davidbuckley.net
home  >  Shadow Leg v2 < Ullr > Teal 20 September 2021

Ullr - by David Buckley September 2019

Ullr is a four servo 9 inch (225mm) high biped walking robot, controlled by a PicAxe40x2.
Ullr is driven by four servos and powered by four AA cells.
Ullr can walk Forwads, Backwards, turn Right and Left, step Sideways and Kick.
Ullr can lie down and Crawl Forwads, Backwards, and turn Right and Left, then stand up again.
Ullr can get up from any position if it falls over.
The wings on the head are to assist in getting up from upside down.
The Black Box holds 4AA cells.
On the face and in the feet there are forward facing high power orange LEDs for illuminating obstacles which then can be detected by the black shrouded phototransitors next to them.
There are downward facing IR sensors on each foot for detecting table edges and black areas.
There are two tip sensors so Ullr can tell if it is tipped forwards or backwards.
Long range sensing can be done by the Ultrasonic ranger module.
Being Aesir, Ullr has Blue LED 'eyes' which are dim when waiting for a command and bright when executing one.
The 'eye' state can can also be set by the user as a HMI.
Ullr can play sounds and Ring-tunes from its onboard speaker.
Ullr can store sixteen user inputted 16 character command strings in its memory.
There is a socket for extra memory so hundreds of commands could be stored.
Ullr can be instructed by commands from a Sony IR remote-control.
The full set of instructions can be sent serially as text over cable or a plugin radio module.
Ullr has an on-board command-help file.

Ullr is the latest in my Aesir series of four servo biped robots controlled by a PicAxe40x2, and each of them - Loki, Freya, Thor, Baldur and now Ullr has a different geometry.

The Aesir
Loki is very stable, can get up if it falls over when doing crazy moves and is a stealthy walker.
Freya amazed me, it has no trouble getting up even from lying upside down and is the best at coping with pens, pencils and other items lying on a table.
I like the way Thor stands up from sitting, and when sitting or crouching is very stable but when standing tall is easily upset and can't get up if it falls over.
Baldur is surprisingly stable and can get up from any position and can crawl and do a Roly Poly forward or backward.
Ullr is also very stable and can crawl and get up from any position and can walk sideways with ease.

Ullr Software

Ullr Servos
Servos - Cirrus-CS601-BB-STD 5.5Kgcm@4.8v, 0.2sec, +ve clockwise,
jerk on poweron if not already being pulsed.