diff --git a/include/ard/rbdl/model/dynamic-robot.hh b/include/ard/rbdl/model/dynamic-robot.hh
index 1b4b603..2151697 100644
--- a/include/ard/rbdl/model/dynamic-robot.hh
+++ b/include/ard/rbdl/model/dynamic-robot.hh
@@ -75,6 +75,13 @@ namespace ard
       /// \brief Get underlying rbdl model.
       virtual rbdlModel_t rbdlModel () const;
 
+      /// \brief Get gravity vector. It is set to a default value on
+      /// initialization.
+      virtual vector3d gravity () const;
+
+      /// \brief Set gravity vector.
+      virtual void gravity (const vector3d& gravity);
+
       /// \brief Get the chain of joints between two joints
       /// \param inStartJoint First joint.
       /// \param inEndJoint Second joint.
diff --git a/include/ard/rbdl/tools/types.hh b/include/ard/rbdl/tools/types.hh
index f702294..a096bb8 100644
--- a/include/ard/rbdl/tools/types.hh
+++ b/include/ard/rbdl/tools/types.hh
@@ -48,7 +48,7 @@ namespace ard
   namespace rbdl
   {
     // Define gravity vector.
-    static const vector3d gravity (0, 0, -9.81);
+    static const vector3d defaultGravity (0, 0, -9.81);
 
     // RBDL typedefs.
     ARD_RBDL_DEFINE_TYPES (RigidBodyDynamics::Joint, rbdlJoint);
diff --git a/src/dynamic-robot.cc b/src/dynamic-robot.cc
index c17af3a..9489e85 100644
--- a/src/dynamic-robot.cc
+++ b/src/dynamic-robot.cc
@@ -113,7 +113,7 @@ namespace ard
       // Initialize rbdl model. This method is called before building
       // the model.
       rbdlModel_.Init ();
-      toRbdlFromMal (rbdlModel_.gravity, gravity);
+      toRbdlFromMal (rbdlModel_.gravity, defaultGravity);
 
       // Build rbdl model.
       if (!buildRbdlModel ())
@@ -150,6 +150,16 @@ namespace ard
       return rbdlModel_;
     }
 
+    vector3d DynamicRobot::gravity () const
+    {
+      return toMalFromRbdl (rbdlModel_.gravity);
+    }
+
+    void DynamicRobot::gravity (const vector3d& gravity)
+    {
+      rbdlModel_.gravity = toRbdlFromMal (gravity);
+    }
+
     std::vector<to_pointer<CjrlJoint>::type >
     DynamicRobot::jointsBetween (const CjrlJoint& startJoint,
 				 const CjrlJoint& endJoint) const