API for offline use of dynamics model

include/franka/model.h

@@ -63,6 +63,20 @@ class Model {
    */
   explicit Model(franka::Network& network);
 
+  /**
+   * Creates a new Model instance.
+   *
+   * This constructor is for internal use only.
+   *
+   * @see Robot::loadModel
+   *
+   * @param[in] pathToLib file path to load model library from (instead of downloading from the robot)
+   *
+   * @throw ModelException if the model library cannot be loaded.
+   */
+  explicit Model(const std::string& pathToLib);
+
+
   /**
    * Move-constructs a new Model instance.
    *

include/franka/robot.h

@@ -663,6 +663,12 @@ class Robot {
 
   class Impl;
 
+  /**
+   * Save the dynamics model library from the robot for offline use to the given path
+   *
+   */
+   void downloadModelLibrary(const std::string& toFile);
+
  private:
   std::unique_ptr<Impl> impl_;
   std::mutex control_mutex_;

src/model.cpp

@@ -22,6 +22,7 @@ Frame operator++(Frame& frame, int /* dummy */) noexcept {
 }
 
 Model::Model(Network& network) : library_{new ModelLibrary(network)} {}
+Model::Model(const std::string& pathToLib) : library_{new ModelLibrary(pathToLib)} {}
 
 // Has to be declared here, as the ModelLibrary type is incomplete in the header
 Model::~Model() noexcept = default;

src/model_library.cpp

@@ -7,7 +7,10 @@
 namespace franka {
 
 ModelLibrary::ModelLibrary(franka::Network& network)
-    : loader_(LibraryDownloader(network).path()),
+    : ModelLibrary(LibraryDownloader(network).path()) {}
+
+ModelLibrary::ModelLibrary(const std::string& cachepath)
+    : loader_(cachepath),
       body_jacobian_joint1{reinterpret_cast<decltype(&Ji_J_J1)>(loader_.getSymbol("Ji_J_J1"))},
       body_jacobian_joint2{reinterpret_cast<decltype(&Ji_J_J2)>(loader_.getSymbol("Ji_J_J2"))},
       body_jacobian_joint3{reinterpret_cast<decltype(&Ji_J_J3)>(loader_.getSymbol("Ji_J_J3"))},

src/model_library.h

@@ -13,6 +13,7 @@ namespace franka {
 class ModelLibrary {
  public:
   ModelLibrary(Network& network);
+  ModelLibrary(const std::string& cachepath);
 
  private:
   LibraryLoader loader_;

src/robot.cpp

@@ -3,10 +3,12 @@
 #include <franka/robot.h>
 
 #include <utility>
+#include <fstream> 
 
 #include "control_loop.h"
 #include "network.h"
 #include "robot_impl.h"
+#include "library_downloader.h"
 
 namespace franka {
 
@@ -306,4 +308,11 @@ Model Robot::loadModel() {
   return impl_->loadModel();
 }
 
+void Robot::downloadModelLibrary(const std::string& toFile) {
+    std::ofstream dst(toFile, std::ios::binary);
+    LibraryDownloader downloaderObj(*(impl_->network_));
+    std::ifstream  src(downloaderObj.path(), std::ios::binary);
+    dst << src.rdbuf(); 
+}
+
 }  // namespace franka

src/robot_impl.h

@@ -51,6 +51,8 @@ class Robot::Impl : public RobotControl {
 
   Model loadModel() const;
 
+  std::unique_ptr<Network> network_;
+
  protected:
   bool motionGeneratorRunning() const noexcept;
   bool controllerRunning() const noexcept;
@@ -73,7 +75,6 @@ class Robot::Impl : public RobotControl {
   research_interface::robot::RobotState receiveRobotState();
   void updateState(const research_interface::robot::RobotState& robot_state);
 
-  std::unique_ptr<Network> network_;
 
   Logger logger_;