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.