Author Topic: Ry's Philosophy for High End Combat Robot Design  (Read 2784 times)

Offline Ry_Trapp0

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Ry's Philosophy for High End Combat Robot Design
« on: November 07, 2017, 02:28:50 AM »
...yes, it's that time of the year again, everyone! Time for Ry to show up for a few weeks before inevitably disappearing for about a year after life distracts again! This time, I lend my pseudo-intellect to the world of combat robot design! While I've personally only screwed around with hack job hobby grade bots built out of RC parts and that have never seen legitimate competition(just fun with friends), I do have a decent amount of history in amateur & professional auto racing(even worked for Michael Shank Racing, a professional road racing team that won overall at the 2012 24hrs of Daytona[of course, I only worked for them for the '11 Daytona 24 *KILL ME*] and is currently Acura's factory team, racing the new Acura NSX in IMSA competition) where ounces count, cutting edge composites & mechanical designs are developed & utilized, and where stresses are MAGNITUDES greater than anything seen in robot combat, plus some maintenance positions at a few manufacturing facilities that have necessitated the use of my fabrication skills, not to mention the work I've performed on my own cars & bikes(like rebuilding the engine of my '81 CB650), so one could say that I have a large amount of indirect experience that is applicable to the limitations & necessities of combat robots.

And so, with my nephew having recently gotten his license(...it's ****ing with mah head, man - I ain't THAT old, I swear!), a job, and expressing interest in building a robot, I decided to organize my thoughts & opinions about combat robot design into an 'in general' detailed 'philosophy'(as much for myself as for my nephew), with a heavy influence from my experience in high end automotive racing dictating the minimum standards that I would expect of myself and my robot designs(and some around here know of my many unique concepts that I still believe are realistically plausible - I STILL want to build a real life 'Unlimited Limits'). Needless to say, it's a bit incomplete and a work in progress, but I thought some here would find my technical vomit interesting at least(get ready, she's a long one!)...

[note: this is biased towards the BIG weight classes, not hobby weight robots - weights & kinetic energy don't scale linearly thanks to physics, so many of these statements simply won't be true for hobby scale bots]


