|
|
|
![]() |
|
|||||||
|
||||||||
| View Poll Results: How do you choose values for tank drive? | |||
| Mathematically (Please define below) |
|
5 | 29.41% |
| Path based |
|
3 | 17.65% |
| Experimentation |
|
8 | 47.06% |
| Other |
|
3 | 17.65% |
| Multiple Choice Poll. Voters: 17. You may not vote on this poll | |||
![]() |
| Thread Tools | Rate Thread | Display Modes |
|
#16
|
|||
|
|||
|
Re: Tank Steering
Quote:
P.S. - I'm also impressed at the amount of truly useful information that has appeared in this thread in just a couple of hours, as compared to some of the other ones that go on for days and weeks, and provide nothing of value (<cough> game hints </cough>) ![]() |
|
#17
|
|||||
|
|||||
|
Re: Tank Steering
Quote:
How would turning off a gyro ever help, though? Integrated angular position from a gyro drifts over time, and power cycling will reset this drift, but then the gyro is "starting" at an unknown orientation. |
|
#18
|
||||
|
||||
|
Re: Tank Steering
Quote:
We will only need to keep track of true heading if we take it another step further and do autonomous travel. But there are many hurdles to get over first, like not crashing when tilting forward to go in a straight line ... . We'll probably put a compass on board at some point too, but as a 3rd heading sensor.I also wanted to note that it doesn't really make sense to power cycle gyros in FRC unless your robot is trying to spin in place for several rotations and stop at an exact angle. The quadrotor only does it because with environmental effects (e.g. turbulence) on such a lightweight system, the thing winds up spinning 720 degrees over a 10 minute period sometimes. Last edited by JesseK : 02-09-2009 at 13:23. |
|
#19
|
||||
|
||||
|
Re: Tank Steering
Quote:
In 2007, we were one of the most consistent teams in the country scoring the tubes on the rack-n-roll rack. We were consistent to about 1/4 inch true position through the use of a gyro, two encoders, and knowing the center of turning of the robot. We were skid steer. In 2008, we consistently did 4 lines unless we were blocked by another bot, and we knew exactly where the robot was going to turn and end up. Using skid steer, a gyro, and two encoders. In 2009, we had the robot set up to accept an angle and a distance from two dials on the board so we could put it anywhere we needed it (barring collisions of course). We didn't account for side skid just for simplicity's sake. We used a gyro and two encoders. Skid steer is extremely easy to navigate with by doing constant angle / distance calulcations at a decent rate and averaging them between the sides. In fact, functionally, the math is no different that the trig you do with the swerve. On what do you base the idea that not many people with skids have done much with navigation? Last edited by Tom Line : 02-09-2009 at 13:38. |
|
#20
|
|||||
|
|||||
|
Re: Tank Steering
All I'm going to say on the 6WD skid navigation is:
1024's 2008 automode. (I can also name several other teams, including my own, but choose not to.) |
|
#21
|
|||||
|
|||||
|
Re: Tank Steering
Quote:
I stand by my statement, encoders (on drive wheels) and gyro alone are sufficient for accurate navigation even at high speeds. As Chris said, separate dummy wheels would be superior, but teams did just fine with out them in 08. |
|
#22
|
|||
|
|||
|
Re: Tank Steering
Quote:
I don't recall the equation, but you can spend some time on the wikipedia page or the internet in general and get a parametric equation for the cubic spline. Quote:
left = 1.0 + turn right = 1.0 - turn Like always, the hard part is tweaking the constants. |
|
#23
|
|||
|
Re: Tank Steering
Quote:
Also on carpet, there isnt as much skidding, so it is not as important then? Quote:
Quote:
|
|
#24
|
|||
|
|||
|
Re: Tank Steering
Quote:
If you are trying to point the robot in a direction in order to go in that direction, the error is some measurement that is fairly linear and will be 0 when you are pointed in the correct direction. The heading error was what I used when trying to go to a way point. |
|
#25
|
||
|
Re: Tank Steering
Quote:
Quote:
|
|
#26
|
|||
|
|||
|
Re: Tank Steering
Quote:
You don't have to worry about what it does between the points. Just apply forwards power, and PID your heading. The robot can't make sharp turns easily, so it'll take a bit to make the turn and that will smooth the turn out. You can also just up the number of points. This is the same thing as approximating a circle as a many sided polygon. The more sides, the better the approximation. |
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| need glp programing steering with a steering wheel | Matchew | Programming | 2 | 10-02-2003 14:20 |
| Under or Over? To tank or Not to tank that tis the question! | archiver | 2001 | 2 | 23-06-2002 22:53 |
| Single Joystick Tank Steering | archiver | 2001 | 5 | 23-06-2002 22:49 |
| tank or go-cart style steering? | archiver | 2001 | 17 | 23-06-2002 22:42 |
| tank steering | archiver | 2000 | 10 | 23-06-2002 22:28 |