My team is trying to pit tracking wheels against the new V5 inertial sensor. What are your opinions on which one is more accurate, simple, anything. Is the V5 inertial sensor more or less capable than the tracking wheels? Thanks
Inertial sensor is much easier to implement, but tracking wheels are almost always more accurate with good tuning. It’s your decision but I would recommend the tracking wheels if you have the time and programming skill.
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How much more accurate can the tracking wheels get? Is it a significant difference?
IMU and tracking wheels give different Information. IMU will give accurate orientation in 3 axis, but it will not give any position data.
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This is purely anecdotal, but in the past my team has had issues with calibrating the IMU too long before the start of the match, and thereby making it less accurate. The same is not an issue for tracking wheels.
From what I have heard (I do not have an inertial sensor), its heading sensing is fairly accurate, but translational acceleration is still not accurate enough for proper tracking. For translational sensing you’ll still want encoders on wheels.
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I feel so inexperienced asking this, but the V5 motors have those encoders built in right?
You can use the motor encoders, but they will be less accurate than tracking wheels because of the extra friction and possibility of slipping. Tracking wheels are a lot more direct and optimized for position tracking.
Yes, however wheel slippage and slack from chain and gearboxes can cause these encoders to be less than accurate enough for full match odometry.
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Is there a use for the tracking wheels during the match for like advanced teams or is it only utilized in auton?
Sorry if I misunderstood; I was under the impression that this was purely for turning, but if you’re interested in full position tracking you’ll absolutely want to use 3 unpowered tracking wheels.
@5278C Possible; for example in turning point, I believe 5225A used macros which may or may not have been based on their field position. Generally it is only utilized in auton and programming skills.
It’s totally fine. Honestly all this has my head spinning and I’m sightly confused about what our team wants as well
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It depends on the game. For shooting games like Nothing But Net or Turning Point there can be value in being able to at any point on the field automatically turn and target a goal. This year though I imagine it will be less useful during driver control.
Here is a video of a team that I competed with and against in NBN that had position tracking and a turreted flywheel: Team 1826 The Fuse Nothing But Net Worlds 2016 Reveal - YouTube
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Does anybody know when we are getting the new sensors. I’m waiting to CAD odometry wheels for the new sensors.
They unfortunately haven’t given a release date yet. However if I remember correctly, the inertial sensor was released in winter of last year, so it is most probable for the new sensors to be released then.
I think they would have them by at least the first competition since AI doesn’t start in the winter.
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good point, I didn’t think of that
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Physically, the intertial sensor is easier, but on the software side, 3 encoder odometry is much easier, unless you really want to implement what is described here
While position tracking can be useful, the inertial sensor and the built in encoders in the motors work fine. Many people have said that the built in encoders are inaccurate but my team never had a problem with them. We also tried tracking wheels vs just built in encoders and found no real change. If you do want odemetry with tracking wheels then go for it, but you don’t need them to be a good team.
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Could you maybe explain more about that? I always thought the difficulty was the other way around.
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