Go to Post ...your stress reliever is a ziptie with the end cut off so you can pull it straight through. It really works! - Storcky [more]
Home
Go Back   Chief Delphi > Technical > Technical Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #5   Spotlight this post!  
Unread 07-02-2015, 03:03
TheOtherGuy's Avatar
TheOtherGuy TheOtherGuy is offline
Unregistered User
AKA: Kevin Forbes
FRC #4183 (Bit Buckets)
Team Role: Engineer
 
Join Date: Jul 2006
Rookie Year: 2006
Location: Tucson, AZ
Posts: 408
TheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond reputeTheOtherGuy has a reputation beyond repute
Re: Severe Issues with Andymark Swerve and Steer Module

Quote:
Originally Posted by Elfonzo View Post
I find it necessary to alert all teams who have already purchased the Andymark Swerve and Steer Module of issues in its performance. Andymark is offering a better, "absolute zero," (as we like to call them,) sensor. This "better" sensor always has a point it can refer to as zero, eliminating the need for pre match centering/zeroing. However, because the gear that the sensor is attached to and reading from is 12 tooth, and the gear used for turning the assembly is 40 tooth, the sensor has effectively 3&1/3 "zero's" This causes HUGE problems when trying to read the position. If you have not completed your electronics board and given the programmer(s) a chance to test it, be prepared to come up with major issues.
You will definitely have a problem trying to get the current angle of the module when you first turn on the robot (3-1/3 rotations/module rotation = 10 zero-ing angles), which is why you'll need to make sure the wheels are aligned before grabbing the initial position of the encoders.

You can get the current position by keeping a running sum of the encoder ticks, making sure to add the right change when it wraps around a zero point. Get the position by calculating the modulus of the total encoder ticks in a full module rotation (resolution * 3-1/3) and the current value. If you run over (or under), be sure to wrap around past the other extreme.

Quote:
Originally Posted by JesseK View Post
There's a local team who started swerve on Day 0 for the first time ever. They got it up and running with programming by the end of Week 3. They're using AM's product, but haven't reported a problem zero-ing it out since they're good about pre-aligning the wheels to each other at the start. They're using CAN via the Talon SRX, and it works incredibly well.
I wonder if they're using the hall effect encoder? http://www.andymark.com/product-p/am-2816a.htm
Which would make this much more trivial*, given the position is accumulated on the SRX and one simply needs the total encoder ticks per revolution of the module.

*Well, not trivial...
__________________
 


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 00:43.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi