LEGO - Tank climber test

[oracid]

Until now, I have shown what was working. But, as you can imagine, I did other tests that did not work.

I think it is interesting to know what does not work. This saves time, unless we want to study the reasons for these failures.

The balloons for sculpture:

It is these balloons with which one can do all kinds of animals in folding.

This seems a great idea. The balloons are thin, they can be cut into slices or braiding on track. But unfortunately, they are very slippery. Too bad, it was very nice.

The inner tube of a bicycle wheel:

This was my first failure. I was very disappointed. The idea was to cut thin strips of more than one meter in one tube and move them into the holes of the tracks. Unfortunately, if through the plait, the car rides well stairs, he cannot climb the slope because the material is too slippery.

Hot glue:

The idea was to place hot glue on the sculptures of the elements track. It works fine, but it become very slippery very quickly.

The "silent blocks" for door :

It is these little buttons that are stuck on the door frame to avoid the noise. This does not work at all, very slippery.

Silicone collapsible tube:

Too slippery.

[oracid]

This time it is not about track, but about suspension.

The idea was to make a suspension that keeps the horizontal symmetry of the tank.

Usually the tanks are oriented, there is a "front" and a "back", and the suspension is oriented to favor the advance, which could cause problems when the tank goes back.

My suspension is not new, but I think, it has never been used on a tank.

This is a vertical suspension. For a small robotic tank, I think it will not be a problem.

But I know that here there are specialists and would like to know their opinion on this subject.

Thanks in advance.

Edited February 19, 2016 by oracid

[Tommy Styrvoky]

I think a christie style or torsion bar suspension with sway bars would perform better than the current design, because those are both designed for high speed tracked vehicles. The current suspension design you are using exerts force vertically, but it applies a lot of horizontal force to the axles, thus causing lots of friction. The sway bars for the torsion bars and christie style suspension will eliminate the horizontal force and friction being applied to the current design, though there are some minor issues, it will be easier for the suspension to function going forwards, because of the direction of the sway bars. Though the Germans designed a interesting means of allowing it to function well in both directions, by having one side of sway bars facing backwards on the left side and the right side facing forwards.

The T-18, and T-28 use a similar system for the suspension mentioned in your video, it uses wheels in pairs on bogies though.

Christie suspension

Torsion bar

If you're looking for a suspension type that works well in both directions look at VVSS or HVSS

VVSS (vertical volute spring suspension)

HVSS( Horizontal volute spring suspension)

Edited February 19, 2016 by Tommy Styrvoky

[oracid]

Tommy, thank you very much for that answer so complete and well documented.

Of course, I expected such a response, it is for this reason that in my video, I am very skeptical.

I did not know that the Soviets have used this type of suspension, although significantly improved.

I understand your reservations about the horizontal forces acting on the axles, but still, do not you think that this is an acceptable compromise on this scale?

Or, finally, do you think I should abandon this solution?

I think back to all this more closely watching your videos and your documentation.

Thanks again.

[Joefraser]

Abandon nothing!

Test everything, and film it :).

[oracid]

Abandon nothing!

Test everything, and film it :).

Don't worry.

Be sure that I always keep my free will and my critical mind.

[oracid]

This series of small videos is ended.

The last video, I present it in a new thread for those who are not interested by the "making off»: http://www.eurobricks.com/forum/index.php?showtopic=122127

But do not worry, I come back soon with a new series, with highest stairs and a bigger tank.

Thank you for your attention.

[oracid]

I have changed my mind, I have decided to continue testing in this thread.

How to put two tracks together ?

In this video I show how to put together two tracks with a D joint.

This is necessary for a bigger tank.

Edited February 24, 2016 by oracid

[oracid]

Medium Tank Climber Test #9

To climb stair steps which are 10cm high, it is necessary that the length of the tank is larger.

In this video I show a medium tank that has the following dimensions and characteristics:

55cm length

41cm width

13cm height

weight 2kg,

4 engines XL

double width tracks

In real life, stair steps are nearly 17cm height, the adventure is not over...

[MacKaiwer]

I like that new double track solution very much And I like you and your videos and your presentation, you are like some mad scientist and that is freakin' awesome Love you man!

[oracid]

I like that new double track solution very much

It is not only a double track solution. You can assemble 2, 3, 4 tracks, as much as you want.

you are like some mad scientist and that is freakin' awesome Love you man!

I'm not sure to be a scientist, but my wife says too I'm mad... it must be true then ! I love you too.

[oracid]

Big Tank

Weight: 7.5 kg

Length: 81 cm

Width: 51 cm

Height: 12cm

As you know, I show you what works, but also what does not.

To climb stairs of real life, with steps of 17cm in height, I need a big tank. Unfortunately, it is too heavy.

However, the assembly of 3 tracks with D joint may interest some of you, as well as the drive wheel (2903c01) and the guide pins (32002).

This solution is not good, but already I am thinking about another one. I do not give up, be sure of that.

Here my YouTube channel :

Edited March 14, 2016 by oracid

[oracid]

Lego – 17cm Stair Tank Climber #10

My goal was to climb stairs of real life whose steps have a height of 17cm.

To reach this goal, I thought it had to be a very large tank (81cm) and so very heavy 7.5kg. This was a failure.

So I changed my mind by making a tank, the smallest and lightest as possible.

A final issue exists, it is the nosing that I cannot cross. But it is true that there are all kinds of stairs, each with specific constraints, and want to solve all issues is to risk not to take the first step.

I started by 5cm steps and 10cm and today I crossed steps 17cm.

I think I have reached my goal.

Length: 67 cm

Width: 42 cm

Height: 12 cm

Weight: 1,560kg

4 XL motors

[oracid]

In this video, I propose a solution for crossing the nose of the first step of a stair.

My solution consisting of 4 small fixed arm, which does not increase the complexity of control, unlike the mobile arms.

The other advantage of this solution is that it does not require an increase in the height of the tank which would have required an heavy rigidification of the structure.

[BusterHaus]

Good solution to the lip on the steps. I think you may be reaching the limits of the motors - they seem to be getting close to stalling when climbing the first step. A speed reduction would help if you are planning to add any more weight.

Are you going to make the chassis more rigid?

[oracid]

I do not think the problem comes from the motors but from the battery.

No, I will not do more rigid chassis. The goal was to climb real stairs and it reaches.

With this new knowledges, I will make a new project, and there, I promise you, the structure will be more rigid ...... if necessary.

[BusterHaus]

I don't see the chassis flex as a bad thing in a model of this size. Attempting to make it very rigid would add too much weight and it performs very well with the flex. I would compare it to wood vs steel frame rollercoasters - the wood ones are designed to have a bit of give and not be 100 percent rigid.

What are you planning to build next?

[oracid]

What are you planning to build next?

I think my new project will also be a tank. Maybe not much bigger, but with 8 XL motors and an EV3.

If it does not exceed 3kg, then I would like to fit it with an articulated arm. Something like a deminer. Of course, I will talk about it here, but probably in a new thread.

Edited April 10, 2016 by oracid

[MacKaiwer]

Very impressive machine that tank at #11 Now just waiting your new project, you are the man, keep up the good work!