diff --git a/src/IMU_tools.h b/src/IMU_tools.h
index 4f6ecda67b6695723b11ddecc56403da57a931a0..6d231223554ec4ea5e196cb7220a40e0eb42c001 100644
--- a/src/IMU_tools.h
+++ b/src/IMU_tools.h
@@ -34,10 +34,10 @@
  *   - between: Db = D2 (-) D1, so that D2 = D1 (+) Db
  *   - composeOverState: x2 = x1 (+) D
  *   - betweenStates: D = x2 (-) x1, so that x2 = x1 (+) D
- *   - lift: got from Delta manifold to tangent space (equivalent to log() in rotations)
- *   - retract: go from tangent space to delta manifold (equivalent to exp() in rotations)
- *   - plus: D2 = D1 (+) retract(d)
- *   - diff: d = lift( D2 (-) D1 )
+ *   - log: got from Delta manifold to tangent space (equivalent to log() in rotations)
+ *   - exp_IMU: go from tangent space to delta manifold (equivalent to exp() in rotations)
+ *   - plus: D2 = D1 (+) exp_IMU(d)
+ *   - diff: d = log_IMU( D2 (-) D1 )
  *   - body2delta: construct a delta from body magnitudes of linAcc and angVel
  */
 
@@ -345,7 +345,7 @@ inline Matrix<typename D1::Scalar, 10, 1> betweenStates(const MatrixBase<D1>& x1
 }
 
 template<typename Derived>
-Matrix<typename Derived::Scalar, 9, 1> lift(const MatrixBase<Derived>& delta_in)
+Matrix<typename Derived::Scalar, 9, 1> log_IMU(const MatrixBase<Derived>& delta_in)
 {
     MatrixSizeCheck<10, 1>::check(delta_in);
 
@@ -366,7 +366,7 @@ Matrix<typename Derived::Scalar, 9, 1> lift(const MatrixBase<Derived>& delta_in)
 }
 
 template<typename Derived>
-Matrix<typename Derived::Scalar, 10, 1> retract(const MatrixBase<Derived>& d_in)
+Matrix<typename Derived::Scalar, 10, 1> exp_IMU(const MatrixBase<Derived>& d_in)
 {
     MatrixSizeCheck<9, 1>::check(d_in);
 
diff --git a/src/test/gtest_IMU_tools.cpp b/src/test/gtest_IMU_tools.cpp
index 14957c9791a4754c254319b90f1d93c4e7763225..9f0f8c398e1f7b51690228f5ff3f75be4e66b01d 100644
--- a/src/test/gtest_IMU_tools.cpp
+++ b/src/test/gtest_IMU_tools.cpp
@@ -129,7 +129,7 @@ TEST(IMU_tools, lift_retract)
     VectorXs d_min(9); d_min << 0, 1, 2, .3, .4, .5, 6, 7, 8; // use angles in the ball theta < pi
 
     // transform to delta
-    VectorXs delta = retract(d_min);
+    VectorXs delta = exp_IMU(d_min);
 
     // expected delta
     Vector3s dp = d_min.head(3);
@@ -139,11 +139,11 @@ TEST(IMU_tools, lift_retract)
     ASSERT_MATRIX_APPROX(delta, delta_true, 1e-10);
 
     // transform to a new tangent -- should be the original tangent
-    VectorXs d_from_delta = lift(delta);
+    VectorXs d_from_delta = log_IMU(delta);
     ASSERT_MATRIX_APPROX(d_from_delta, d_min, 1e-10);
 
     // transform to a new delta -- should be the previous delta
-    VectorXs delta_from_d = retract(d_from_delta);
+    VectorXs delta_from_d = exp_IMU(d_from_delta);
     ASSERT_MATRIX_APPROX(delta_from_d, delta, 1e-10);
 }