Design Goals


- Maximize simplicity vs benefit; if benefits of a system do not outweigh its complexity, reliability, or ease of repair, it should be redesigned & simplified
- Weight reduction; all possible areas while minimizing impact on strength & durability, and meeting target kinetic energy goals. Truss style lightening holes in structural components. All edges radiused. *Mass does NOT equate to strength - intelligent design & engineering!*
- Modularity; robot systems should be modular where possible, intelligently designed. Modularity should NOT take precedent over strength, durability/reliability, or simplicity, and should be applied where reasonable.
- Shock mounts; where possible, chassis joints/modules should be shock mounted to absorb as much energy as possible before it's transmitted to sensitive components. Intelligent design; shock mounting should NOT decrease mounting strength/durability to the point of unreliability.
- Minimal friction; high quality bearings and/or oil impregnated/self lubricating bushings in drive systems & weapon systems(high kinetic energy spinners should consider high quality bushings - significantly stronger & more reliable than the comparatively fragile bearings). Due to the lower RPM, drive systems can use dry bearings for ultimate low friction, but will have to be checked for play & replaced as necessary with regularity(not suggested for the high RPM[read: HEAT] of spinning weapons, should be cleaned & lubricated regularly for maximum efficiency, reliability, and life). Sealed bearings should not be used in combat robots, the seals significantly increase friction & are intended for extraordinarily dirty environments, such as industrial manufacturing applications
- Hardware; high quality black oxide(not stainless - susceptible to gulling, stripping) hardware is suggested in strength critical applications, raw graded hardware OK in all else. Thread locker(KNOW YOUR COLORS), antiseize, or locking hardware used on ALL fasteners, quality lubricant used on torque-to-spec bolts if used(critical for accurate torque - see: race engine building, lube used where a torque wrench is used). *NO HARDWARE STORE GARBAGE* graded bolts mandatory(better to 'waste' unnecessarily high quality hardware than cheap out and find out that you need it later - quality hardware is cheap insurance). Also, hardware should be sized for the application - BIGGER IS *NOT* BETTER. Gun drilling is possible for weight reduction with negligible affect on strength, titanium hardware is also a weight reduction option(and a wallet reduction method...)
- Minimize weapon reset/spin up time while still meeting kinetic energy goals. Applies to ALL weapons; spinning weapon spin up time, pneumatic/hydraulic weapon reset time, etc.
- Redundancy where possible. Multiple drive motors, or, for a spinner, multiple smaller weapon motors(w/ one way bearing/clutch systems) with individual electrical systems instead of a single large motor & electrical system.
- Cooling; heat sinks & airflow accommodations(venting, cooling holes, louvers  etc.)where appropriate, possibly cooling fans(high pressure computer fans are a cheap, lightweight, airflow optimized option). Given the ridiculous amount of robots that have LITERALLY went up in smoke in the two recent seasons of BattleBots, this MUST to be a design priority.
- Motor protection; clutch(slipper, centrifugal, etc.) incorporated into weapon drive to protect motors & weapon drive systems upon impact. Also applicable for high powered drive systems(Vladiator and similar). See hobby grade RC cars, go-karts and similar for examples of intelligent clutch systems that both transmit torque while protecting drive systems.
- Wiring; all joints soldered or positively connected via high quality multi-pin connectors. All wiring & connections should be securely mounted, nothing free or loose.
- Electronics; all electronics securely shock mounted, nothing directly attached to chassis/mounting module.
- Power transmission; over sized shafts on over sized bearings/bushings, all power transmission & idler shafts gun drilled chromoly steel or titanium. Power transmission shafts MUST be splined, double-D, hex, or similar - NO KEYS, WOODRUFFS, OR SET SCREWS, these are NOT designed for torque transmission/torsional/shear loads and WILL be a weak point(they are also not a reliable mechanical fuse either).
- Mechanical fuses; these are pieces of hardware within a mechanical system that are deliberately designed to fail above a specific amount of load(such as a shaft that is intentionally weakened by being necked down to a specifically calculated diameter that will fail after torque load surpasses a specific value), with the goal being to accept a minor system failure to prevent a catastrophic failure that will cost significantly more spare parts, time, and money. This should not be attempted without some sort of legitimate engineering oversight(with calculations to back up the intended goal) as this is a pretty simple concept that is extraordinarily complicated & difficult to implement. Without such oversight, it's extremely likely that one will either undershoot, creating an unnecessary failure that will likely cost a win or overshoot, in which case the fuse will never fail before the catastrophic failure that it's trying to prevent. There is NO margin of error here.

Robots CAN *NOT* be accurately designed on paper; do not spec out the largest motors, batteries, strongest wheels, thickest armor, etc. with the belief that your paper calculations  are accurate and will put you right at the weight limit - the many points mentioned above(hardware, wiring, heat sinks, cooling fans, shock absorption, etc.) *WILL* leave you desperately cutting weight in every area, resulting in a flawed robot. CAD designs that don't take the aforementioned into account will create the same problem. Unless you have a significant amount of experience in combat robot design, LEAVE WEIGHT TO SPARE, you WILL find ways to make use of every ounce under the limit.


Design Principles


Chassis
 - components assembled into individual modules
 - chassis formed by modules being interconnected with countersunk holes, tapped holes/rivnuts & screws, to ease chassis repairs
   - permanent joints should be attached with appropriate structural adhesives instead of welds(if budget allows) as this is stronger than any other method(including welding) and is lighter weight(see: pretty much every fully aluminum automobile on the market - adhesives replaced welding about a decade and a half ago)
   - each module intersection either solidly mounted or shock mounted¹
   - robot potentially completely reconfigurable into various designs - varying length, width, possibly even number of drive motors and amount of driven and/or total wheels(such designs must be impeccably designed & implemented or will likely be mediocre in all versions - advanced builders only, very risky)
  Material
   - Metal²
   - Composite²


Armor
 - armor shock mounted¹ to chassis where applicable
 - armor thickness dependent on location(important to maximize use of available weight limit)
  Style
   - conventional individual 'piece' armor with multiple mounting points, typically mounted directly to chassis
   - single/multi-piece 'shell' armor, indirectly mounted to chassis by way of some sort of strut system, possibly using 'leaf spring' type struts that could be preloaded against each other during attachment. Likely less reliable than conventional piece armor due to less secure mounting. Risky, could leave your bot nekid if mounting struts/attachment points fail mid match
   - combination shell + piece armor
   - special 'heat sink' style armor to slow spinners(?)
     - kevlar fabric attached beneath hard armor to "totally not entangle" spinners(?); obviously questionable legality("it's intended to stop piercing weapons!"), pretty damn expensive sacrificial armor, questionable effectiveness without testing, use at your own risk...
  Material
   - Metal²
   - Composite²


