Sunday, January 2, 2011

Week TechVideo, 2010 #52 - Biped Saurus Robot

Menno Gorter just made an improved version of his NeXTosaurus Walker Biped Robot [1, 2, 3]. Now called Nxt2saurus.
Despite the very similar look with its old brother, it uses a completely new design, according to the author. It seems also quite faster and more agile!

NeXTosaurus is scanning its surroundings with the ultrasonic sensor and is able to search its way out of labyrints.
The robot uses weightshifting technique to balance itself and can turn on his own footprint using only two NXT motors.
Quite "simple" and effective, walking through obstacles!



Making use of just two servos it reveals a very ingenious mind, to find the minimum required steps, for an effective and balanced walk.
As usual, Menno makes a nice video and shoot some photos without revealing much of his secrets.
Just because of that, it would deserve a TechREVERSE challenge on its own!...

Looking at the new Saurus improved performance, I just wish it would become a model to included with the presumably next MINDSTORMS kit (NXT 3.0), or a very similar version of it...
Don't you agree?



Edit:
Menno added some information trough this post's comments, that I found relevant to add to post text itself.
So here it goes...


"In the beginning there was my RCX-Nordic.
A nice RCX-biped with two motors capable of turning in it's own footprint.
It worked really fine, but a short while after this model I became a MDP-member so I made the NeXTosaurus version.

Observing that NeXTosaurus I discovered that is was able to avoid a lot of obstacles without the use of its sensors!
Quite handy since the ultrasonic-sensor wasn't able to detect all of the obstacles.
The idea of my PF-Raptor [4, 5] was born.
( You have to watch that video on my you-tube account to understand what it means when I say that it's possible to avoid obstacles without the use of any electronics. ( I made 3 of these kind of robots; See also Geared-Ant.))

After Legoworld 2010 I combined all the experiences and insights to make Nxt2saurus.
Because this model can walk and avoid obstacles perfect, with only the motors turning, it is very easy to program.
I solved a lot of the problems of NeXTosaurus in a mechanical way.
Observe the movements of its tail for example. That part stabilizes the biped a lot.
When watching the videos you will discover Nxt2saurus became about ten times faster, even on very soft undergrounds!

Thanks for the attention, Menno."




Last Update: 2011.Jan.07 02:30 CET

14 comments:

Parax said...

NXT alt model, yes I agree! Its a great walker seems to cope perfectly. very well implemented to work on just two motors, I would love to see the mechanism up close!

Jetro said...

There are a couplr of pics of the first version in Menno's BS gallery:http://www.brickshelf.com/cgi-bin/gallery.cgi?f=181379
But they don't reveal a lot...

Menno Gorter said...

My attempt, to add some extra information here, seems to be rejected....

Jetro said...
This comment has been removed by the author.
Jetro said...

@Menno Gorter - if you are having trouble posting information you can contact me at:
lego.ambassador AT technicbricks DOT com

Conchas said...

@Menno Gorter

I didn't figure out what you may have attempted, but if you need some help, let us know (e.g. if you like to have some information added into the post).

Menno Gorter said...

O.k. lets try again:
This time a shorter version...

In the beginning there was my RCX-Nordic.
A nice RCX-biped with two motors capable of turning in it's own footprint.
It worked really fine, but a short while after this model I became a MDP-member so I made the NeXTosaurus version.

Observing that NeXTosaurus I discovered that is was able to avoid a lot of obstacles without the use of it's sensors!
Quit handy since the ultrasonic-sensor wasn't able to detect all of the obstacles.
The idea of my PF-Raptor was born.
( You have to watch that video on my you-tube account to understand what it means when I say that it's possible to avoid obstacles without the use of any electronics. ( I made 3 of these kind of robots; see also Geared-Ant.))

After Legoworld 2010 I combined all the experiences and insights to make Nxt2saurus.
Because this model can walk and avoid obstacles perfect, with only the motors turning, it is very easy to program.
I solved a lot of the problems of NeXTosaurus in a mechanical way.
Observe the movements of it's tale for example; that part stabilizes the biped a lot.
When watching the video's you will discover Nxt2saurus became about ten times faster, even on very soft undergrounds!

Thanks for the attention, Menno.

P.s.; At this moment I'm not involved in any official Lego-Program.
So it will be unlikely that one of my models will be a set or kit.

Conchas said...

@Menno Gorter

So you managed to do it! :)
Yes, I don't know the number of characters, but it seems the blogger comments are limited in their size.

I indeed have observed how the Nxt2saurus tail movement, helps to balance the whole walker.

Great that you raised our attention to explain how your PF walkers can mechanically avoid obstacles.

You suggest that Nxt2saurus uses this capability to avoid obstacles. However it also has one ultra-sonic sensor.
Does it means it uses a combination of both methods to complement and improve obstacle avoidance performance?

I'm thinking to add your explanation to the original post!


Also wondering, how one gets out of the MDP program, while it seems you still pretend to be in.
Is there a periodic revaluation based on criteria that you must fulfill to get your participation renewal?
Think this is not the case, at least for the MCP program!?


Br, Fernando

Jetro said...

Thanks for the extra insight Menno!

MDP was the model development and testing stage for the NXT product just before it was launched. The program was then closed.

MCP is kind of continuatoin of MDP, but with a different objective.

You can learn more about this in the article I wrote about the history of the MCP in Hispabrick Magazine 009.

Menno Gorter said...

You're right Conchas;

The NXT is programmed to detect and avoid obstacles using the Ultrasonic-sensor in the head and a touch-sensor in the neck.
( Both head and arms are connected to a touch sensor while they are also moving towards the direction.
Wasn't easy to get that working. )
In case the sensors fail the biped will avoid the obstacle in a mechanical way.

I've added an second touch-sensor to the mechanism.
So it isn't necessary to put the motors in a specific position before starting and the sequence adjust itself automatically.

And I didn't use any universal joints!
Because the grey-ones are not strong enough for this job and I didn't want to use red-ones because they don't match with the orange NXT-parts in my opinion.

Menno.

( I was to late to sign in for the MCP because I was abroad; bad luck?
Last year I got a mail they still didn't need me, so my conclusion is that I'm not good enough. :-)
It's not my problem; I'm never bored..... )

Conchas said...

Now it becomes clear what the touch sensor is doing there. :)
I've seen just one of them in the video, so it seems you're still making improvements.

I also realized that it doesn't use u-joints. Have an idea how you may have achieved it, but that's it, one idea! I'll not try to reverse your work. :D

Keep the good work!

Menno Gorter said...

Nxt2saurus isn't chanced lately; you might have seen there are three cables connected to the sensor inputs?
The other touch-sensor is a RCX-type and is hidden under the NXT. ;-)
Maybe in time I'll add an extra sensor;
I'm thinking about a G-force/tilt sensor.
When the underground is steep Next2saurus actually can fall !
So when it is able to detect even that....

At this moment I'm working on several projects.
One prototype is already shown here ( NXT-Omnispider ), some are held secret and I'm refreshing some older models like the NXT-Grub...

Conchas said...

Very well hidden that touch sensor! :D
Did not check the number of sensor cables.

Mike Sprigg said...

Finally i have figured it out...
Awesome work Menno Gorter, you inspired me..

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