Run Amok Combat Robotics
What Weapons Win -- Active Weapons versus Passive weapons -- 2016 update

In 2006 I ran a statistical analysis of combat robot tournaments for the prior year to compare the performance of robots with kinetic energy spinning weapons ('spinners') to other 'active' weapons, and to robots with entirely passive weaponry. The 2006 study found that on average robots with kinetic energy spinning weapons had a lower percentage of match wins and lower rankings than robots without spinning weapons, and that active weapons in general were less successful in these measures than were robots with non-active weapons.

There have been significant changes to spinner weapons in the last ten years: brushless weapon motors, exotic single-tooth disks and drums, and much higher kinetic energy storage. I decided to repeat my analysis with current data to see what effect these changes have had on actual match performance.



   Method

The 2006 study used tournament records for the 12-pound 'hobbyweight' and 3-pound 'beetleweight' class robots because they were popular weight classes and were commonly featured at tournaments. The beetleweight class has prospered and has 258 active and ranked robots listed at BotRank as of June, 2016. The hobbyweight class, however, has declined both in popularity and weapon diversity. The 30-pound 'featherweight' class has grown to exceed the hobbyweight class in the number of matches, the number of competitors, and the styles of weaponry represented. For these reasons I elected to replace the hobbyweight class with the featherweight class for the current study.

The number of currently active and ranked beetleweight robots (258) is an uncomfortably large group for this project. The previous study examined the 40 beetleweight robots that had competed at any of twenty tournaments held in 2005. The single largest recent beetleweight tournament at the time of this study (June, 2016) was the Motorama event held in February, 2016. A field of 38 beetleweight robots participated in that event, and I selected those competitors as my beetleweight sample for analysis.

The number of currently active and ranked featherweight robots (26) is a workable number for the analysis and compares well to the 24 hobbyweight robots used in the 2006 study. I used the entire group of active featherweight robots for my analysis.

For both weight classes I collected each robot's lifetime tournament record from Botrank.com on June 15th, 2016 and matched that data to weapon information from Builder's Database. Video from recent tournaments was used to supplement the weapon data where the database entries were unclear.

For purposes of this study, weapon categories are defined as follows:

1) A 'spinner' is a fully rotating kinetic energy weapon intended to damage the opponent by impact.

2) An 'active' weapon has a power source separate from the drivetrain and requires its own controlling radio signal.

Note that not everything that spins is a spinner, and not all spinners are active weapons:

  • A small rotating saw on an arm that decends to cut into an opponent is 'active' but is not an impact 'spinner'.
  • A dedicated 'thwackbot' that spins only by drivetrain power is not 'active' but is an impact 'spinner'.

The data for the two weight classes is summarized in the tables below:

 

Beetleweights from the 2016 Motorama Tournament
Name Wins Losses Rank Spinner Active
 Airhead 1 1 77 1 1
 Ami 0 2 213 1 1
 Barrel Roll 4 4 251 1 1
 BEST KOREA 10 7 35 1 1
 Crazy Monkey 2 0 43 0 0
 Deathcap 6 3 36 1 1
 Emmii 0 2 191 1 1
 Full Metal Breakfast 0 2 181 0 1
 Ghoti 2 2 94 1 1
 Hard Drive 2.0 2 2 75 0 0
 Margin of Safety 15 1 1 1 1
 Misti 4 1 28 1 1
 Mombot 2 2 103 0 0
 Mowbot 3 9 235 1 1
 Nocturne 2 6 248 1 1
 Project Darkness 13 4 8 1 1
 Quicksand 3 4 112 0 0
 Ravage 0 1 164 1 1
 Revenge of Dr. Super Brain 38 17 40 0 1
 Sandi 0 2 182 1 1
 Scrambles the Death Dealer 7 16 246 1 1
 Shelli 0 2 214 1 1
 Silent Spring 23 11 4 1 1
 Sloppy Seconds 2 3 113 1 1
 Son of Thunder 4 2 46 0 0
 Speed Wedge 3 17 4 5 0 0
 Super Veloce 6 1 18 0 0
 The Collective 10 10 175 0 0
 Thumbnail Not Available 1 2 115 1 1
 Thunder Child 11 14 76 0 0
 Trilobite 29 18 16 0 0
 Wedge of Allegiance 4 2 38 0 0
 Wedge of Destruction v3 1 2 176 0 1

 

All ranked Featherweights from BotRank (6/15/2016)
Name Wins Losses Rank Spinner Active
 Also Riptoff 3 2 6 1 1
 Big Black Richard 0 2 21 1 1
 Big Ripto 4 2 4 1 1
 Candy Paint and Gold Teeth 1 3 18 1 1
 Cathii 1 4 25 1 1
 Delta 0 1 17 1 1
 Derp3 0 2 22 0 0
 DrumThing Else 3 7 26 1 1
 General Lee 1 4 23 1 1
 Glasgow Kiss 4 3 5 1 1
 Gloomy 12 12 13 0 1
 Gracious Pipefessionalism 3 4 20 1 0
 Hyper Active 2 4 10 1 1
 megatRON 7 5 3 0 1
 Miss Fortune 1 3 19 1 1
 Omega 1 2 15 0 1
 PMTH 3 7 24 1 1
 Ruby Rose 1 2 14 0 0
 S.S. Impact 2 2 9 1 1
 Spur 1 2 11 1 1
 Styx 5 0 2 0 0
 The Magnificent Poncho 7 4 7 0 0
 ...Formerly Known as Drumthing 1 2 16 1 1
 Triggo 15 4 1 1 1
 Whammo 11 9 8 0 0
 Whammy Bar 1 2 12 1 1

 


   Results

Comparing the performance measures for robots sorted into weapon groupings of ['spinner'/'non-spinner'] and ['active'/'passive'] yields the following results by weight class:

Beetleweights Robots Mean Lifetime
Match Win %
Mean BotRank
[of 258]
Spinners 19 39% 129th
Non-Spinners 15 56% 84th
Active Weapons 22 39% 130th
Passive Weapons 12 61% 72nd
Only Wedges 10 65% 53rd

Featherweights Robots Mean Lifetime
Match Win %
Mean BotRank
[of 26]
Spinners 18 35% 15th
Non-Spinners 8 49% 11th
Active Weapons 20 37% 14th
Passive Weapons 6 49% 12th
Only Wedges 5 50% 11th
 

The bottom line is the same as it was ten years ago. In both weight classes the average spinner and the average active weaponed 'bot underperform their non-spinner and passive weaponed counterparts. Spinners trail in their percentage of matches won and in their scores at BotRank.

 


   Discussion

On average, active weaponry offers no advantage in combat success in weight classes examined. However, even though the average beetle or feather with an active weapon performs less well than the average passive-weaponed robot, the top-ranked robot in each of these classes is a spinner. If you have an experienced team with ample resources and will settle for nothing but first place you will be best served to run with a spinner. But if you're an average builder who wants to win matches you'll be better off building a boring but capable wedge.

 


   Questions or Comments

Email: joerger@toast.net


Copyright 2016 -- Mark Joerger, Team Run Amok

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