Nexus 4WD Mecanum Simulator

ROS Repository for the robot description and gazebo simulation of the 4WD Mecanum wheel robot from Nexus Robot: https://www.nexusrobot.com/product/4wd-mecanum-wheel-mobile-arduino-robotics-car-10011.html

Disclaimer:

I'm not affiliated in any way with Nexus Robotics. I just use one of their robot and wanted to write a Gazebo simulation for it.

Usage

Run the simulation for one nexus robot by using the following command line:

roslaunch nexus_4wd_mecanum_gazebo nexus_4wd_mecanum_world.launch

To launch two nexus robots, use the following launch file:

roslaunch nexus_4wd_mecanum_gazebo nexus_4wd_mecanum_multi.launch

Dependencies

• Gazebo7 or Gazebo9
• robot_state_publisher
• urdf
• tf

Packages

• nexus_4wd_mecanum_description
• nexus_4wd_mecanum_gazebo

nexus_4wd_mecanum_description

Robot model description packages. Includes the URDF and the meshes of the robot.

Launch files

• nexus_4wd_mecanum_description.launch: Loads the nexus 4WD mecanum robot description parameter and the robot state publisher.

• nexus_4wd_mecanum_rviz.launch: Loads the nexus 4WD mecanum robot description parameter and a RViz session.

nexus_4wd_mecanum_gazebo

Includes Gazebo plugin for simulating a velocity controller and launch files for running the simulation.

Launch files

• nexus_4wd_mecanum_world.launch: Launches Gazebo and spawn one nexus robot.

  • use_sim_time Tells ROS nodes asking for time to get the Gazebo-published simulation time, published over the ROS topic /clock. Default: true.

  • gui Launch the user interface window of Gazebo. Default: true.

  • headless Enable gazebo state log recording. Default: false.

• nexus_4wd_mecanum_multi.launch: Launches Gazebo and spawn two nexus robots with their namespace. This launch file aims to provide an example for multi-robot simulation.

  • use_sim_time Tells ROS nodes asking for time to get the Gazebo-published simulation time, published over the ROS topic /clock. Default: true.

  • gui Launch the user interface window of Gazebo. Default: true.

  • headless Enable gazebo state log recording. Default: false.

• spawn_one_nexus_4wd_mecanum.launch: To be included in a launch file to spawn a nexus robot.

  • robot_name Robot name used as namespace for the spawned robot. Default: nexus0.

  • pose_x x coordinate (in m) of the robot spawn pose. Default: 0.

  • pose_y y coordinate (in m) of the robot spawn pose. Default: 0.

Gazebo plugin

• nexus_ros_force_based_move:

  Outputs a force and a torque on the base link of a robot, using a velocity command as input and a proportional controller. Includes check for both Gazebo7 and Gazebo9 compatibility.

  • Subscribed topic

    • /cmd_vel (geometry_msgs/Twist)

      Receives velocity command as a Twist message. The plugin will only process the linear velocity on the x and y-axis and the angular velocity on the z-axis

  • Published Topics

    • /odom (nav_msgs/Odometry)

      Odometry from Gazebo model pose and velocity.

    • /front_sensor (sensor_msgs/Range)

      Front ultrasonic range sensor distance

    • /left_sensor (sensor_msgs/Range)

      Left ultrasonic range sensor distance

    • /rear_sensor (sensor_msgs/Range)

      Rear ultrasonic range sensor distance

    • /right_sensor (sensor_msgs/Range)

      Right ultrasonic range sensor distance

To do

• Add wheel velocity controller (only for visual feedback)