THE LONG WALK!!

**daliad100** · 2nd July 2009, 19:05

Hello everyone, 'tis my first post.

I may be wrong, but I'm not sure that using an exceptionally clever linkage like a Klann or Jansen (http://www.mechanicalspider.com/comparison.html)to convert continous rotary motion of a motor to movement of a step counts as a walker.

I have always thought a true walker to have to use the drive motor to reverse the legs direction i.e. using pneumatics, hydraulics, linear actuators or servo motors being moved backwards and forewards in a specific order to make the robot walk.

To me, a linkage is an overcomplicated shuffler. However, as yours is only a promotional bot then you have no need to worry about whether you will be allowed the extra weight allowance (unless you want to fight with it.)

If you're interested in wanting to build a true walking robot then I have a two designs, one hexapod and another quadrapod on Incredibots (http://incredibots.com/). Unfortunately, their servers are down at the moment so I can't post the bot. However, when they do come back online i'll post them and you all can have a look.

On a final note, I suggest using Incredibots in modelling linkages etc. as it's very good at that (I'm pretty sure I saw a spider using either a Klann or Jansen linkage on there.)

Just my 2p (more like 10) on walking robots.

**daliad100** · 2nd July 2009, 20:34

The Incredibots servers are back up now so I can give you a link to my walking machines.
Quadrapod: http://incredibots.com/?robotID=dali...31c04.54213413
Hexapod: http://incredibots.com/?robotID=dali...b3a39.03183432

Both only need four motors to move and they would both use the same walk cycle programme (see instructions in game.) If you look at one side of the walk cycle for the hexapod (red or blue legs) then you can sort of see how it would turn using normal tank steering. Invertability is relatively simple with the hexapod, just extend the legs out the top.

The Quadrapod one is only one side of it and two of those would be needed for tank steering. I believe it to be a more solid machine with more grip, however, it would be far more difficult to make it invertible without complicated shafts that go through one another (at the moment I would be placing motors on top of the leg.)

I hope you enjoy my long, ever so slightly mad ramblings about walking robots.

JB

**craig_colliass** · 3rd July 2009, 13:25

Hi Jordan welcome to the forum

I just went to the rules on building a fighting robot, and for walkers there are only two entries.

The first about Weight limits

2.2
Legged robots (walkers) can weigh up to twice the specified weight in all classes. A walker must employ moveable legs to support its weight. Robots with rolling or sliding mechanisms will not be classified as walkers.

And the second about drive definitions

3.1.1.
Rolling (wheels or the whole robot)
3.1.2.
Walking (linear actuated legs)
3.1.3.
Shuffling (rotational cam operated legs)

As you can see any robot that is held up on its legs, and moves as a result of their linear motion (that is not rotational eg camshaft, or in other words it is not a wheel with legs sticking out of it) is a walker by these rules. :shock:

None of this matters because as you say my robot won't be used for combat but I would love to see a feather walker it would be good fun for the crowed to watch but I donâ‚¬â„¢t see it as being competitive. even if it did weigh 27.2kg!!
Still thatâ‚¬â„¢s never stopped me before!!

**craig_colliass** · 4th July 2009, 10:40

As promised some photos

http://s569.photobucket.com/albums/ss13 ... GA5007.jpg
http://s569.photobucket.com/albums/ss13 ... GA5005.jpg
http://s569.photobucket.com/albums/ss13 ... GA5004.jpg
http://s569.photobucket.com/albums/ss13 ... GA5006.jpg
http://s569.photobucket.com/albums/ss13 ... GA5003.jpg

The legs are cut from 6mm thick aluminium plate the links between the bell crank parts will be doubled up to help strengthen the legs. the long links go to the crank.
The next jos is to make up the Oilon bearings and washers for the link joints!

**craig_colliass** · 8th July 2009, 21:44

Made 36 thrust washers from 3.2mm nylon only 134 more to go

Started fixing the transmision shaft bearings to the first pod, I have decided to go for a reduction gearbox with the motor, and a two stage reduction chain drive, with a friction torque limiter, this should give a reduction ratio of around 100:1. Final drive 17mm silver steel shaft for the cranks to be fitted on.

**muchalucha** · 9th July 2009, 19:36

this looks fantastic

**joey_picus** · 10th July 2009, 12:25

Looks very good Craig, I can see it looking quite impressive when all the legs are going at once

**daliad100** · 10th July 2009, 12:27

Just an idea for shoes, two blocks of wood (in the shape of the shoe) on either side of the leg bolted together through the metal. Glue some strips of rubber on the bottom of them for grip or just cut the ends of the wooden blocks to be textured. What you do with the bottom of the feet really depends on what the robot will be walking on. Really smooth (like a wooden floor), use the rubber. Reasonably rough (like a playground), go for wood.

Looking really good.