Drivetrain
 - independent drivetrain modules(see: Carlo Bertocchini's BattleKits for basic concept)
   - structure: heavy wall carbon fiber square tube or extruded aluminum for durability of module
   - drive: timing belt or motor mounted gearbox
   - highest quality ball bearings(ceramic?) where possible
 - drive & idler shafts
   - chromoly steel(4130), titanium
   - all shafts gun drilled
  Wheeled
   - two 4 wheeled modules or four 2 wheeled modules
   - wheels do not need to feature the same level of grip; a 4 wheeled robot can be designed to rotate around its front wheels by using lower grip wheels on the rear, allowing them to slide easier. This can be used as a method of tuning the drive
  Shuffle
   - composite(delrin?) feet, rubber coated/soled
   - with appropriate 'sole' material, can be one of the highest grip forms of drive due to the large amount of surface area compared to wheels while still allowing for very high speeds; great for pushers/rammers, as illustrated by Drillzilla/Dreadbot(the same robot, competed in 'Robot Wars' & 'BattleBots' respectively) before rule changes dictated that 'shuffles' didn't qualify as 'walkers'(which has, thus, made walking robots basically unfeasible - as it currently stands, no amount of extra weight will make them effective)
   - a form of drive waiting to be exploited that is constantly being looked past since most see them only as a former 'walker' exploit, overlooking the speed + traction advantages that they offer
  Tracked
   - a very advanced, complex form of drive that is very risky due to the difficulty of perfecting its design. A perfectly designed tracked robot can work as well as a well designed wheeled or shuffle bot, but anything but a perfectly designed track drive will inevitably lead to reliability issues that will leave you without propulsion, often times for reasons
   - heat treated chromoly steel or titanium treads are critical for a durable, reliable track drive, rubber coated/soled
   - also a very high grip option, dependent on the 'sole' material, due to the large amount of surface area compared to wheels


Weapon systems
 - independent weapon + weapon drive module
 - high quality bearings in drive system, oil impregnated brass bushings in high load pivot points
 - all shafts gun drilled
  Static
   - Material: mild steel, chromoly steel, titanium, carbon fiber, kevlar
    Wedge/Scoop
     - integrated chassis/armor or hinged
    Rammer/Blade
     - integrated into chassis/armor or independently attached(removable)
  Electric
    HK¹ Spinner
     - 2-3 smaller motors, double voltage, with clutch/one way bearings
     - conventional disc/bar w/ SURS*
       - possibly 3 piece sandwich construction for simplicity of SURS*
     - capable of being mount vertical or horizontal
     - centrifugal clutch or slipper clutch
    LK² Spinner
     - conventional disc/bar
       -
     - hammer mill
       - spring loaded 'hammers'
    HK¹ Drum
     - 2-3 smaller motors with clutch/one way bearings
     - conventional w/ SURS*
       -
     - hammer mill
       - spring loaded 'hammers'
       - sandwich construction w/ large diameter hammer pins supported by bushings
    LK² Drum
     - conventional
       -
     - hammer mill
       - spring loaded
 
  Pneumatic 
    HP³ Flipper
     -
    LP⁴ Flipper
     -
    HP³ Axe
     -
    LP⁴ Axe
     -

  Mechanical
    SE⁵ Flipper
     -
    SE⁵ Axe
     -


Electronics
 - electronics mounted in independent module
 - individual multi-pin connectors for wiring of each module(combining wiring of each module into individual wiring harnesses), using Weather Pack connectors or something similar
 - electronics & batteries shock mounted
 - resettable breakers on all module circuits, no fuses
   - solenoids to reset breakers during match?
  Speed Controllers
   -
  Batteries
    Drive
     -
    HK¹ Weapon
     -
    LK² Weapon
     -

Miscellaneous


 - heat sinks & ventilation for all motors, batteries, and electronics, possibly fan assisted cooling using computer fans
 - countersinking/flush fasteners where possible
 - drilled & tapped connections where possible/minimal use of nuts

