This package contains the source code for autopiloting the turtlebot3. The “auto_move_node” will publish velocity data to “/cmd_vel”. It will also use LiDar information from “/scan” from the robot to make turns and avoid obstacles. It offers an obstacle avoidance technique using a lidar range-finder. Turtlebot can detect obstacles in front and 15 degrees to the left and right, and robot will turn 0.5 once it reaches 0.8 meters away from obstacles.
This package detects and calculates the position of a red ball in the world frame. It creates a node “find_center_node”, which subscribes to the topic “/raspicam_node/image” and publishes a geometry_msgs::Point message of the ball x, y coordinate to the topic “/ball_position”. For the object detection part, the camera was first calibrated to obtain the transformation between the pixel coordinate and physical real-world coordinate. With this transformation, we can construct the Perspective Projection Equation and determine the z-axis distance (depth) between the camera and the ball. Lastly, with these parameters, we can then compute the x and y transformation the ball from the camera frame. Median blur and guassian blur are implemented for noise reduction, and hough gradient transform is used for locating the ball. A TF transformation calculation is performed to transfer pixel coordinates of the ball center to world coordinates, which is published as the goal for navigation.
This package contains all the source code and launch file for the navigation section of our project. It includes nodes for simulatively initializing navigation process, publishing navigation points, and transcribing these points into the proper navigation goal messages. This package also contains the URDF for a ball to be placed in the environment. The launch files will launch and load the environment, run all the associated nodes, and load in the map and the ball URDF.
This package contains the launch files for SLAM. It launches Gazebo and RVIZ and loads the robot. Based on the “control_mode” argument, it will also start the “auto_move_node” for autonomous SLAM or “teleop_twist_keyboard” for user-controlled SLAM.
This package contains a dynamic reconfigure file that offers a user interface for terminating the SLAM. The launch file will not only launch the SLAM files in “my_tbot3_sim” package but will also start the server waiting to end SLAM at the user’s request, after which map from SLAM will be saved.
This folder contains all the necessary packages for Turtlebot3, including configuration files, URDF, and launch files.
Drive the robot by publishing geometry_msgs/Twist messages to /cmd_vel. It also subscribes to /scan and uses the LiDar information from the robot to avoid obstacles.
Node for dynamic reconfigure. It offers the user a button for ending the SLAM phase. The program can then initialize a shutdown sequence and save the map from SLAM.
Publish waypoints’ coordinates in geometry_msgs/Point messaage to /fake_goal. It also subscribes to /move_base/result to collect robot’s result.
Publishing a geometry_msgs/PoseWithCovarianceStamped message to /initialpose to initialize robot’s position in the environment. It then subscribes to /odom and /fake_goal to transcribe the waypoint information from geometry_msgs/Point to geometry_msgs/PoseStamped and publishes to “/move_base_simple/goal”.
This launch file offers a basic overview. It will launch an environment in the Gazebo and spawn the model for Turtlebot3. It will also start the teleop interface so that the turtlebot3 can be driven around the environment. Lastly, it will also start RVIZ to display the scan results of the LiDar.
This is the first “real” section of our project. “control_mode” is by default as “auto”, which allows turtlebot to autonomously navigate and avoid obstacles during map building. To manually navigate turtlebot, please add the command “control_mode:=teleop” to use keyboard for robot motion control. This launch file brings up Gazebo, Rviz, SLAM, and nodes “controller_node” and “rqt_reconfigure”. Inside the rqt_reconfigure interface, by choosing “controller_node” and then “Switch_to_navigation” , the dropdown offers an option to terminate SLAM map building process. Selecting “yes(1)” to stops all nodes and map will be saved to the path “/home/the $USER/Downloads/map”.
This is the second section of our project. This launch file will launch Gazebo and RVIZ. Initially, the robot will be placed in a patrol mode and travel around the simulated environment by following a set of pre-determined waypoints. Via a random number generator, at certain time, the robot will be asked to move in front of the ball.