Let's Make Robots!

Bipedal Chair Progress - NOT FINISHED YET!

Bipedal Human Transport


Well, video is up.  I dont show anyone sitting on it because I'm the only person who knows how to controll it and I had to shoot the video, so I just let it walk solo. Enjoy :]

BTW at the end one of the neighbors is like "whats that?"  so I, (almost startled) say "um...robot" and the video ends...



June 5, 2009 Update:

Well I never could get a video...yet.  I'm doing some repairs and upgrades today, and rebuilding the control box.  WITH ANY LUCK it'll stop raining here and I can shoot a video on our new, flat, and level driveway ( hehe :] ).  I must say however that I am disapointed at how ugly it truly is...especially compaired to this: http://basicrobotics.net/mech.html

WOW I need that thing... I'm seeing an expensive new project coming in the next few months.....

But I'm not done yet.  These actuators are AMAZING.  I'm going to figure out how to build a more efficient, better looking frame with whatever money I can save up.  Then just transfer the actuators, and bam, WIN.


OK the brand new batteries already died.  I put a 10 amp car fuse to regulate the amps, too.  I have an 18 volt drill battery on it (6 volts more than supposed to) and it still walks frustratingly slow.  You can't even tell its walking on video.  But on the good side, I made an brilliantly designed way of controlling it without anything more than tape, wires, tin foil, glue, and a box.

Here it is (It has 1 big switch for back and forth motion, two for independent side control to recalibrate, and one master cut-off switch):  I know its hard to make it out, its very complex and immaturely built, plus lighting is bad.





It walks!  I am sooooooo happy!  My actuators came today, and I've been pondering forever on how to get it all together safely...  And it all paid off.  Test 1 was a 50% sucess, because the wheels gave in to the twisting motion of the legs.  Tests 2 and 3 were 90% sucess, because it walks, but it walks backwards (although technically I never even defined a front or back yet, seemg how its a square...)

It held my weight, and walked flawlessly.  I will post a video tomarrow!  Thanks for sticking with me!




Ok, sooo close.  I have the money.  I finished the frame.  Now I just need the actuator.  I found a pair of cheap, 250 lbs actuators, 85 lbs stronger than the last one I chose.  In less than two weeks I'll have it done and walking...


I also updated specs.  Instead of a rechargable battery, I chose alkaline.  It's cheaper, as my budget is shrinking.  The new actuators are 250 lbs now, not 165.  There are also no sensors like I had planned.  And my idea to put 10 amp fuses on it probably won't happen, because the actuators only can go up to 5 amps.  So that's it, stay tuned for more...!




 That's my dog Abby on the latest frame.



The new actuator model, capable of 250 lbs.





Side View



Front View



Extended View



This is the first side of my "Mech"

 It's hard to make out the shape chair yet because I only have 1/4 the parts so far... this project will be completed probably early May, but I'll update in the meantime.


This chair dubbed TP (or TS) is a walking chair, as in you sit i it and it walks (bipedal).  Here's the CAD model of the final design:



Neat, huh?



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I envision a new "Human Interface Device" to control the human's weight shifting by the micro controller. Two sharp pins rising from the seat. One under each buttock. With each step the sharp pain or (with learning actuators like these), the anticipation thereof will set the body weight in motion. Just get the timing right.

What kind of actuator mechanism do you plan to use for the tilting ancles?

nope, no tilt anymore.         

after some thought i fugured a robot this big would have a good chance of breaking if it tilted, because my first attempt (which i never posted) failed totally, and i wanted to be sure that this one works just right


it has wheels on the feet so that they can glide over serfaces more easily as if the foot was off the ground.

i'l be finishing it next month, so I'll post a video within a few weeks at most.



That thing looks awesome! I hope it works.

thanks!  i'll post a video of my latest progress ASAP!

toy robots with the same kind of "walk" usually has wheels that can only roll forward. This make sure that one leg remains stationary while the other pushes forward. With free running wheels, one foot will roll backwards while the other rolls forward, then they'll both run back to their starting position before repeating again in opposite order for the other step.

The solution used in the toys I've disected are variations of this:


The cogwheel is mounted on the same axle as the wheels underneat the foot. When the cogwheel rotates counter clockwise, the red arm just slides on top og the "teeth". But when you try to turn the cogwheel clockwise the red arm will get stuck against the first cog/tooth it encounters.


The technical term for that is ratchet. But you may be describing the function of a freewheel.

Yes, I've seen that.  in fact, my earliest bipeds used that.  This new robot uses a similar technique.  a metal bar like below with rubber or something slides along the ground.  Then when it backs up, it sticks into the ground, allowing the other leg to move forward.  I couldn'y make the "rachet" (that rik said it was called) strong enough for 200 lbs.



I tried to 'Keep It Super Simple"  but I think this is pretty good.  It is an outdoor targeted robot.  And my tests have shown that this would work on coarse surfaces like carpet, cemet, asphalt, etc.


FOR ALL THAT IS HOLY IN THE WORLD, USE A FUSE!!! I can truly say from vast personal experience fuses have saved my ass many, many times. On that note -I lost a good motorcycle because of a paperclip (which replaced a fuse)! This is simply the best $3 insurance one can ever buy.