hercules won by tap-out to save VC's driver the embarrassment. I had hardened the lifter plate before the competition this time and it held up much better than the previous iterations after taking direct hits. There was only a few scratches and a small nick missing out of the plate after two fights.
Swamp Woman 2
Swamp Woman was a saw blade undercutter. This would be my toughest opponent so far. The large saw blade made it difficult to grab any part of SW without getting torn up. About half way through the fight he took out the 3D printed horn on the lifter plate of Hercules. But I out drove him for the majority of the match and won on a judges decision.
Hercules was a little chewed up. The wheels held together pretty well since I had put some silicon on them to add extra traction. The lifter horn was busted but I simply had to swap that out and it was good as new.
Discharge was a tough 3D printed, steel covered wedge robot. Unfortunately for him, it had been a little beaten up and I was able to get underneath of him a few times and control him. He got a few good shoves in but Hercules ended up winning on a split decision.
Foiled is a really interesting design. It uses a 3D printed, carbon reinforced hub on its weapon blade. This hub is shaped like a propeller such that when it spins, it provides extra down force to the robot. The downside of this is that there is less overall weight on the wheels, so it is very difficult to drive. I had to be very cautious of the powerful blade, but I managed to flip him onto his back a little over half way through. Because Hercules is so flat, I was able to squeeze under the disc and push him into the walls, sending him ricocheting around the arena. With an easy judges decision, Hercules was onto the finals!
Foiled won its way back through the losers bracket to make it to the finals to face Hercules again. This match went a little more evenly. Hercules took a lot more damage this time around. But I did manage to flip him over at the last second. The split decision went to Hercules, meaning Hercules went a perfect 6-0 to win 1st place overall!!
Overall I am super happy with how Hercules held up in this event. The UHMW unibody is a beast at absorbing impacts. I need to replace the wheels, wedge guards and lifter plate, but beyond that there isn't much else to do. I need to strengthen the servo mount I made and do something with the lifter horn to make it less prone to snapping off, but Hercules is still looking pretty great.
There were a total of 58 Beetleweights and 72 12 & 30 lb robots registered for Motorama this year. With the huge turnout they split up the Beetleweights into their own arena for the weekend. There were lots of very powerful spinners this year so it was going to be a tough road for anyone to get through the tournament alive.
Butcher's first opponent was Nothing Special. A fast wedge that was nothing special. Butcher got in a few good hits and then broke its belt leaving it weaponless. Nothing special got underneath Butcher and pushed it around a little until Butcher became high centered on its own belt. One disappointing countdown later and Butcher was in the loser's bracket.
Shake was a front hinged lifter that Butcher faced as its second fight of the day. This fight took way too long to get ready. We both had to use a postponement. I broke my removable link when I plugged it in for our first try and his left side of his drive train wouldn't work the second time. The third time around we had to make it work. Butcher got in a few good knocks and ended up seizing up Shake's drive for a knockout.
Army ants was a multibot consisting of 4 3lb "D2" kits. These kits do really well in the beetleweight class, but didn't fare so well in the hobbyweight division. Each bot was driven by a child of another builder. They all got destroyed but they had fun so I didn't feel too bad about it.
Minor Threat 3
Minor Threat 3 is a very powerful vertical spinner. I knew this was going to bee a tough match. Butcher had been having issues throwing belts so I had to only run the weapon at about half throttle. The plan was to attack the front right corner because I had a much bigger reach than he did. That worked for about 15 seconds until I hit the ceiling.
Butcher lost the belt and took some pretty nasty hits. But stayed together. I think the reason it didn't drive upside down is that the bot was getting high centered on the removable link. I plan on rewiring the whole bot with silicon coated wire to help prevent the solder connections from snapping under big impacts. Another improvement that needs to be done is to replace the threaded inserts with real nuts. The inserts held together for a while but stripped under big impacts because they are made of brass. Finally the biggest change I'll need to make for next time is to switch from urethane belts to a 2L V belt. I was prematurely knocked out of both of my losses due to a belt failure. That needs to be fixed for future version.
So I've been pretty busy lately and kind of forgot that I had a website. After Franklin Institute I had to get back to reality for a while and catch up on the things I had been putting off and building robots instead. I recently started a new Co-Op job though which means I no longer have homework for the next 8 months, so I have so much more time for activities.
My father and I plan on making our annual pilgrimage to Harrisburg, PA next week for Motorama 2017. This is set to be the largest Motorama yet with almost 200 robots registered! Because of the massive number of robots registered, unfortunately the beetleweight class filled up meaning I won't be bringing Barrel Roll. But that's okay, I didn't really want to have to rebuild that right now anyway.
This meant I had two bots to get ready, Hercules and The Butcher.
