LEGO Tank Warfare

[Kelkschiz]

Hey guys, this is my latest MOC.

Been working on this MOC for a long time. Apart from it's appearance the biggest difference with its predecessor is the integration of an EV3 in the turret. That took quite a bit of work because the EV3 unit and the Mindstorms motors are so much bigger than the PF ones. Had a hard time building a turret that was roughly the same size as the previous one. The main reason for wanting to include the EV3 was because I wanted the gun barrel to be self-stabilizing, that is keeping its elevation regardless of the elevation of the hull. Its implementation can be improved upon. While it does its job adequately, the mechanism should operate faster. At the moment it works like this: take measurement → compare measurement with previous measurement → adjust the barrel accordingly → take new measurement, etc. This cycle can take upto 10 seconds to complete, depending on the difference in elevation, which is too long really. But this time around the main objective was to get it working in the first place. It was my first attempt at making a program for the EV3, which was more difficult than I had expected. I have some ideas on how to improve it, but that will have to wait for a bit.

Now I've made videos about LEGO tanks before. However this one is a little different because I also set out to include something of a story in this video. It's also my first video where I had multiple people collaborating with me on different parts. That is besides my best friend, Depipro, who has helped me before. Hope you will like it.

Edited April 23, 2016 by Kelkschiz

[Alasdair Ryan]

I really like the functionality of it,but the width of it is too wide.

Do you have a picture of V1?

[oracid]

Great tank and great vidéo !

[Tommy Styrvoky]

Would it be possible with the EV3 to create a program for if a change is detected with the gyroscope, then it adds/subtracts the detected difference to the current position of the motor. Is there a way to set a max/min degrees for the motor, so it would prevent it from overrunning it ? Then have a statement that would disable the gyroscope when user input is applied, and re-enable it when it is finished.

[Kelkschiz]

I really like the functionality of it,but the width of it is too wide.

Do you have a picture of V1?

You do realize that you just called my little baby too fat, don't you!!!

Haha, just kidding . V1, what is that?

Great tank and great vidéo !

Thanks!

Would it be possible with the EV3 to create a program for if a change is detected with the gyroscope, then it adds/subtracts the detected difference to the current position of the motor. Is there a way to set a max/min degrees for the motor, so it would prevent it from overrunning it ? Then have a statement that would disable the gyroscope when user input is applied, and re-enable it when it is finished.

Actually your first sentence is a pretty good description of the program I made. I don't think it would be too difficult to make it so that the barrel never overextends. That would actually be a natural extension of the current program. At the moment things get messed up when the barrel overextends. In that case the program doesn't "know" the position of the barrel anymore.

Where is the gyroscope sensor in your example? It's attached to the gun barrel right? That's the only way I can make sense of what you are saying. In my situation it is attached to the turret. I did it like that to enable the user to manually elevate the gun barrel without the program getting messed up. The barrel will just elevate and for the program nothing is changed. When the tank moves and the inclination of the turret changes then the gyro sensor will notice and will try to compensate so that the barrel is restored to the inclination it was set to.

Fixing the gyro sensor to the gun barrel would have a lot of advantages. But then it would become very difficult to deal with manual changes in elevation of the gun barrel. I have not been able to find a way to remotely change the elevation of the gun barrel and at the same time figuring out a way to tell the program that it is a user input instead of a change in inclination of the terrain. That is why I chose to attach it to the turret instead. I think Ideally you would want a system with two gyro sensors, with one attached to the turret and the other to the gun. But Unfortunately I don't have two sensors.

Edited April 24, 2016 by Kelkschiz

[Tommy Styrvoky]

Where is the gyroscope sensor in your example? It's attached to the gun barrel right? That's the only way I can make sense of what you are saying. In my situation it is attached to the turret. I did it like that to enable the user to manually elevate the gun barrel without the program getting messed up. The barrel will just elevate and for the program nothing is changed. When the tank moves and the inclination of the turret changes then the gyro sensor will notice and will try to compensate so that the barrel is restored to the inclination it was set to.

