Add convenience function to transform trajectory into msg type

Author: sjahr

moveit_core/trajectory_processing/include/moveit/trajectory_processing/time_optimal_trajectory_generation.h

@@ -189,6 +189,13 @@ class Trajectory
   mutable std::list<TrajectoryStep>::const_iterator cached_trajectory_segment_;
 };
 
+/**
+ * @brief Converts a `trajectory_processing::Trajectory` into a `JointTrajectory` message with a given sampling rate.
+ */
+[[nodiscard]] trajectory_msgs::msg::JointTrajectory
+createTrajectoryMessage(const std::vector<std::string>& joint_names,
+                        const trajectory_processing::Trajectory& trajectory, const int sampling_rate);
+
 MOVEIT_CLASS_FORWARD(TimeOptimalTrajectoryGeneration);
 class TimeOptimalTrajectoryGeneration : public TimeParameterization
 {

moveit_core/trajectory_processing/src/time_optimal_trajectory_generation.cpp

@@ -1310,4 +1310,33 @@ double TimeOptimalTrajectoryGeneration::verifyScalingFactor(const double request
   }
   return scaling_factor;
 }
+
+trajectory_msgs::msg::JointTrajectory createTrajectoryMessage(const std::vector<std::string>& joint_names,
+                                                              const trajectory_processing::Trajectory& trajectory,
+                                                              const int sampling_rate)
+{
+  trajectory_msgs::msg::JointTrajectory trajectory_msg;
+  trajectory_msg.joint_names = joint_names;
+  assert(sampling_rate > 0);
+  const double time_step = 1.0 / static_cast<double>(sampling_rate);
+  const int n_samples = static_cast<int>(trajectory.getDuration() / time_step) + 1;
+  trajectory_msg.points.reserve(n_samples);
+  for (int sample = 0; sample < n_samples; ++sample)
+  {
+    const double t = sample * time_step;
+    trajectory_msgs::msg::JointTrajectoryPoint point;
+    auto position = trajectory.getPosition(t);
+    auto velocity = trajectory.getVelocity(t);
+    auto acceleration = trajectory.getAcceleration(t);
+    for (std::size_t i = 0; i < joint_names.size(); i++)
+    {
+      point.positions.push_back(position[i]);
+      point.velocities.push_back(velocity[i]);
+      point.accelerations.push_back(acceleration[i]);
+    }
+    point.time_from_start = rclcpp::Duration(std::chrono::duration<double>(t));
+    trajectory_msg.points.push_back(std::move(point));
+  }
+  return trajectory_msg;
+}
 }  // namespace trajectory_processing