* SURS - Spin Up Reduction System, sliding weights integrated into spinning weapon, spring loaded towards center mass to maintain greater weapon weight(kinetic energy) while reducing spin up time by tuning the sliding weights by operating RPM(the higher the RPM required to move the sliding weights, the quicker the spin up)
¹ HK - High Kinetic energy, weapon system 1/2+ of total weight, slower spinup, heavy impact - Nightmare
² LK - Low Kinetic energy, weapon system less than 1/2 of total weight, quick spin up, smaller impact
³ HP - High Pressure pneumatic, damage oriented - The Judge, basically anything from Inertia Labs
⁴ LP - Low Pressure pneumatic, point/control oriented -
⁵ SE - Stored Energy, spring loaded weapon for example


Thoughts, explanations, reasoning

Shafts
  - Gun drilling - the root or center of a shaft contributes very little to torsional strength while generally being the initial point of torsional failure(the material shears at the root/center, with the initial crack working its way outwards at 45 degrees across the width of the shaft, as shown HERE); gun drilling significantly improves strength-to-weight(reduces weight significantly while having negligible affect on strength), 10% reduction in strength 25% reduction in weight rule of thumb, improves strength to yield(allows greater degree of twist before shaft yields - yield is the point at which a material will no longer spring back, its strength falling off a cliff), reduces rotational mass. Not meant for pins in shear or bending, reserved for torsional applications.
  - Splined, double-D, hex, or similar - keys & set screws are used to locate components on a shaft, they are not designed to transmit torque(support shear/side loads), which is why they're known to fail when used in such an application. Splined shafts are generally stronger, with the greater the number of splines always being stronger than larger, low count splines.
  Proof of concept - see axle shafts in racing applications, such as high level drag racing, rock crawlers/rock racers/desert racers(Trophy Trucks)/Ultra4(combination rock crawler-desert racers), Formula 1/IndyCar, etc. You'll see gun drilled shafts with high counts of small splines(IMG of a BIG gun drilled 40 spline axle shaft from a Trophy Truck - note that the outside diameter is SMALLER than the diameter of the splines, this is actually stronger than if the shaft was the size of the splines because it removes the stress risers that are created at the splines, and it also reduces a little more weight. Also note the size of the gun drilled hole, that has little overall effect on torsional strength, believe it or not - *'CAUSE SCIENCE!*)

Timing belts
  - Positive engagement of drivertrain, not dependent on friction
  - Torque/shock absorbing properties with very high durability(high stretch before failure), limits the amount of abuse drive motors receive
  - Lighter total weight than chain drive, significantly lighter than gear drive

...TBC...



...there you go, guys. Like I said, it's incomplete, a work in progress, and certain sections I simply need to do a little more research on before adding my thoughts, like batteries & electronics. My knowledge of those dates back to the original BattleBots, so, to me, Victor 883 speed controllers are the sh**! Lol, but, given how many robots have gone up in smoke lately, I'm inclined to say screw the 'latest & greatest s00per d00per advanced' electronics, and stick with that old school stuff - because, assuming they're still available, there's no reason that they couldn't still work perfectly fine AND they've seemingly proven to be significantly more reliable than whatever has been letting the smoke out lately. And, call me old fashioned, but, regardless of what's available today, I would much rather control a high powered spinner with a good ol' solenoid. They don't necessarily need advanced control, solenoids are dead nuts reliable, and they can transmit truck loads of current & voltage without breaking a sweat.
I also can't see a legitimate argument for hydraulically controlled anything in an intended competitive robot, there just aren't enough readily available small scale hydraulic components that are designed for the pressures necessary in this sport, and the most successful example, the 'Robot Wars' halo bot, Razer is pretty well known for operating at pressures WELL exceeding what was actually legal in RW(don't confuse 'Robot Wars' for a fair, legitimate competition, guys, there's a LOT of 'pro wrasslin' going on in what was an entertainment biased TV show first, competition second...).
Also, note that the 'HK/LK' comments about weapon weight vs robot weight, the '1/2 total weight of robot' remarks are pretty much place holders at the moment, more research necessary to determine how much of the weapons system weight the "typical" high kinetic energy spinning weapons take up(not to mention a high energy drum system will require less weight than, say, a Nightmare-esque all offense vert spinner) - definitely open to advice here.
You'll likely notice that some of my superscripts are off as well, again to be corrected in future revisions.

