Shooter Aiming Methods

[DjScribbles]

My opinion is that controlling the angle vertically will be more important than rotational angle control. We have wide targets, but they aren't tall.

[Anupam Goli]

Originally Posted by DjScribbles

My opinion is that controlling the angle vertically will be more important than rotational angle control. We have wide targets, but they aren't tall.

Using the speed of the shooter and a table of experimented speeds vs distance can also overcome the short goal height.

[Ether]

Check out this post. It's not directly related to shooter aiming, but it does have some useful qualitative observations about shooter wheel speed and slipping:

http://www.chiefdelphi.com/forums/sh...2&postcount=55

[stingray27]

For vision processing, I believe I am going to setup a system that uses vision processing, but at a minimal level. Last year, we wrote some code to attempt and follow the targets at all times. This didn't seem to fit to the game and so this year we are going to revise that method. The labview code for vision targeting from last year is a really good reference for those of you trying to figure it out. The only change you have to make is when determining the aspect ratio subscore, you have to compare it to the targets aspect ratio this year instead of the aspect ratio from last year (18 by 24). I am just going to divide the width and the height and then later use that number to determine what target the camera is currently looking at. I can then throw out the aspect ratio subscore when determining if the camera is looking at a target or not and use the other 3 subscores as the determining factor (convex hull operation score, or the rectangle coverage %, and the vetical and horizontal line scores).

As for actually using the vision information, I believe that we may go with just a single button that activates a vertical alignment of the shooter. Since the target is so wide and just limited in height, the shooter then would line up vertically and then hand over control to the operator. The horizontal alignment would just be from the driver. This allows for just a quick rough alignment of the robot and then the operator would only have to perform quick slight fine tuning.

Any thoughts?

[ctccromer]

Here's my PLANS for this year (final results may vary):

1) Auto-aiming system with a shooting system that does NOT move on a turret or anything. It can aim up/down slightly, but that's the only axis it moves on and only to an extent

2) I'm switching to a controller this year and my very first idea for coding the robot was to not only make the joysticks turn and move the robot, but also code it so that while I have the left trigger held down, make the joysticks turn and move the robot at 0.25 normal speed. This way you don't have to JUUUUUST BARELY NUDGE the turning joystick a bunch of times to line up the shot -- you can manually aim the whole ROBOT (not the shooter on a turret) at the goal, then use an algorithm to aim the shooter's motor speed and vertical height, NOT horizontal angle

[fb39ca4]

Last year, we had a slow mode button on our controller as well.

[falconmaster]

We had a great deal of success last year by locating landmarks on the field and then lining up with them and then launching the balls. We think we can do the same this year. To assist us though we are going to use a "photon cannon" aka flashlight http://www.amazon.com/8066-T6-Rechar...ts+1000+lumens
Like the three days robot builders guys. From our experience this is much faster and more reliable than computer vision processing. There are too many variables to account for that a human can adapt to that a computer without an extensive vision processing program can do as well or fast. Just my two cents...

[Anupam Goli]

Originally Posted by falconmaster

... There are too many variables to account for that a human can adapt to that a computer without an extensive vision processing program can do as well or fast.

This. Playing 20 minutes of Catalyst made me realize that within one hour of practice, a driver could find a sweet spot, sweet angle, and fire consistently. Granted, a very extensive vision processing system could do the same, but if your driver is confident enough, it'll most likely be faster for a human to line up to that sweet spot that is ingrained into the driver's mind.

[Dan Richardson]

Originally Posted by Wing

This. Playing 20 minutes of Catalyst made me realize that within one hour of practice, a driver could find a sweet spot, sweet angle, and fire consistently. Granted, a very extensive vision processing system could do the same, but if your driver is confident enough, it'll most likely be faster for a human to line up to that sweet spot that is ingrained into the driver's mind.

I think this is a great observation that is often overlooked. Having a good drive team is the keystone to a competitive robot. Great drivers need practice. Even good drivers get better with time at the sticks. Most teams seem not to make practice time a priority. Put this priority at top of the list and rethink resource strategies and your bot will instantly be more competitive.

Back on topic, I believe the photon cannon to be one of the most elegant targeting methods to date. I only wish we'd thought of it first.

[KrazyCarl92]

Using the pyramid as an alignment device and protection from interference by the opposing alliance seems like a great aiming method. Just back into the 30" horizontal bar and have the robot square up and you are in a known, consistent position relative to the target. And with the targets being so wide, the one degree of freedom this alignment method affords (translation short-ways across the field) also happens to be the largest dimension for the target. If a robot can score reliably from this position as well as one other defense will be rather difficult and aiming is REALLY easy from one of those positions.

[stingray27]

For anyone wanting a explanation of what the example code for vision processing is doing, I put up a youtube video here: https://www.youtube.com/watch?v=m2Pwdq30eSI last year where I explained to my mentor what it was doing. Please bear with it as it is toned down, slow and probably all not incorrect (and long). But I have gotten some good feedback in that my explanation made a lot of sense to even non-programmers. Check it out if your interested.

[jesusrambo]

Our plan for this year is to have extensive auto-targeting to align the turret on the fly as we move, but with only movable elevation. Azimuth will be handled by actual driving, though we're planning on having that automatically align too. The image processing will be offloaded to the driver station, though we're looking into using an onboard computer.