Strandbeest - Kinetic Sculpture

The Cantabrian Strandbeest

 

Introduction

Here we present a replica of the Strandbeest some of the students -including myself- studying the Science and Technology baccalaureate aided by the Technology professor, José Andrés Echevarría Zuazo, of the IES Ricardo Bernardo undertook. The brief given for the project was to create a, as stated, scaled down reproduction of Theo Jansen's Kinetic Sculpture.

A bit of background

Theo Jansen (born 1948) is a Dutch artist. In 1990, he began what he is known for today: building large mechanisms out of PVC that are able to move on their own, known as Strandbeest. His animated works are a fusion of art and engineering; in a car company (BMW) television commercial Jansen says: "The walls between art and engineering exist only in our minds." He strives to equip his creations with their own artificial intelligence so they can avoid obstacles by changing course when one is detected, such as the sea itself.

Our approach

It was chosen to perform the mock-up in aluminium as it is a cheap, easy to manufacture and light, very light material. Basically the raw material was purchased polished and extruded into a circular-O section. Also the 'eco' (using wind for instance) approach Theo chose was not shared, as it was decided that for the purpose of the José Andrés's lecture, a more mechanical aspect would suit best.
Once the direction we would face the task was established a initial broad illustration, of how the mechanism would work was created (see images). The most intricate problem, apart from achieving the desired motion, was getting all the tolerance values right, as it was a relatively large cross section, and required a pretty close tight fit if it was not desired for the structure to wobble.
Once the type of motion was determined the mechanism which was going to perform this had to be designed and constructed. The desired mechanism resulted in being a rack and pinion, where the second one was connected to a 10.8V DC motor, with a rotational maximum of 8000rpm, whereas the pinion was connected to the end 'legs of the beast' .
The previously referred to beast had a total of four complete legs which where composed of two individual structural frames joined together by a metal sheet, also had a symmetric opposite side, to grant further stability.
The most interesting part about the kinetic sculpture is how by using one simple electric motor it was possible to convert a linear motion -rack- to a circular one -pinion- and finally into a rotational one of the legs, but it is not any rotation as it has to rotate in half turns and sequentially -this is due to the fact that if independent movement of the legs and also movement as a whole of the body is desired; a half movement of one of the end legs and then the leg next to the other end. Therefore if the sequence is timed correctly a continuous movement is achieved.
Below have been detailed a couple of pictures where the students who created it, the professors and director appear, also a comparison between Theo Jansen's kinetic sculpture and ours, and Theo Jansen himself.