inspirations  >  Ken Gracey  >  biped robot gallery 23 May 2021
(26 October 2008)

Ken Gracey's biped robots Toddler
# Mini Toddler
# Parallax Toddler
# Penguin
# Penguin-2
# Parallax Pengiun
# Ken's Bipeds

The story of Biped walkers following on from BigFoot would not be complete without covering the amazing amount of development effort put in by Ken Gracey of Parallax Inc - where the Stamp computer was invented.

Ken first contacted me on 18th September 2000 after obtaining samples of BigFoot from Milford Instruments who distribute Parallax products in the UK.

He was kind enough to ask if he could use my two servo design for a three foot high biped he was planning to build.

On 29th September Ken wrote again with details of his Toddler, shown right.

It is a pleasure to introduce to you our heavy metal version of your small Big Foot, the "Toddler". I built Toddler in our metal shop using a mill, lathe, punch, bender and break in about a week. He is very well made, and is a close scale to your small Big Foot. He is constructed from .063 aluminum, Delrin, threaded rods, 1/4 scale servos, diamond plate aluminum, standoffs, screws, and blue LEDs. Toddler walks forward, backwards, turns left and right with no problem. I've used three IRODS modules to detect the front and two sides as it wanders around. You'll see from the video how he clanks and sounds like a monster. It was very popular at the Embedded Systems Conference this week in Santa Clara.
On the 3rd February 2001 Ken wrote again and I have quoted it because it shows what a nice company Parallax is.
I have attached a picture of the Toddler. He is walking really well these days - which brings up a point. I am interested in producing an all metal (precise) production version of the Toddler, more like the size of Big Foot. I'd use some of the same design concepts used in the larger version I made.

Key to the entire approach is the two-servo idea I got from you. I entirely respect your design and don't want to proceed without your blessing. Often when ideas like yours are created they are suddently duplicated and used throughout the world. And, depending on the culture and company, some will never even aknowledge that the idea wasn't origional as they march forward with their designs.

Mini Toddler
By the 20th May 2001 Ken wrote that he was on the third version of the Toddler and on the 7th June wote with its success at a Dallas Personal Robotics Group meeting.
My Toddler (well, your concept) won three awards at the recent Dallas Personal Robotics Group meeting. It beat the wheeled bots on the line-crossing contest, won best engineering and got a third award (a friend submitted the bot and I don't remember the final one). Anyhow, we think the design has merit as a higher-speed walker by putting the legs in more of a parallel-o-gram which involves less heel-toe walking.
In BigFoot the legs were as near a parallelogram as I could make them because I didn't think heeling and toeing would lead to stable walking. Later Ken said he experimented with many different Toddler foot linkages. And as it turned out, the parallel solution worked the best by far because it allowed for larger steps. Basically, the Toddler could take a big step forward without landing on the heel at a steep incline. With a trapezoidal arrangement the heel-toe pressure was quite high and caused him to lunge forward!

Parallax Toddler
By February 2002 Ken had ordered prototype parts from a machine shop and they expected Toddler to be released on 15th May 2002.
Ken sent me a couple of Toddlers which I received on the 7th June. It was so exciting putting them together, I hadn't built somebody elses robot kit since I reviewed Hebot-II in 1982. Assembling a kit was a lot easier than designing and making one.

Parallax's Toddler page at 25th November 2002

Toddler videos

By May 2005 Ken had completed two Penguins.
- BASIC Stamp 2px microcontroller
- (2) micro servo motors
- Hitachi HM55B digital compass for navigation
- Infrared emitters and detectors for object detection
- Socket for a Parallax "Ping" ultrasonic sensor for up to 3m objectdetection - Two photoresistors
- Blue mini 7-segment LED for identification in groups
- Speaker in body

And wrote

Also, I am adding a ZigBee wireless programming interface so they can communicate with each other and the PC in groups. Will be very interesting. These walk really well nearly perfect. They can run faster than a Toddler with their precisely-milled parts. Its been a lot of fun, for sure. Not certain they will ever become a product due to high manufacturing costs.
But once the bug has got you it is almost as if the robots have a life of their own and like real children keep calling out for more and in September 2005 he had just finished anodising the latest batch of parts and sent me a picture before adding the electronics:-

- Lynx 433 Mhz wireless receiver for PC control
- HM55B digital compass
- blue seven segment LED
- photoresistors and infrared sensors
- speaker
- BS2px module (40 milliamps power draw)

And in December 2005, Penguin and Ken's other bipeds were featured on the cover of Servo magazine.

Parallax Penguin
Despite what Ken kept saying the Penguins did make it into production.
They are absolute works of art.
Real art, not the phoney kind of the 'art world'.
Production Penguins

Parallax's Penguin pages
September 2007

Ken's Bipeds

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