Add a continuous absolute encoder zeroer
For swerve modules, we need to be able to zero a system where the
absolute encoder has a 1:1 ratio to the output and the output can spin
infinitely. Create an altered version of the AbsoluteEncoder zeroer to
do this.
Tests basically just steal from the absolute encoder tests, with an
extra test to check that it handles multiple revolutions correctly.
Change-Id: I0d2738499480f142bc5703de2c9cf6e345e3a896
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/frc971/constants.h b/frc971/constants.h
index 4f7cb36..cf53287 100644
--- a/frc971/constants.h
+++ b/frc971/constants.h
@@ -70,6 +70,28 @@
struct RelativeEncoderZeroingConstants {};
+struct ContinuousAbsoluteEncoderZeroingConstants {
+ // The number of samples in the moving average filter.
+ size_t average_filter_size;
+ // The distance that the absolute encoder needs to complete a full rotation.
+ // It is presumed that this will always be 2 * pi for any subsystem using this
+ // class, unless you have a continuous system that for some reason doesn't
+ // have a logical period of 1 revolution in radians.
+ double one_revolution_distance;
+ // Measured absolute position of the encoder when at zero.
+ double measured_absolute_position;
+
+ // Threshold for deciding if we are moving. moving_buffer_size samples need to
+ // be within this distance of each other before we use the middle one to zero.
+ double zeroing_threshold;
+ // Buffer size for deciding if we are moving.
+ size_t moving_buffer_size;
+
+ // Value between 0 and 1 indicating what fraction of a revolution
+ // it is acceptable for the offset to move.
+ double allowable_encoder_error;
+};
+
struct AbsoluteEncoderZeroingConstants {
// The number of samples in the moving average filter.
size_t average_filter_size;