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City Beest

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Project Description

The CityBeest is a walking robot that consist of 377 3D printed parts. It has two independent crank shafts that are powered by geared DC motors. These are controlled by an Arduino. Ultrasound range sensors provide the robot with rudimentary obstacle detection capability.

The robot’s legs are based on the famous Theo Jansen linkage. Jansen’s 11 holy numbers were however not used as linkage parameters in the construction.

Instead, I decided to follow in Jansen’s footsteps.

A genetic algorithm was implemented, in as an attempt to search parameter space for other sets of viable numbers – numbers that would give rise to a viable gait for the same mechanical linkage. A mechanical simulation was used to calculate the trajectory of point “G” for a full rotation of the AB segment. Certain aspects of the shape described by the trajectory, such as “stride length”, “lift”, “linearity of ground stroke” were then calulated and used as input to the scoring function for the genetic algoritm.

The genetic algorithm evaluated approximately 12 billion parameter sets over the course of 10 days. Parameters for eleven of the discovered parameter sets  are listed in the table below.

Theo Jansen’s Holy Numbers

a b(CD) c(CH) d(CF) e(DF) f(FE) g(HE) h(EG) i(HG) j(BD) k(BH) l m(AB)
38 41,5 39,3 40,1 55,8 39,4 36,7 65,7 49 50 61,9 7,8 15

Visualization of the mechanical simulation used by the genetic algorithm, showing the Theo Jansen linkage, parametrized with set #11 (see the parameter table below).

Other “Holy Numbers” discovered by the genetic algorithm. (AC is Jansen’s a-l diagonal)

# CD CH CF DF FE HE EG HG BD BH AC AB
#1 98,20 141,85 121,95 205,30 198,21 177,96 208,04 243,82 121,46 244,44 155,25 41,19
#2 105,65 137,24 136,73 152,88 207,52 193,32 191,63 252,14 184,67 251,84 176,56 44,03
#3 137,97 127,07 175,22 169,76 201,50 166,52 233,41 179,55 194,50 238,89 162,49 45,54
#4 106,63 126,00 163,98 144,98 191,21 113,67 236,64 160,97 144,35 253,47 165,45 34,11
#5 152,19 180,78 150,44 175,17 194,29 122,51 185,10 203,64 206,66 254,17 111,53 25,59
#6 145,83 122,53 101,70 196,10 217,52 101,24 213,72 219,86 183,15 255,95 229,75 54,47
#7 141,72 156,33 94,95 170,45 155,37 84,62 200,61 161,12 167,11 243,68 148,88 53,01
#8 144,36 147,38 114,60 253,02 193,30 142,71 203,55 206,07 178,70 234,28 218,97 73,15
#9 140,24 102,10 196,13 131,76 221,74 152,14 247,01 176,00 212,53 223,31 170,67 45,16
#10 128,21 157,95 164,60 155,33 194,10 140,18 236,24 153,45 181,72 249,81 155,64 51,38
#11 158,58 190,15 159,66 174,83 197,86 137,28 251,18 180,12 206,22 248,52 131,11 56,04

City Beest infographics

Timeline

April 2016

Mobile Beer Platform – mk I

By |April 5th, 2016|Categories: 3D Printing, City Beest, Götterdämmerung, Robotics|

Sånn går det når man glemmer å slå av 3D-printeren sin i løpet av påskeuka. Før man vet ordet av det, så har robotene i kjelleren formert seg. Hils på skjelettet til MBP - mk I. [...]

October 2015

Maker Faire Roma 2015 – Retrospective (og et par betraktninger mht veien videre)

By |October 31st, 2015|Categories: City Beest, Maker Faire|

Maker Faire Roma ble i år arrangert for tredje gang, med over 100000 besøkende over tre dager. Jeg ankom hver dag ca 40 minutter før åpning, og da var det gjerne over 50 meter kø [...]

August 2015

Maker Faire 2015

By |August 25th, 2015|Categories: City Beest, Götterdämmerung, Maker Faire|

I helga braker det løs, og jeg har begynt å lage lister. Har hukommelse som en dement hamster og er totalt avhengig av å ha ting skrevet ned på papirlapper, hengt opp på strategiske steder. Skikkelig viktige [...]

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