Forum: General Forum
11-07-2016, 11:00 PM
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Replies: 14
Views: 2,155
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Forum: General Forum
10-31-2016, 11:48 PM
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Replies: 17
Views: 1,309
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Forum: C/C++
10-29-2016, 06:54 PM
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Replies: 4
Views: 232
Re: Syntax for 'virtual void GetDescription'?
virtual void GetDescription (std::ostringstream &desc) const =0
Piece by piece:
virtual
This means that the function is virtual. Derived classes can provide a function with the same signature...
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Forum: Programming
10-29-2016, 06:04 PM
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Replies: 6
Views: 783
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Forum: Programming
10-27-2016, 12:00 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
Probably not. Stereo was totally unnecessary for estimating range to the goal last year; we were able to estimate our distance to within a few inches using only the method described in the previous...
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Forum: Programming
10-26-2016, 11:58 PM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
Yep. I'll point you to a few places in the code that help explain how.
First, in the Android app, we find the pixel coordinates corresponding to the center of the...
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Forum: Extra Discussion
10-23-2016, 03:32 AM
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Replies: 98
Views: 10,557
Re: paper: Stop the Stop Build
Where did I make this argument? I do not think this, and did not say this.
Of course every team has a schedule, and has presumably put considerable thought into it...thought that all assumes a...
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Forum: Extra Discussion
10-22-2016, 02:05 PM
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Replies: 98
Views: 10,557
Re: paper: Stop the Stop Build
Wouldn't extending build season to include several more weekends be to your benefit? I won't pretend to know how your team operates, but I can tell you about our experience last season. Virtually...
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Forum: Programming
10-22-2016, 01:05 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
Great question! I assume you are referring to (my) definition of path vs. trajectory from the motion profiling talk (these definitions are hardly universal).
Path: An ordered list of states...
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Forum: General Forum
10-21-2016, 11:29 AM
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Replies: 69
Views: 6,365
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Forum: General Forum
10-21-2016, 11:25 AM
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Replies: 69
Views: 6,365
Re: [FRC Blog] Stop Build Day Survey Results
Agreed. This would be a relatively non-controversial change; one that simply gives the advantage that district teams already enjoy (especially those who attend extra events) to everybody.
Even if...
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Forum: Programming
10-21-2016, 11:12 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
If we had infinite time, I'm sure we would have. Instead, we used a combination of SmartDashboard / our own web interface (https://github.com/Team254/FRC-2016-Public/tree/master/installation/logger)...
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Forum: Programming
10-20-2016, 03:42 PM
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Replies: 30
Views: 5,787
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Forum: Programming
10-20-2016, 03:26 PM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
Yeah - the logic for staying straight is here (https://github.com/Team254/FRC-2016-Public/blob/master/src/com/team254/frc2016/subsystems/Drive.java#L385). There's a PID controller that compares our...
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Forum: Programming
10-20-2016, 11:10 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
1) we went slowly enough that worst case slip was limited.
2) we used closed-loop velocity control on the wheels to ensure that even if one side of the drive train momentarily lost traction, we...
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Forum: Programming
10-20-2016, 12:14 AM
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Replies: 57
Views: 5,847
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Forum: Programming
10-20-2016, 12:12 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
I'm not sure what you're referring to? We did have a "traction control" mode that used closed-loop speed feedback along with a gyro to cross defenses while remaining straight, but this didn't...
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Forum: Programming
10-10-2016, 02:27 PM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
It's pretty informal. We all worked on our various pieces and commit to head/email patches as we go (occasionally there's a long-running branch, but we try to avoid that). Typically in the lab or...
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Forum: Programming
10-10-2016, 01:40 AM
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Replies: 30
Views: 5,787
Re: Team 254 Presents: FRC 2016 Code
3 reasons:
1) We found that of the various methods available for grabbing and decoding an image out of the camera buffer, this was the fastest.
2) It let us minimize memory allocation and buffer...
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Forum: Electrical
10-04-2016, 10:32 PM
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Replies: 23
Views: 2,057
Re: NAVX vs. Spartan board
Both of them have been used successfully by many teams, and you can't go wrong using either for helping determine your robot's heading.
Honestly it is really hard to judge a gyro by its spec sheet -...
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Forum: Programming
10-04-2016, 03:02 PM
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Replies: 57
Views: 5,847
Re: Tuning PID Constants Over a Range
Talon SRX closed loop control implements PIDF. The "F" stands for feedforward - and this works in all of the available closed-loop control modes (current, velocity, position, profile).
However, the...
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Forum: Programming
10-02-2016, 07:39 PM
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Replies: 57
Views: 5,847
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Forum: Programming
09-29-2016, 03:26 PM
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Replies: 57
Views: 5,847
Re: Tuning PID Constants Over a Range
Yep, and this is the equation we actually used as our starting point (using the track width and wheelbase length of our inner four wheels). Our CoG was within an inch or two of the geometric center...
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Forum: Programming
09-29-2016, 11:51 AM
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Replies: 57
Views: 5,847
Re: Tuning PID Constants Over a Range
Yeah, use one controller with gyro angle as the process variable to track a desired heading profile. The output of this loop is a desired angular velocity. You can then use an inverse kinematics...
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Forum: Programming
09-28-2016, 02:32 PM
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Replies: 57
Views: 5,847
Re: Tuning PID Constants Over a Range
I agree that a motion profile + feedforward to overcome static friction can solve this problem adequately for FRC purposes. However, the Talon SRX makes precise 1KHz velocity control stupidly easy...
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With any dollar amount to invest I would be more interested in the number of individuals (students is too narrow) impacted than the number of teams created--after all, this is about people. - kramarczyk [more] 