Thoughts, comments, opinions, pure hate, post it all below, I'm curious to hears some thoughts. Mind you, these guidelines aren't mandatory for a GOOD robot - the vast majority are using Home Depot grade hardware, most aren't modular, most aren't using any kind of shock mounting anywhere(I'll expand on that later with some CAD screen shots), basically no one is gun drilling shafts(EASY weight savings - c'mon people, use your noggins!!!), so on and so forth, but IMO it's these details that can separate a GOOD robot from a GREAT robot(think Team Whyachi or Inertia Labs stuff - that's about as high end, well engineered, impeccable fit & finish as it gets!). Delusions of grandeur I'm sure, but, if I aim high enough, my failure should leave me somewhere around 'average', right? right???
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Offline Badnik96

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #1 on: November 07, 2017, 03:56:59 AM »
holy sh** ry trapp where the **** did you come from

Offline Philippa

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #2 on: November 07, 2017, 04:59:59 AM »


Damn.

Offline FightingBotInformal

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #3 on: November 07, 2017, 06:28:44 AM »
i swear to god i wonder why ry hasn't been given vet rank yet.
my weeb headass with my anime avatar is gone

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Offline Pwnator

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #4 on: November 07, 2017, 06:41:11 AM »
i swear to god i wonder why ry hasn't been given vet rank yet.
Because his last post was 11 years ago and was basically forgotten. Moreover, rank updates are always done in batches unless it's for staff. So swearing to god won't do much when you don't have common sense.
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Offline Mystic2000

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #5 on: November 07, 2017, 06:48:24 AM »
jesus **** someone's not screwing around, if you manage to follow that i'm pretty sure you'd be managing to do some pretty good sh**, also IRL Unlimited Limits => YES
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Offline Sylandro

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #6 on: November 07, 2017, 02:54:23 PM »
holy sh**
Quote
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Offline Mr. AS

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #7 on: November 07, 2017, 10:29:29 PM »
didn't read lol
How you make Alarm Clock Pizza is:
Step 1: You buy an alarm clock from the store, and then you have to break it and put it in the sauce.
Step 2: Fold the sauce in 5 slices and put it in the dough.
Step 3: Paint the eggs with a pitcher of a clock showing what time you want to wake up and eat pizza for breakfast.
Step 4: Put the eggs in the dough.
Step 5: Make it flat into a round shape and draw the time you want on it.
Step 6: Put some old steel to prevent other peple from stealing it.
Step 7: Make it flat and cut into 60 slices 1 for each minute in 1 our.
Step 8: Put in the oven set the timer to 30048813.2884 seconds and put the temperature on 'Volcano' setting.
Step 9: If you think it is take to long, then get yor alarm clock and set it to now so that it will ring and you can take it out.
Step 10: Take it out uv the uvin wen it is redy and go to bed. In the morning eat pizza and also eat yor hands bi mistake.

Offline yugitom

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #8 on: November 08, 2017, 03:40:27 AM »
Screenshot 2017-11-08 at 09.37.22.png

Nothing to do with the thread but I find this genuinely amazing. We just need Dino Venger to come back, now.

Offline doot

Re: Ry's Philosophy for High End Combat Robot Design
« Reply #9 on: November 08, 2017, 05:45:21 AM »
Its even more shocking to know that one of the oldest ever GTM members (in terms of first registration, anyway)  has returned after over a bloody decade. That's older than even some of the members here!

Oldboi-isms, aside, I like what you've got listed in this post! Its definitely a massive textwall, but the ideas you have there are neat-o.

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #10 on: November 08, 2017, 06:33:38 AM »
i swear to god i wonder why ry hasn't been given vet rank yet.
Because his last post was 11 years ago and was basically forgotten. Moreover, rank updates are always done in batches unless it's for staff. So swearing to god won't do much when you don't have common sense.
:claping
im just waiting for meganerdbomb to come along and kick things into gear.

