How to change angle of shooter?

[dchartley]

Here is a vid of our first test run on the chassis. Frisbee shooter works fine and the elevation adjustment runs off of a jack screw powered by a window motor. Used a couple of basic door hinges so that the angle of the motor and screw can change freely.

Doug

http://youtu.be/fuEmQBhBpnw

[BurkeHalderman]

We're using a single air cylinder mounted on the side of the shooter to switch between being level (loading angle) or shooting angle, probably around 35 degrees. To fine tune the shooting angle we're using a magnet on the cylinder to adjust the stoke length.

A fairly simple solution

[Bstep]

Originally Posted by BurkeHalderman

We're using a single air cylinder mounted on the side of the shooter to switch between being level (loading angle) or shooting angle, probably around 35 degrees. To fine tune the shooting angle we're using a magnet on the cylinder to adjust the stoke length.

A fairly simple solution

Could someone please explain how a magnet can be used to adjust the stroke length of a pneumatic piston?
Thanks

[G Fawkes]

Originally Posted by dchartley

Here is a vid of our first test run on the chassis. Frisbee shooter works fine and the elevation adjustment runs off of a jack screw powered by a window motor. Used a couple of basic door hinges so that the angle of the motor and screw can change freely.
Doug
http://youtu.be/fuEmQBhBpnw

How did you connect the lead screw to the window motor?

[BurkeHalderman]

I believe there are different kinds of switches that can be used to adjust the stroke of an air cylinder. The method that I was referring to uses a sensor that can be adjusted along the body of the air cylinder.

This works because the sensor detects a magnet on the inside of the cylinder, once the rod has extended to the desired position the sensor will send a signal which will limit the stroke to that postion.

More information can be found here :

http://www.bimba.com/products-and-ca...?searchRef=yes

[JohnFogarty]

I know for a fact our team is mounting the front end of our shooter on a bar as the pivot point and then the back end will be sitting on a CAM. Which will allow us to change our angle.

[waialua359]

Originally Posted by kingbrandon14

We are planning to use an igus lead screw (picture above) attached to a strong motor to move the front end of the shooter up and down. We are still debating whether we should have two of these mechanisms (one on each side), or just one.

Another idea is to use pneumatics, but the disadvantage of that is there are only 2 positions: all the way up, and all the way down.

We have a lead screw being used to adjust our shooter mechanism, which for the most part, is working like a charm. I cant believe the 1st banebot gearbox ratio we chose was the best one.
Initially after the shooter was built, we mounted it to a varying angle extruded aluminum frame to match the height where we designed the shooter to be. From there we determined the optimal angle range of the shooter head. Thus, the decision to design a varying angle shooter using the lead screw was determined.

[2348humanplayer]

I'd suggest a cam. Basically an offset disc to transform rotational to linear motion. It's compact, and works smoothly.

[jasp]

you could use a screw attached to an encoder to change angle. I would only use pneumatic if you are using pneumatics for something else on your robot because they are very heavy.

[dchartley]

Originally Posted by G Fawkes

How did you connect the lead screw to the window motor?

We took the black plastic splined connector that came with the motor and glued in the jack screw using JB weld. Took some attention to keep the joint symetrical. The window motor seems to be geared just right for this application.

Doug

[G Fawkes]

Originally Posted by dchartley

We took the black plastic splined connector that came with the motor and glued in the jack screw using JB weld. Took some attention to keep the joint symetrical. The window motor seems to be geared just right for this application.

Doug

Thanks for the quick reply.

How do you keep the black connector on the window motor?

[capnslow]

Last year we did something very similar with a window motor. We used a screw through the plastic connector and into the window motor shaft. However, you have to be careful because last year we had continual problem with pulling the metal cover off of the window motor because it's only crimped on and we were pulling with the screw.

[dchartley]

Originally Posted by G Fawkes

Thanks for the quick reply.

How do you keep the black connector on the window motor?

We use the force of gravity. The shooting platform weighs enough to hold it down. We had thought about using a bungee but that wasn't necessary.

Doug

[jp1247]

Originally Posted by kingbrandon14

Another idea is to use pneumatics, but the disadvantage of that is there are only 2 positions: all the way up, and all the way down.

Not entirely true. I spent last weekend testing the plausibility of pneumatic angling. By using a dual solenoid, and 1 spike controlling it, im able to get infinite variation with no lack of strength.

The solenoids two red leads go to M+ and M- of the spike, the black going into a splice on the ground side of the spike. By setting the the spike to full forward (12 volts on both pins, 0 pot. difference) the cylinder hold position due to equal pressures. I can then simply set the spike to forward or reverse to raise and lower the piston, having it default back to holding. On a 1"" bore bimba piston, i cant move the shaft at all. Flow control valves on the piston allow me to control how fast it moves up and down.

I may link a video if i get the chance on sunday...

[Negative 9]

Originally Posted by ksafin

Well we ended up using a car jack that we motorized with a BAG Motor & VersaPlanetary box.. works pretty well; video here:
http://www.youtube.com/watch?v=GrscT...ature=youtu.be

What did you use to get the motor onto the end of the screw of the car jack?