Crazy tracks

walak

Hello!

I try to make a model on tracks (some kind of tank of something). Actually I've done the model, but when it drives through obcastle it's left track start to fly and then lock.

The movie shows what I mean:

http://www.youtube.com/watch?v=Pt_9YOWcYOo

Model:

http://www.filefront.com/15894829/czo%u0142g-better.skp

Any ideas?

Roger

That was entertaining.

Diagnostic path:

Are the tracks components? For example were the two tracks built separately, allowing one to behave differently than the other?
Are the left and right suspension clones of each other.
Are the tracks perfectly in synch (are the links aligned perfectly left and right).
Is the tank on a path perfectly parallel to the slope of the obstacle.
Seems like the track is slipping to one side on its ground wheels. Can you make a mechanism to restrict and left or right motion of the tread?
Did you do this on purpose like an April fools joke?

It kind of fun to watch.

walak

I've made one track first, without joints and then copy it, then added and connected joints.
They can behave diffrent, there is also sliders to control left and right track, but I didn't touch them while running.
Actually, there is no suspension. Wheels in the middle are mounted on hinges. They are clones but have their own joints.
~0,5cm difference. Could it has a matter?
It starts parallel. However, a minimal turning appears after start.
Well, there is something hidden what i forgot to unhide. Every wheel looks like here:

http://i40.tinypic.com/2dudtm9.jpg

Definitely no

Sorry for my english...

Gaieus

I think it is time to move this topic into the SketchyPhysics subforum of the Extensions forum as you will probably find a better support there.

(Sorry Roger, I did not mean to say your are a wrong support of course ).

shareck

you need to add some hidden mass to each link. otherwise if the tracks are passing an obstacle and they're being stretched (because of the weight of the "tank") they will blow apart. i always do this and this trick works quite good but it's still not perfect. you are always limited because of the way the joints in sp behave. they're not very strong and the only way to make a nicely working caterpillar track is by adding hidden mass to the links and reducing the number of links per track as much as possible. check out my nicely working tank (assault gun to be precise): http://www.youtube.com/watch?v=ipY8kgCbA94

Roger

Shareck, shouldn't a tank that heavy deform the soil?