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Unread 22-04-2014, 20:36
Gdeaver Gdeaver is offline
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Re: The Perfect swerve

In 2013 looked at high end gaming mice. With swerve and the chassis orientation decoupled, there are 2 solutions of the x and y counts coming from the mouse. On competition carpet and no changes to the optics we found the accuracy to be less than needed. The optic flow algorithm is not tuned for this use. With a usb port on the roborio in 2015, A usb camera highly filtered and a more robust optic flow algorithm may yield better results. A gyro at minimum would need to be fused with the optic flow. This is all for field centric control. There are 2 paths 2 look at. Sensing from the robot reference frame (gyro accelerometer fusion). Adding a world reference frame with a magnetometer or some other sensor to reference out side the robot frame of reference. GPS is out. Constellation navigation has grabbed my curiosity. It's hard. In 2013 we could have reset the gyro every time we went up against the feeder station wall to correct for drift. This year we considered IMU field centric control not doable because of the constant impacts and never having time for a reset. The last thing our drivers need this year is for the field centric control to suddenly shift several degrees while being smash defended and trying to roll out. With our low designs the last several years a magnetometer location and calibration issues ruled out that solution. Fortunately for the future of swerve field centric a couple of companies have released affordable IMUs based on gyro, accelerometer and magnetometer sensors coupled with highly tuned extended state kalman filters that should handle the rough First environment. The key is constant hard and soft iron calibrations on the magnetometer sensor. I'm hoping to make this an off season project if I can get some programming students on board. I think soon a plug and play Field centric IMU solution will be available for FIRST.
 


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