Rotating in Inventor Studio?

[Robofreak]

Hey whats up guys! I am in need of a bit of help but can't seem to find any tutorial that explains what i am trying to do so here is my problem.

 

I am designing a revolver magazine in inventor now its very basic, its a cylinder with 6 holes cut in it using the circle pattern tool. Now each of those 6 holes needs to hole a bullet and as the cylinder rotates the bullet most also rotate to stay in the chamber of the magazine. But here is where it gets tricky!

 

I can rotate the revolver magazine just fine but I cannot find ANY way to rotate the bullets around the center point of the magazine. I tried moving the bullet up on the x and y axis as the magazine rotated which works but it does so in a straight line not a circular arc which in an animation will be very noticeable when the bullets don't move correctly with the magazine.

 

So the real question here is How do I rotate a cylinder in Inventor Studio around the center point of a larger cylinder!

 

 

Any help would be much appreciated

[kencaz]

You will want to add an insert constraint on the bullet to the chamber and an angle constraint on the cylinder to the (grounded) ratchet. Then drive the angle constraint.

 

 

KC

[shift1313]

you can also use the contact solver since Im assuming you will want to "fire" the bullet as well.

[Robofreak]

Hey I made a quick assembly of this because I don't know how you are suppose to apply these constraints.

 

If you guys could apply them to these models and then re attach the file and also post directions on how you did it I would be extremely grateful! I am just so happy that this is even possible because my animation relied on the rotary motion to make everything work right.

 

Here is the link, you have to type in that code to download it first though. It sucks that there is no small attachment hosting on this sight!

 

GO TO filesaver dot COM / assembly sorry i cannot post links yet!

 

 

You guys have been a very big help! Thank you very much!!!

[shift1313]

there are some good tutorials built in to inventor. I believe right on the ribbon bar when you start the program it has a link for tutorials. Also there are a lot that pop up on youtube that walk you through lots.

 

The contact solver i mentioned basically uses the interaction between solid parts. So the bullet would be pushed by the "wheel". Also if you use the Dynamic Simulation you can model a spring loaded gun setup, apply a force to the trigger and "fire" the bullet.

[Robofreak]

there are some good tutorials built in to inventor. I believe right on the ribbon bar when you start the program it has a link for tutorials. Also there are a lot that pop up on youtube that walk you through lots.

 

The contact solver i mentioned basically uses the interaction between solid parts. So the bullet would be pushed by the "wheel". Also if you use the Dynamic Simulation you can model a spring loaded gun setup, apply a force to the trigger and "fire" the bullet.

 

 

Ok now I understand it a bit better and found a youtube tutorial about using the contact solver.

 

Thanks a lot!

 

I am definetly bookmarking this forum its wayyy better than the student autodesk "ask a question" thing which sometimes doesn't get answered and when it does it may take quite a long time.

 

EDIT - I just tested the contact solver on the rotary mag and projectile and it worked perfectly 100%.

[shift1313]

im assuming you found the vid with the two block on youtube? Its really a very nice tool. One thing to keep in mind when driving contraints and using the contact solver/interference check, if your steps are too large it will miss the object. For instance if you were driving an angle constraint for your 6 shooter and you rotated 60degrees with one step, the bullet would more than likely stay in place. If you have 1degree steps it would move it along with the bullet.

 

When trying to set this example up I would draw a plate with a small hole in it. Draw your disc with the 6 chambers and a center hole. using a concentric constraint between this center hole and the one on your plate. Have a coincident constraint between the plate and your disc as well as the plate and your bullet. Then you can rotate your disc around with the bullet in there.

[Robofreak]

I found a video that showed 3 square tubes that fit inside of each other and the last tube had a large base on it. The video showed that if the part was moved it would go through the other larger square tubes but when contact solver was activated the part would move the other parts as well.

 

I haven't had any problems with the bullet not moving with the chamber, it's not an instant movement at the absolute most it would be about half a second for the bullet to rotate.

 

The revolver magazine was going to go into a revolver so that I could make a test animation and make sure that I could get it to work but now I don't think a test is really nessecary.

 

You can see what this is really going to be used for over at 4hv.org, go to the forums section, then "electromagnetic accelerators" and then click on "Concept Coilgun" I am Plasmaarc and all of the models are mine.

[shift1313]

Ill have to check that out later:) I looked at it briefly but its a lot of reading:)

 

I think its a cool project but it sounds overly complex at first glance. You have pneumatic power loading mechanism as well as stepper motors, some sort of water pump system to cool the barrel and so on. If I were to attack a project like this with all these different aspects i would try them one at a time. Since the loading is gravity fed it seems like you could just build the "gun" part of it without a loading mechanism first. There is no mystery to building a coil gun so im assuming the whole point of this project is for the loading mechanism?