Offline cephalopod

Re: Ry's Philosophy for High End Combat Robot Design
« Reply #11 on: November 08, 2017, 06:34:25 AM »
Would be interested to hear your take on the increasing usage of plastics in combat robots!
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Offline Ry_Trapp0

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #12 on: November 09, 2017, 11:07:04 PM »
i swear to god i wonder why ry hasn't been given vet rank yet.
Because his last post was 11 years ago and was basically forgotten. Moreover, rank updates are always done in batches unless it's for staff. So swearing to god won't do much when you don't have common sense.
Well my last post most certainly wasn't from 11 years ago, it was actually from some time last year when I made a generic "remember me" thread where a few of us old folk popped up to talk about being old. There were a few heres and theres before that as well(curiosity about RA3, followed by complete & utter disappointment just like everyone else), I've made a handful of posts a year for the past however many years, though, where those posts have went, I don't know.
But it's whatever, I'm not here for ranks, tags, recognition, or anything like that(though I certainly appreciate that some would suggest such things for me), just here to shoot the sh** so to speak. I begun compiling this concept after my nephew expressed interest in putting a robot together(it felt pretty cool that he was watching a new BattleBots season and gaining an interest around the same age that I did when the original series ran) and wanted to get some feedback from others that I had a vague relation to and that at least have a little interest in the topic, and so here we are.


jesus **** someone's not screwing around, if you manage to follow that i'm pretty sure you'd be managing to do some pretty good sh**, also IRL Unlimited Limits => YES
I should probably clarify that this isn't an 'all or nothing' kind of list or build philosophy. We likely won't consider even ordering parts for 3 months, 6 months, some short-mid term period of time(gotta build up funds, come up with a rock solid game plan to minimize waste since sponsorship isn't a legitimate hope compared to the 'golden era' of robot combat, putting a few ideas together in CAD and settling on a design, so on and so forth), and, whenever we get around to putting actual tools to material, it's probable that I'll break some of my own rules here. For example, the first build probably won't feature individual modular assemblies of components(all batteries mounted together with a single quick connect to the other assemblies, the electronics on their own module with single quick connect, drivetrain in their own modules, etc.), even though that's something that I believe is pretty critical in today's competition to maintaining consistent performance over multiple violent rounds(it's incredible how much more powerful & destructive today's robots are; who knew that the kinetic energy of Ziggo would become almost standard!).

But, yes, as far as I'm concerned, a robot designed & built in a way to meet each of these points would be the gold standard of quality and functionality among combat robotics, and so my goal will be to meet as many of these as I possibly, reasonably can. I'd also like to point out that the majority of these points are focused on rational, logical, well thought out design, and that one doesn't need to spend excessive cash to follow most of these concepts. There has always been this problem(IMO) in robotics where these builds are seemingly always approached as one big picture design, with the goals to build the thing that these people picture in their heads. This is completely backwards - quality design begins from the inside out, and, if you focus on each individual detail, the end result will be an impeccable design that essentially builds itself(if you focus on the quality of the details, you will achieve a high level of overall quality by default - you can make a poorly designed/built robot appear to be higher quality, but you won't need to fake it if quality begins from the smallest fastener all the way through the highest end component).

I picked up this sort of mindset after being involved in the aforementioned 24hrs of Daytona winning professional race team, wrenching on hot sh** like this...


(seriously not bragging - this sh** is so cool I can't help but post it up!)


[ Quoting of attachment images from other messages is not allowed ]
Nothing to do with the thread but I find this genuinely amazing. We just need Dino Venger to come back, now.
Ha, that is fascinating


Would be interested to hear your take on the increasing usage of plastics in combat robots!
Warning you now: you brought this text wall on yourself!

I'm going to read 'plastics' as composites in this instance, though there are MANY more useful materials than just the typical carbon fiber & kevlar style products. Anyone that isn't considering extensive use of plastics in their builds is likely a little too 'old school' minded for today's competition and is likely leaving a LOOOT on the table. It's kind of hard to argue against the standard metals as primary armor due to the balance of price, availability, consistent quality, ease of use(you don't need to wear a respirator when cutting it due to carcinogen concerns like you have with carbon fiber for example), and especially durability/resiliency(very different from 'strength', and the main feature that makes steel such good armor to this day) & mode of failure.

Now, when discussing armor in robotics, we're basically referring the stuff that these bat sh** crazy spinners is going to be destroying - the other weapons are primarily focused on winning the points battle or incapacitation by internal failure(electronics, wiring, chassis/drivetrain failure, etc.) - so the primary concern of armor is absorbing these incredible amounts of kinetic energy while minimizing the total size of the affected area & total loss of armor after impact. That's why, say, carbon fiber(or any other composite) just isn't as good of a choice against a Tombstone as steel is - what's going to happen is that, upon impact, the carbon fiber will absorb and redirect a significant amount of the energy, but it does so by essentially shattering into a massive amount of pieces(even into dust). This is GREAT for energy absorption, BUT it creates a new problem because the affected area is significantly larger than just the point of impact and this creates a gigantic hole in your robot - not good for further impacts obviously! Also, because this large area of your armor has practically vaporized, you have less armor(even if its damaged) to protect from further impacts, while a malleable metal will tend to tear in large pieces, but will often times still be attached. Although it's significantly weakened in this case, it's still advantageous to have something there rather than nothing.

