diff --git a/frc971/constants.h b/frc971/constants.h
index 7f1f1d5..6188f01 100644
--- a/frc971/constants.h
+++ b/frc971/constants.h
@@ -68,6 +68,8 @@
   double allowable_encoder_error;
 };
 
+struct RelativeEncoderZeroingConstants {};
+
 struct AbsoluteEncoderZeroingConstants {
   // The number of samples in the moving average filter.
   size_t average_filter_size;