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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

June 2015

Walking the Walk

By |June 25th, 2015|Categories: 3D Printing, City Beest|

Bra man har bakgrunn i IT-bransjen. Jeg har lært meg at det meste som kan gå galt gjør det, men som regel kun i demonstrasjonssammenheng. Med dette i bakhodet, så sa jeg meg enig i at [...]

April 2015

Maker Faire 2015

By |April 11th, 2015|Categories: 3D Printing, City Beest, Götterdämmerung, Maker Faire|

Ser ut som om jeg kom i skade for å melde på en testprint fra Götterdämmerung II. Tror saktens vi skal få den til å røre litt på seg også. Sees på Maker Faire i [...]

February 2015

Götterdämmerung II – Enda mer testing…

By |February 20th, 2015|Categories: 3D Printing, City Beest, Götterdämmerung|

Usminket testprint av Dante, rett fra vaffelpressa. Modellen ble printet i 4 deler (mest fordi jeg ville holde mengden støttemateriale til et minimum). Dimensjoner: 29 x 30 x 26 cm. Printetid: ca 13 timer med 0,8mm [...]

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