Add MTC to concepts (#809)

Co-authored-by: Sebastian Castro <[email protected]>
Co-authored-by: Ashton Larkin <[email protected]>

Author: 3 people

doc/concepts/concepts.rst

@@ -11,5 +11,6 @@ Concepts
    move_group
    planning_scene_monitor
    trajectory_processing
+   moveit_task_constructor/moveit_task_constructor
 
 .. image:: /_static/images/moveit_pipeline.png

doc/concepts/moveit_task_constructor/_static/images/alternatives.png

@@ -0,0 +1,45 @@
+.. _Connecting Stages:
+
+#################
+Connecting Stages
+#################
+
+| MTC provides only one connecting stage called Connect.
+| A connect stage solves for a feasible trajectory between the start and goal states.
+
+Connect
+-------
+
+| The ``Connect`` stage connects two stages by finding a motion plan between the start and end goal given by the adjacent stages.
+| The default cost term depends on path length.
+| The default planning time for this stage is 1.0s.
+
+.. list-table:: Properties to be set by user
+   :widths: 25 100 80
+   :header-rows: 1
+
+   * - Property Name
+     - Function to set property
+     - Description
+   * - merge_mode
+     -
+     - Define the merge strategy to use when performing planning operations. This parameter is an enum type. Can be SEQUENTIAL(Store sequential trajectories) or WAYPOINTS(Join trajectories by their waypoints). Default is WAYPOINTS.
+   * - path_constaints
+     - void setPathConstraints(moveit_msgs/Constraints path_constraints)
+     - Constraints to maintain during trajectory
+   * - merge_time_parameterization
+     -
+     - Default is TOTG (Time-Optimal Trajectory Generation). Information about TOTG is available in the :ref:`Time Parameterization tutorial <doc/examples/time_parameterization/time_parameterization_tutorial:Time Parameterization Algorithms>`
+
+`API doc for Connect <https://ros-planning.github.io/moveit_task_constructor/_static/classmoveit_1_1task__constructor_1_1stages_1_1Connect.html>`_.
+
+Code Example
+
+.. code-block:: c++
+
+  auto node = std::make_shared<rclcpp::Node>();
+  // planner used for connect
+  auto pipeline = std::make_shared<solvers::PipelinePlanner>(node, "ompl", "RRTConnectkConfigDefault");
+  // connect to pick
+  stages::Connect::GroupPlannerVector planners = { { "arm", pipeline }, { "gripper", pipeline } };
+  auto connect = std::make_unique<stages::Connect>("connect", planners);