Hercules had almost nothing to fix after Franklin. The gears in the servo were stripped so I swapped that with a fresh one. The wedglet guards were a little dinged up so I made new ones. But spending half a day on getting a robot ready didn't feel challenging enough. So I went back and looked at the model I had to see if there was anything I could do.
I completely forgot that I had changed the model of Hercules already. I was really inspired by a similar robot, Flex. I decided to make a removable grabber attachment for Hercules. The idea is that as the servo pulls on the short side of the grabber making it rotate. When the grabber comes in contact with the top of another robot this locks the rotation of the grabber. The servo then continues its rotation pulling the lifting plate up.
This required making some specialized 3D printed parts:
From the top around clockwise we have a guard to prevent the wires from getting into the weapon motor on The Butcher, the lifter horn for Hercules's grabber, a new weapon motor pulley for The Butcher, and a servo holder for Hercules. I forgot to take pictures, but the grabber parts were just cut with a box cutter out of UHMW sheet and trimmed up on a belt sander. Here is a picture and a video of the finished product:
You can see that when it grabs something the weight is just a little too far forward that I don't have total control. I'm going to see if I can install some magnets underneath to help with traction on the steel floor of the Motorama ant weight arena.
Since the Butcher went undefeated at Franklin Institute, there were no structural parts that had to be redone, but the electric components were lacking. I didn't take many pictures of the build because I can't solder and take pics at the same time, but here is what the updated internals look like:
I upgraded the drive motors to Banebots RS540 motors, changed out the A123 LiFe battery packs for a single 6s LiPo pack, and changed the weapon system to a Turnigy Aerodrive SK3 1050kv outrunner driven by a Aerostar 70A ESC. Unfortunately this didn't work out so great.
While the drive motors worked much better, the weapon system stalled out. I tried to change the start up settings to see if it could manage and ended up catching the ESC on fire. Oops. I have a new one on order, but with only 9 days until Motorama, I need to get this fixed quickly.
Now that Franklin Institute is over and my life has settled down a little I figured I'd give an event report of how I did at the Franklin Institute event this past weekend. There was a huge turnout this year, with over 80 bots registered across 5 different weight classes it made for a crazy one day event. I had some ups and downs at the event but overall it was great fun as always.
Hercules vs Angry Erector Set
Hercules's first fight was against a horizontal spinner that was made out of some sturdy aluminum channel and had a FingerTech Chipper blade as its weapon. Hercules tanked a lot of the hits and flipped AES a couple of times. Half way through the lifter got stuck in the upright position. I out drove AES to win a judges decision. Unfortunately the reason that the lifter was stuck in the upright position is that the servo for the lifter had become dislodged and partially stripped the gears only allowing the lifter to go up and not down. Meaning for it's next fight I only had one lift before I was forced to rely on my drivetrain to win the fight
Hercules vs The Cuban
Because of the large number of competitors at the event, Hercules had about 5 hours in between its first and second fight. It's next fight was against a horizontal midcutter. At the start of the fight I rushed across the box to try and prevent The Cuban from spinning up. After some grappling and a couple of blows back and forth the belt came off of The Cuban allowing Hercules to win a judges decision using its one good lift to carry The Cuban across the arena and slam him into the wall.
Unfortunately this would be the last fight for Hercules. This fight didn't start until 6:30pm. Being that I had been at the museum nearly 12hrs at this point and was running on less than 5 hours sleep I was exhausted and decided to forfeit the rest of the matches and go home to get dinner.
I'm excited about how Hercules performed. I only have some minor things to fix for the future. It needs new wedge guards which is necessary after almost every event anyway. Since it's 1oz underweight I may make some out of steel next time to make it even sturdier. I plan on 3D printing some sort of servo mount to hold the servo in place better than the tape I have been using. I hopelfully will get around to making a tougher lifting plate this time. Whether that's out of titanium or heat treated steel, either of which will likely require stronger hinges rather than the hardware store ones I have been using. Other than that Herc is ready for it's next event since it took very little damage this time.
Oh Barrel Roll, why do you hate me. I had such high hopes for you this time. I had worked out all of your electrical gremlins. Everyone loves how you look. You have so much potential and fail every time. Before it even fought it had weight issues. I forgot to weigh it before leaving for Philly and had to change the front wedge to get down within the 3lb limit. And it only got worse from there...