The uses, of course, extend well beyond just armor, but I figured I should cover that first since that always seems to be the big questions - "Why don't you use s00per d00per magical carbon fiber for armor?". But composites are most advantageous when used for structural purposes. Now, if you're going to use composites in such a way(namely as a chassis material or high energy weapon structure), it's CRITICAL that you know what the hell you're doing. My history in the racing biz(as well as my own obsessive compulsive research) has given me a lot of hands on experience with laying composites, CF primarily, as well as context for when, where, and how you use them, and, if you don't have this kind of knowledge, you should stick to more standard materials that you're more familiar with, otherwise you're not only going to likely cause more harm than good, but you're going to do so while wasting LARGE amounts of money. For example, everyone knows that kevlar is a s00per d00per strong hardcore lightweight composite, right? I mean, it's bulletproof after all! Well, due to the structure of kevlar, it is ATROCIOUS in compression loads, which makes it a poor choice for, realistically, any real structural uses that aren't in tension where it's incredibly strong. Another example - fiberglass. Everyone knows that it's pretty awful compared to the standard high end composites like CF and kevlar, right? No, not really - the HIGH QUALITY off the shelf fiberglass fabric is actually higher in tensile strength than standard off the shelf carbon fiber, while offering similar compressive loading, suffering only a minor weight penalty(carbon fiber is pretty much the undisputed king of strength to weight).

Going beyond these uses for composites that are most familiar in robotics(armor, chassis), there are MANY smaller uses that, frankly, we don't see them used in enough. You can typically find examples of these in the hobbyweights(especially around the 30lb-ish range), such as using machined blocks of delrin(a fantastic material due to its unique pseudo-self lubricating properties) in place of bearings, bushings, and pillow blocks, or as chain guides in chain drives(no better material for that use). Most people tend to have a rather archaic knowledge of plastics that is pretty much on the level of "they aren't as good as metal but they weigh less". But, with the evolution of plastics since their inception and some of the recent breakthroughs over the last few decades, we are actually on the cusp of being able to have LEGITIMATE 'plastic engines' - there are actually available composites within the marketplace that can withstand the heat & friction of internal combustion piston engines. Not just that, but plastics/composites range from the softest, most malleable shock absorbing examples to extraordinarily hard, stiff offerings that are as structurally rigid as metals while offering a significant weight savings. So, needless to say, there's honestly no excuse for plastics/composites not being MORE common in combat robotics, especially given their toughness/shock absorbing properties. It's something that I would really like to take advantage of as a part of the above design principles.

Needless to say, I REALLY want this first build to feature a chassis that's made of carbon fiber square tube(how extreme do you want to go?), with specifically designed corner pieces & fishplates for attachment/reinforcement, relying on either adhesives for permanent joints or rivnuts(or something similar) for removable joints. It has the ideal properties and ease of use to create a very strong, resilient, lightweight, and easily repairable chassis structure, and square tube attached with screws + rivnuts will make modular design pretty easy. In fact, adhesive technology is advanced enough that one could even choose a relatively low strength adhesive to use in combination with bolted joints that would reinforce them while still allowing for the joints to be pulled apart(with, say, maybe a heat deactivated adhesive) without damage. With some of the brains in this sport, it just amazes me that we haven't really seen this easily accessible technology make its way into robot design.
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Offline cephalopod

Re: Ry's Philosophy for High End Combat Robot Design
« Reply #13 on: November 15, 2017, 06:20:35 AM »
A lot of combat robots now take full advantage of materials such as HDPE, UHMWPE, RG1000 etc so I had found it interesting that you had omitted them.
One rather high-profile example you could take of HDPE on modern bots is Gabriel - see here how though Carbide could take chunks out of it, the machine just kept going.

