diff --git a/src/rrrobot_ws/src/rrrobot/include/arm_representation.h b/src/rrrobot_ws/src/rrrobot/include/arm_representation.h
index 56ac021..6dc4a37 100644
--- a/src/rrrobot_ws/src/rrrobot/include/arm_representation.h
+++ b/src/rrrobot_ws/src/rrrobot/include/arm_representation.h
@@ -41,7 +41,7 @@ class ArmRepresentation
 public:
     ArmRepresentation(const KDL::Frame &base_pose = KDL::Frame(KDL::Rotation::Quaternion(0, 0, 0, 1), KDL::Vector(0.3, 0.92, 0.9))); //KDL::Frame(KDL::Vector(0.3, 0.92, 1)));
 
-    int calculateForwardKinematics(const KDL::JntArray &joint_positions, KDL::Frame &end_effector_pose);
+    int calculateForwardKinematics(const KDL::JntArray &joint_positions, KDL::Frame &end_effector_pose, int joint_nbr = -1);
 
     int calculateInverseKinematics(const KDL::JntArray &cur_configuration,
                                    const KDL::Frame &desired_end_effector_pose,