Barrel Roll vs Mondo Bizzaro
BR's first and only fight of the tournament was against Mondo Bizzaro, one of the newest incarnations of Weta kits from kitbots.com. I never really realized how massive these things are. Barrel Roll is very dense, being made from all aluminum with a large steel wedge up front. Mondo Bizzaro dwarfed BR in comparison. I was confident going into the fight. I finally had control over my bot for the first time at an event. The fight started, we both rushed at each other. Mondo got under Barrel Roll and flipped it onto its back. In the process of trying to flip it back over Mondo Bizzaro got one good hit on the back corner of Barrel Roll and that was it. I lost all control of the bot. It was dead. I tapped out, defeated. Taking BR back to the pits it was pretty obvious what had happened
That one big hit from Mondo had bent the bottom plate enough to dislodge the wires that ran from one side of the bot to the other. The wires were loose enough to get caught in the weapon and be completely pulled out of the bot (see above right). This broke multiple wires and tore many others. With 2 other bots in the competition and the fact that I would essentially have to rewire a bot that took me 2 hours to wire in the first place, I would have to forfeit.
Barrel Roll is gong to have to get a redesign. I have been babying this original flawed design for too long. I will likely have to remake all of the body rails. The new one will have more space for the internals this time around because that is what has been causing all of BR's issues so far. I have plenty of ideas to work on for now including ways to keep the wires in check and reduce the weight so that is no longer an issue. But for now it's back to the drawing board for this one.
Where Barrel Roll failed the Butcher succeeded. Although it didn't have the stiffest competition, The Butcher went a perfect 4-0 on 4 straight knockouts to win first place in the Hobbyweight class
Butcher got lucky in the tournament draw, but I'll take what success I can get. It did have a couple legitimate knockouts and no major issues which I am very happy about. Here is the only video I have so far from the event of the Hobby finals between the Butcher and a 4-day build of a wedge, Freshies:
As you may or may not be able to tell from the video, the replacement motor that I threw in there was still too small for the size of weapon I am running. It took forever to spin up to speed properly. But when it was spinning it delivered some solid hits. For the future I'll need to put a bigger motor and bigger weapon ESC in there to decrease spin up time. I'll have to take some weight out of the frame to be able to do so which shouldn't be too much of an issue. But for now I am extremely happy with how it performed, earning Connbots first 1st place trophy!
Today I wrapped up everything that needed to be done on the hobbyweight to be able to get it ready for Franklin Institute this Saturday. The new replacement motor arrived in the mail. After going through 2 hacksaw blades trying to cut down the hardened steel shaft and cutting a giant hole in the top plate of UHMW, all that was left was the final assembly.
All said the weapon motor is still a little underpowered so I'm going to have to take it easy on the throttle this weekend, but it's as complete as it is going to get and I'm really excited about its possibilities.
Finally. Here is the all important team photo of all three bots before they look less pretty by the end of the day Saturday.
There are only 2 days left until Franklin Institute. I have been rushing to try and get everything done for these bots (man is three robots a lot of work). Unfortunately in my rush I didn't take a lot of pictures but I'll try my best to remember and explain what has gone on in the past week.
Last time I posted here, the Butcher was mostly done. I machined some spacers for the weapon assembly out of some 1/8" UHMW I had lying around. That was all put together (with the aid/distraction of my dog) and all that was really left was to make a belt and do some testing.
I don't have any pictures of the belt, but let me tell you, it's not pretty. I went through a long trial an error process of getting the belt welded together properly so it wouldn't come apart under its own tension and getting it to the right length so that it didn't pull too hard on the motor but still had enough grip to spin the disc. I see now why some builders love this and others hate it.
With the new belt in place it was finally time for some testing. In drive testing I came to realize that the bot seemed sluggish. It was only upon further investigation that I learned that the built in mixing in my Spektrum Dx5e transmitter limits the fwd/rev channel to 70% of full throttle. Without time between now and the event to get a proper mixer it will have to do. Next was weapon testing, which went even worse than drive testing...
In a big puff of white smoke I blew the windings on the weapon motor. Apparently it was not rated for the 4s LiFe I was running it on. With little to no time between now and the event I'm going to have to find a bigger replacement motor at a local hobby shop or else I won't be able to compete.
Jumping ahead a little I did some post machining on the drum for Barrel Roll. I reamed the center holes for bearing and countersunk the holes for screws to fit in. I took some time procrastinating doing homework to add some flair to the weapon discs with a little red paint. Updated pictures of Butcher will come later after I get the new motor. But for now here is how the updated Barrel Roll looks.
I think it looks awesome. That new disc is way more balanced than the one that I made in the wood shop in my basement. It should do some real damage this time around. The bearing that I added to the ear makes it so much easier to drive upside down and allows BR to self right like it was originally designed for.
With Barrel Roll complete and Hercules being done for some time now I am 2/3 bots complete for this weekend. Barring any other major issues I should be able to get ready in time and have a great competition.
My name is Michael Connerton. I recently graduated from Case Western Reserve University with a master's in mechanical engineering with a focus in robotics. This blog serves as a record of my exploits into the world of robotics and especially combat robotics.