Thursday, 3 November 2016

Horse movement - example 2: Theo Jansen mechanism

simple design
a modified ratio of linkage and building of a wooden model (mainly for orientation about size)

basic trivia from WIKI: Theo Jansen (1948) is a Dutch artist. In 1990, he began building large mechanisms out of yellow plastic tubes (PVC) that are able to move on their own, known only as Strandbeest. The kinetic sculptures appear to walk. His animated works are intended to be a fusion of art and engineering, and he has said that "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 such as the sea by changing course when one is detected.

main page: http://www.strandbeest.com/
http://www.strandbeest.com/beests_leg.php
__________________________________

blog with a collection of content related to Jansen linkage (similar to this post here) - creator of this blog Joe Klan has also invented his own linkage which animate movement similar to spider. So blog is: mechanical spider




Jansen's linkage

From Wikipedia, the free encyclopedia

Theo Jansen's linkage. When the blue line at the right end of the picture is driven in a clockwise rotary motion, the leg (blue triangle at the bottom) executes a walking motion. Relative (dimensionless) proportions shown.
Jansens' Strandbeest
Theo Jansen's kinetic sculpture Strandbeest. A wind-driven walking machine.
The Jansen's linkage is a leg mechanism designed by the kinetic sculptor Theo Jansen to simulate a smooth walking motion[1] Jansen has used his mechanism in a variety of kinetic sculptures which are known as Strandbeests. Jansen's linkage bears artistic as well as mechanical merit for its simulation of organic walking motion using a simple rotary input.[2] Jansen's linkage is a robotic platform based on Theo Jansen's natural gearing mechanism. This work is focused in the design and development of the low cost robotic platform. The components used are readily available and inexpensive which makes it easy to build

Illustrations[edit]

Leg mechanism

From Wikipedia, the free encyclopedia
leg mechanism (walking mechanism) is an assembly of links and joints (a linkage) intended to simulate the walking motion of humans or animals. Mechanical legs can have one or more actuators, and can perform simple planar or complex motion.
Compared to a wheel, a leg mechanism is potentially better fitted to uneven terrain, as it can step over obstacles.[1]

Design goals[edit]

  • vertical speed as constant as possible while touching the ground (support phase)[1][2]
  • while the foot is not touching the ground, it should move as fast as possible
  • constant torque/force input (or at least no extreme spikes/changes)
  • stride height (enough for clearance, not too much to conserve energy)
  • the foot has to touch the ground for at least half of the cycle for a two/four leg mechanism[1] or respectively, a third of the cycle for a three/six leg mechanism
  • minimized moving mass
  • vertical center of mass always inside the base of support[1]
  • the speed of each leg or group of legs should be separately controllable for steering[2]
  • the leg mechanism should allow forward and backward walking[2]
Another design goal can be, that stride height and length etc. can be controlled by the operator.[2] This can relatively easily be achieved with a hydraulic leg mechanism, but is not practicable with a crank-based leg mechanism.[2]
The optimization has to be done for the whole vehicle – ideally the force/torque variation during a rotation should cancel each other out.[1]

History[edit]

Richard Lovell Edgeworth tried in 1770 to construct a machine he called a "Wooden Horse", but was not successful.[3][4]
The Plantigrade Machine by Pafnuty Chebyshev was shown at the Exposition Universelle (1878).

Gallery[edit]

Stationary[edit]

Walking[edit]

*4 legs6 legs
StrandbeestStrandbeest walking with four legs.gifStrandbeest walking with six legs.gif
GhassaeiGhassaei Beest Walking Paths traced.gifGhassaei Beest walking with six legs.gif
Klann linkage 1Klann Linkage Walking with four legs.gifKlann Linkage six legs.gif
Klann linkage 2Klann Linkage Walking with four legs - alternative measures.gif
Plantigrade MechanismPlantigrade walking 4 legs.gif

Complex mechanism[edit]

Shown above are only planar mechanisms, but there are also more complex mechanism:



- links on examples








TAKE ME U
more literature:













Tuesday, 1 November 2016

Horse movement - example 1: Warhorse & Handspring Puppet Company

The Handspring Puppet Company is a puppetry performance and design company established in 1981 by Adrian Kohler and Basil Jones. Based in Cape Town, South Africa, the company provides an artistic home and professional base for a core group of performers, designers, theatre artists and technicians.  Handspring’s work has been presented in more than 30 countries around the world.

The Handspring Puppet Company achieved critical acclaim when War Horse premiered in South Bank, London, on 17 October 2007. For this show, Kohler and Jones worked with directors Marianne Elliott and Tom Morris and choreographer Toby Sedgwick to design and construct life-sized horse puppets, controlled by three actors – two to operate the legs and one to control the head and neck, with all three actors providing a variety of sound effects. (from Company website - link is pasted below)



Team of creative personnel:
Puppet Design, Fabrication & Direction: Basil Jones and Adrian Kohler for Handspring Puppet Company
Adrian Kohler: Artistic Director & Puppet Designer
Thys Stander: Chief Cane Sculptor
James Dee: Factory Manager & Mech. Engineer
Jessica Mias – Jones: Asst Factory Manager & Puppet Maker
Simon Dunkley: Puppet Engineer
Andy Jones:Puppet Engineer & Supervisor
Phyllis Midlane: Fabric Engineer
Peter Collard: Puppet Maker
Ncedile Daki: Puppet Builder & Assistant Engineer
Kyle Daniels: Puppet Builder
Johannes De Lange: Puppet Builder
Luyanda Nogodlwana: Puppet Builder & Supervisor
Lyn Sieborger: Asst Puppet Builder
Zweli Ngcombela: Assistant Cane Sculptor
Phillip Roberts: Studio Assistant
Christiaan Johnson: Studio Assistant
Ntimpeba Epimac: Studio Assistant





Article: Engineering the movement
Photographs bellow are from the Handspring Puppet Company book (online version)







                                     






Sunday, 23 October 2016

Ljubljana tests II (October) - new type of anodes and cathodes

New tests focused on a different type of anode and cathode. Original tests were made with simple curved round end of stainless steel rod on which carbon fibre was attached using stainless steel mesh. both materials work as anode and cathode. When meat is decomposing we took into account that content of the bottle should be replaced - for example between exhibitions. It would theoretically also produce more power if content could be mixed during decomposing (future tests). In this regard - carbon cloth has no function. After cleaning with water or otherwise (mechanically) it has no function anymore as it gets destroyed. Also, circulation of heavy particles would damaged carbon cloth. Graphite rods are easy to clean as they are solid.

 proton exchange membrane with agar agar salt bridge



Cathode made from the stripe of carbon fibre 1 m long 5 cm width (photo below is a sample)


The main part of anode/cathode is 40 mm round stainless steel washer connected with stainless steel screw and stainless steel nuts. For the cathode carbon fibre is wrapped around a screw and protected with wrapping of stainless steel wire mesh.


For the anode, holes are drilled through washers. Graphite rods (smooth sandpapered and cleaned with nitro thinner artistic drawing pencils - for tests different softness) are assembled into the whole anode through holes and pressed with a screw)


an example of both electrodes


construction of salt bridge through EVA foam stopper





Old meat blended



 Meat and water blended = 500 g


in 500 ml of water 8 g of probiotic cultures were mixed


100 ml of probiotic cultures is mixed to 500 g of meat + methylene blue (10 drops)






1st of November update:



- all the results are varying. If there would be some conclusion from them is that HB graphite has better electro-conductivity than softer (probably more dirty graphite)