MoveIt! is a very popular Motion Planning Framework.
It is a set of packages and tools used for Robotic Manipulation in ROS.
MoveIt! contains software for manipulation, motion planning, kinematics, collision checking etc.
It also has a RViz plugin which can be used to perform Motion Planning from RViz itself.
There are also plenty of Python APIs for Moveit! and ROS which can be used to write ROS Nodes that control Robotic Manipulators.
In this section we are going to learn how to use MoveIt! with ROS and Gazebo.

MoveIt! Architecture

Image from moveit concepts

NOTE: The moveit_commander for python is under development for ROS 2, we will be using other alternatives.

`move_group` Node

This node is the most essential part of MoveIt! which connects all the part of the MoveIt! system together.
This node collects information from the Robot and passes it to various open source plugins available in MoveIt! which are responsible for Motion Planning, IK etc.
This node then passes the instructions from these plugins to the Robot controller which makes the robot move.
Python MoveIt! APIs are used to command the move_group node to perform actions such as pick/place, IK, FK, among others.
move_group uses the Planning Scene Monitor to maintain a planning scene, which is a representation of the world and the current state of the robot.