We are happy to announce the birth of our latest creation, Aluminalis, a sixteen-legged walking creature.
Along with her sixteen legs and feet, Aluminalis has a fast and lively brain (an Arduino Nano), strong muscles (gear motors), elegant bones (custom aluminum linkages), two multi-segmented spines (custom crankshafts), ears (Xbee Radio), forward and rear sight (ultrasonic sensors), and a voice (tone buzzer). If you communicate with her in the right way, she will respond to your requests, but she prefers operating on her own, and in some moods, she can be very shy.
Aluminalis is pronounced Ah-lumin-alis. Her full scientific species name is actually Animaris Aluminalis. We derived the name from the word aluminum. As far as we know, she is the only species of the Animaris genus that evolved entirely out of machined aluminum components. Be sure to watch the video, which Camille and I put together. Read below for a species description, evolution, and behavior. At the end of this post, we discuss the original inspiration for Aluminalis.
Aluminalis is about 6″ tall and 22″ wide. She consists of a central thorax and two multi-legged sides. Each side is driven by a motor, which drives a pinion gear, which drives a main gear, which drives a four-section crankshaft, which drives a complex set of linkages, which drives the legs. The four crankshaft sections on each side are 90-degrees out of phase with each other so that at least one pair is always firmly on the ground. This is accomplished because the crankshaft is square rather than round. As the motor rotates the crankshaft, the legs loop through a tear-dropped-shaped stepping motion similar to a horse’s gait, causing Aluminalis to walk similar to other animals. Aluminalis changes direction by putting more or less power to the motor on each side. To go forward, she puts equal power to each motor. To go left, she gives the right motor more power than the left motor. And so on. Aluminalis can also go backwards and pivot in place.
We sketched the original concept for Aluminalis on paper and then designed the various components in SolidWorks. Aluminalis consists of 846 individual components. We machined the segment bars, crankshaft components, thorax plates, and most of the other aluminum components on our CNC mill, vertical mill, table saw, band saw, and drill press. We also used an extensive amount of 1/8” aluminum bar, 1/8” set collars, #4-40 set screws, #6-32 set screws, washers, and ball bearings. There are two long 1/8” steel rods on each side that hold the segments together.
The gears that are visible on each end of Aluminalis and several other components were provided by our fantastic sponsor Actobotics.
The electronics include many components from our friends at Sparkfun, including the Xbee radio, the Explorer Regulated Board, two Maxbotix ultrasonic sensors, the tone buzzer, wires, resistors, LEDs, and other components.
The 20mm 73:1 gear motors, the motor mounts, and main power switch are from our friends at Pololu.
Aluminalis uses an Arduino Nano as the main microcontroller, a 12V 3-cell Lithium-Polymer Battery, and a Sabertooth 2 x 5 amp motor controller.
Aluminalis operates on command (i.e. remote control using the Xbee radio) or on her own. She is still learning and developing, but so far, she has two autonomous modes: The first is roaming. She roams around the workshop using her ultrasonic sensors to find the optimum path and avoid obstacles. The second mode is what we call “shy mode,” which is quite fun. In this mode, she uses her ultrasonic sensors in coordination with her motors to run to the center of the room. If you then move toward her, she will automatically move away from you, centering herself between you and the rest of the room, constantly adjusting her position as you do. The only difficulty with this mode is that once you let her off the leash she’s very difficult to catch!
The Inspiration and Naming of Aluminalis
Aluminalis was inspired by the renown Dutch artist Theo Jansen and his wonderful Strandbeest creatures, which are large kinetic sculptures that he builds out of PVC plastic pipes on beaches in the Netherlands. His awesome sculptures are actually wind driven, rather than motor driven, which makes them even more impressive. Theo always refers to his creations as living animals, for in his heart and mind they are new forms of life. In honor of Theo’s amazing work, we have adopted Theo’s view on this issue, and we’ve also adopted his naming convention, which is to give each species of artificial animal a scientific name with the genus Animaris. So, the full name of our creature is Animaris Aluminalis. As far as we know, Animaris Aluminalis is the only aluminum strandbeest alive today, although we expect them to multiply over time like all living creatures. We would also like to thank Jason Allemann for posting his excellent Youtube video of his Leggo steampunk walking ship, which was also a big inspiration for us.
Species Range & Habitat
Anamaris Aluminalis is exceedingly rare and highly elusive. This species is believed to favor mountainous regions in Western North Carolina. In particular, it likes living underneath workshop cabinets and usually comes out at night. It feeds on nuts, screws, and small robots.