On our heavyweight for example, which is being built on a strict budget, we are using a few mm of stainless steel covered with a layer of thicker HDPE, allowing the HDPE to help dissipate energy before the weapon hits the steel, which is also far better in terms of puncture resistance.
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Offline Ry_Trapp0

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #14 on: November 15, 2017, 05:48:26 PM »
Honestly, I didn't really talk about modern plastics used as armor for a couple reasons - one, I just don't know enough about specific plastics and their use in that specific application to offer any comments that I could be confident in(it's better to not say anything than to prove your ignorance to the world...), and, two, this 'guide'(using the term VERY loosely here) is built around north american robotics where we see levels of kinetic energy in spinners that surpass what damn near any armor options are capable of coping with. Mind you, I'm not about to start an argument between north american robotics vs european robotics, but the rules, resources, and build philosophies result in clearly different styles of robots - NA bots aren't 'better' than euro bots because of the aforementioned points, and we really haven't seen truly successful examples of robots that have crossed over and legitimately competed successfully, they're just too different.

And, forgive me if that fight doesn't convince me to commit to full plastic armor on a more conventional robot(thwacks are certainly rare today and for good reason - they typically don't perform that well). The amount of deflection that was allowed by the design of those giant wheels was a significant factor in the survival against a solid spinner like that, but isn't representative of HDPE being much more solidly mounted to s rigid chassis where deflection will be much more limited, likely leading to gaping holes being ripped away, exposing the innards. Or, to put it another way, those wheels are an example of choosing the right material for the given job - but that doesn't necessarily mean that the same material is appropriate for a different application. And I'm certainly not trying to talk you out of using it, I really like your plan of multi-material armor, my point is more so that, while it definitely looks more viable in euro competition, I just don't think that it's as appropriate for NA competition, against the likes of Tombstone, Icewave, Warhead, Moebius, SOW, and so on. The amount of energy well exceeds the energy absorption properties of any typical armor materials in this case and the focus is more so on designing a bot that, as a whole, can survive a fight against these with no regard to the survival of the armor itself(excepting a few rare examples, it just isn't realistic).

tl;dr - context matters and this was written in the context of NA competition, my fault for not pointing that out. Regardless, thanks for the feedback, you definitely have me reconsidering my stance on armor(the more I think about it, the more I would prefer a heavy metallic armor around the perimeter with something like a UHMW or HDPE for top & bottom armor in an NA bot build).
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Offline cephalopod

Re: Ry's Philosophy for High End Combat Robot Design
« Reply #15 on: November 16, 2017, 03:57:22 AM »
For sure, Gabriel is an odd case (one worth researching if you haven't, the way it's built means that hammer actually has a similar power to some of the UK's hardest hitting axes and hammers) but use of plastics like HDPE is definitely on the rise, and it's hugely common for sub-HW UK bots to be comprised almost entirely of them. All my beetleweights are fully HDPE aside from front titanium wedges (right material for the right place as you rightly state :D) and none have been taken apart, yet.
Gathering parts for my first 30lb now and that will be completely plastic, but is a largely unconventional design so the need for those big, heavy metals is reduced considerably (if I had a picture of the design, all would make sense - alas I've made the conscious decision to not CAD this one)
I know this sounds like I'm trying to win you over but honestly it's nice to have a discussion about stuff like this with people who have different perspectives :P
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Offline Philippa

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Re: Ry's Philosophy for High End Combat Robot Design
« Reply #16 on: November 16, 2017, 07:35:26 AM »
Counterpoint to large scale plastic robots: Radioactive vs Tombstone, Frostbite vs Supernova. But yeah, in the lower weight classes I'm not gonna argue anything there, plastics can and will work pretty nicely in most places, it's been shown again and again and again.

Also, just speaking hypothetically here, wouldn't Gabriel still be skidding around if the wheels ended up in that shape regardless of what they were made of? If you took the same chunks out of the HDPE wheel, an aluminium wheel, and a wooden wheel, it'd roll the same right? (Also also, is there any layers of armour under the HDPE chassis of Gabriel that you can't see? If not then it's gonna be toast when a spinner gets to it.)

Offline cephalopod

Re: Ry's Philosophy for High End Combat Robot Design
« Reply #17 on: November 16, 2017, 07:46:49 AM »
I'm pretty sure, for your examples, aluminium would bend a LOT more, possibly also fracture, and wood would just splinter off in all directions, there'd be no wheel left. But I take your point.

Not personally sure on what's under the shell of Gabriel, I know there is at least a metal frame, unsure of whether this also translates to metal armour.
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