Fixing the gyro sensor to the gun barrel would have a lot of advantages. But then it would become very difficult to deal with manual changes in elevation of the gun barrel. I have not been able to find a way to remotely change the elevation of the gun barrel and at the same time figuring out a way to tell the program that it is a user input instead of a change in inclination of the terrain. That is why I chose to attach it to the turret instead. I think Ideally you would want a system with two gyro sensors, with one attached to the turret and the other to the gun. But Unfortunately I don't have two sensors.

I was thinking attach the gyro to the turret, another solution is to have two seperate carriages, the gun is attached to the carriage, and is elevated by a pf motor, then the main carriage is just mimicking the motion of the gyro mounted in the turret. Here's a image of a concept I worked with, by using a battery box to mimic motion with a servo. I think ideally a 3rd party solution would be better in this case, such as an arduino with a gyroscope and a couple pins going to a motor.

lego vertical stabilizer concept by Tommy Styrvoky, on Flickr

Edited April 24, 2016 by Tommy Styrvoky

[Alasdair Ryan]

What I meant was is this tank built based on previous versions of a design (mark1,mark 2 etc....),if so can I see your first version (mark1)?

Edited April 24, 2016 by Alasdair Ryan

[Kelkschiz]

What I meant was is this tank built based on previous versions of a design (mark1,mark 2 etc....),if so can I see your first version (mark1)?

Ah I see :)! Actually the Mark 1 and 2 were nothing special... and that is being very kind. You could also say that they were ugly as hell :P. I started making pictures when I got to the Mark 3, which I was pretty happy with... at the time. But looking back at it (https://www.flickr.com/photos/33425520@N07/albums/72157645136481323), lets say the Marks have come a long way.

[Alasdair Ryan]

It is interesting to compare as this is how real tanks are developed,your mark 3 tank is too wide too.

Some improvements I would consider for the next version are better armour covering the tracks and sides,thinner width of the tank and faster gun movement.

Edited April 24, 2016 by Alasdair Ryan

[Kelkschiz]

It is interesting to compare as this is how real tanks are developed,your mark 3 tank is too wide too.

Some improvements I would consider for the next version are better armour covering the tracks and sides,thinner width of the tank and faster gun movement.

Why do you think my tanks are too wide?

I have already build the chassis for my next tank and it will indeed have fully covered tracks.

[Alasdair Ryan]

It just looks (in my opinion) too stumpy two wide and too short.

Edited April 24, 2016 by Alasdair Ryan

[Kelkschiz]

It just looks (in my opinion) too stumpy two wide and too short.

I see what you mean. The width I use is due to my focus on function. With my builds I follow the "form follows function approach". I always try to make the diameter of the turret ring as small as possible, and that diameter + the width of the tracks = the width of the tank. The diameter of this tank had to be slightly wider than the previous tank to accommodate the significantly larger EV3 servos. After that I could still have decided to make the tank longer to give it a sleeker look. However the length of the tracks is a crucial factor in the road-handling characteristics. The longer the tracks, the more friction the tank has to overcome when traversing. Considering that one of my main goals is that it actually needs to perform well, even on rough terrain. Add to that the fact that LEGO builders are severely limited in the available engine power that LEGO offers, I felt I had to compromise where the length is concerned. It may be that at some point in the future that will change. For instance when I learn to build even more compactly, lighter and/or I get access to more powerful motors. I just wanted to make clear that it is not as simple as deciding how wide the tank will be.

Edited April 25, 2016 by Kelkschiz

[dr_spock]

I think your tank width is fine for open country combat.

[Kelkschiz]

I think your tank width is fine for open country combat.

Thanks :)

[Kelkschiz]

Hey guys, Just want to let you know that I made a simple video about the technical side of my Mark 7 LEGO Tank. I also mention several Eurobricks members in it who helped me in some fashion. Also if I didn't mention you by name doesn't mean you didn't help me, because there are just so many people here that manage to inspire me. For instance oracid and Alasdair Ryan, I didn't mention you in the video but you for sure had some impact on what I chose to talk about.

Also for those who haven't seen my LEGO Tank Warfare video, I made a shorter one that focuses on the second half of the video where all the action is.

[oracid]

For instance oracid ... for sure had some impact on what I chose to talk about.

I am very flattered...

I have duly noted what you say about the tank size.

[Alasdair Ryan]

Nice video,I can see why the haul is so wide.fitting all those mechanisms in a tight space is not easy.