diff --git a/Project.toml b/Project.toml
index a6805a7..54b9745 100644
--- a/Project.toml
+++ b/Project.toml
@@ -25,6 +25,7 @@ BenchmarkTools = "0.5"
 ForwardDiff = "0.10"
 Parameters = "0.12"
 RobotDynamics = "0.3.1 - 0.3.1"
+Rotations = "1"
 StaticArrays = "1.0"
 TrajectoryOptimization = "0.4.1 - 0.4.1"
 julia = "1"