 

Is there a reason to this? dont take that the wrong way. Im just wondering. I have a friend that builds this kind of stuff for fun and its cool but he just does it to do it. Im just wondering if you have a reason for a self loading setup. I know you mentioned in your post about doing this as a hobby.

[Robofreak]

Building a coilgun isn't super hard even a triple stage gun is just a lot of time, wiring, and some electronics (scr's, charger ect....). The point behind my gun is the loading system and cooling. It has doesn't have a lot of power at only 2.2kj maybe 3kj (if I can get some more capacitors). Many people have built much more powerful guns that would beat the power of what I want to build hands down. The thing is that no gun has a loading system as complex as mine, it has some many capabilities that conventional loading system lack.

 

I'll start with the watering cooling, if you have ever shot a coilgun repeatedly in a short amount of time you will notice that the coil starts to heat up. With 3kj it will happen very fast and the coils with get very hot after 10 or so shots (if it gets to hot the enamel on the magnet wire will melt off rendering it useless). After it gets this hot you have to wait a while until it cools off through the air. So by adding ice cold water as soon as the heat is generated by the coil the water will absorb the heat much faster and carry it away. You would then be able to fire many more rounds (20 maybe 30) one after the other with a 2 or 3 minute cool down before you do it again. It doesn't have a water chiller built in, I simply went ghetto on that and said it will circulate from a bucket filled with ice and water (this will last a long time). The water pump would not be homemade, its way easier to get a simple electric pump for $20 at homedepot or walmart.

 

You are correct in saying that you don't need my massive loading system to run it, you could manually load a projectile into the barrel and fire which most people do. There are also people that have devised bolt action systems and spring fed magazine systems although I always found them to look sort of fragile.

 

The system that I came up with allows the gun to fire very rapidly ( as fast as the pistons and stepper motor can move (as well as if the gun is charged!)). On top of that its fully computer controlled there is no need to have any manual interaction with the gun other than loading it to begin with. The other really cool thing is that you can pick which ammo you want to fire. So lets say you put 3 types of ammo in the gun (2 x heavy hitting low velocity) (2 x mid range/power) ( 2 x high velocity rounds) with this system you could immediately change which ammo the gun is going to fire. That way you could shoot a tin can as close range with the heavy rounds to demolish it and then snipe a soda can from very long range with the high velocity rounds. Don't get me tempted, I was seriously thinking about adding ammo storage boxes with a small robot arm to suck up the projectiles and place them in the loading dock . That way it would have up to 100 rounds of on board ammo!

 

 

I am doing this project for a few reasons.

 

1.To practice inventor for an upcoming competition (I have learned so much already doing this)

 

2.I enjoy solving problems and engineering stuff this is my fun

 

3.Its a challenge that know one has done yet

 

4.If it is actually built then it may help me get into college.

 

I am only a sophomore in high school so funding for these projects is hard to come by but even if I can only build a scale model of this gun it will still be very rewarding to me.

 

You can see some of my other projects that I did on my youtube page.

 

Can't post links yet but anyway

 

go to youtube dot com /halo2maniaccc

 

Don't ask about the name, I picked it years ago and now I can't change it!

[shift1313]

Glad to see there is some thought behind it! One thing you want to be really careful of is narrowing your focus. For instance with the water cooler. You may have some interesting problems. Thermal transfer at the temps you are talking(melting the enamel is several hundred degrees above boiling water). To simplify the setup you may use extruded heat sinks around the coils with thermal transfer tape(i use this stuff for heatsinks from chips to aluminum bodies) and a fan. I dont know if inventor 2010 has any thermal flow stuff built in(havent gotten that far with it) but if your setups is right there may be no cool down period. These heat sinks could also have water passages in that would allow you to pump water through if needed based on a thermistor on the barrel.

 

The most robust designs are the most simple ones. To really help yourself out make sure you entertain a few possibilities. This will show a university that you were able to come up with feasible designs and weigh the best one.

 

A design project I did one semester involved making a very large design matrix, coming up with questions, answer the questions and putting everything together to weigh the options.

 

Here is a sample QGD chart.(note just one i found on google).

 

http://gpd.engin.umich.edu/dfm_projects/blender/blender_qfd.jpg

 

This type of analysis will show that you put thought into the design and chose options that were the best and not just the coolest or easiest etc. Only reason i bring this up is because ive built a few things that I was stubborn on and pushed my initial idea through. It needs to evolve:)