From 3120238550829f9ca8d6622456a742eab68b76f0 Mon Sep 17 00:00:00 2001
From: Nikola Banovic <nikola.banovic@b-robotized.com>
Date: Wed, 29 Jul 2026 06:49:49 +0000
Subject: [PATCH] Implement missing virtual function calculate_frame_difference
 from kinematics_interface:master

---
 .../dynamics_interface_kdl.hpp                      |  4 ++++
 .../src/dynamics_interface_kdl.cpp                  | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/dynamics_interface_kdl/include/dynamics_interface_kdl/dynamics_interface_kdl.hpp b/dynamics_interface_kdl/include/dynamics_interface_kdl/dynamics_interface_kdl.hpp
index ae1eb9d..cfa4047 100644
--- a/dynamics_interface_kdl/include/dynamics_interface_kdl/dynamics_interface_kdl.hpp
+++ b/dynamics_interface_kdl/include/dynamics_interface_kdl/dynamics_interface_kdl.hpp
@@ -81,6 +81,10 @@ class DynamicsInterfaceKDL : public dynamics_interface::DynamicsInterface
 
   bool calculate_gravity(const Eigen::VectorXd & joint_pos, Eigen::VectorXd & gravity) override;
 
+  bool calculate_frame_difference(
+    Eigen::Matrix<double, 7, 1> & x_a, Eigen::Matrix<double, 7, 1> & x_b, double dt,
+    Eigen::Matrix<double, 6, 1> & delta_x) override;
+
   bool convert_cartesian_deltas_to_joint_deltas(
     const Eigen::VectorXd & joint_pos, const Eigen::Matrix<double, 6, 1> & delta_x,
     const std::string & link_name, Eigen::VectorXd & delta_theta) override;
diff --git a/dynamics_interface_kdl/src/dynamics_interface_kdl.cpp b/dynamics_interface_kdl/src/dynamics_interface_kdl.cpp
index f122012..243ef57 100644
--- a/dynamics_interface_kdl/src/dynamics_interface_kdl.cpp
+++ b/dynamics_interface_kdl/src/dynamics_interface_kdl.cpp
@@ -471,6 +471,19 @@ bool DynamicsInterfaceKDL::verify_gravity(const Eigen::VectorXd & gravity)
   return true;
 }
 
+bool DynamicsInterfaceKDL::calculate_frame_difference(
+  Eigen::Matrix<double, 7, 1> & x_a, Eigen::Matrix<double, 7, 1> & x_b, double dt,
+  Eigen::Matrix<double, 6, 1> & delta_x)
+{
+  // TODO: implement this, for now, just return false
+  (void)x_a;
+  (void)x_b;
+  (void)dt;
+  (void)delta_x;
+  RCLCPP_ERROR(LOGGER, "calculate_frame_difference is not currently implemented.");
+  return false; 
+}
+
 }  // namespace dynamics_interface_kdl
 
 #include "pluginlib/class_list_macros.hpp"