Making of URDF | RViz | ROS with Webots | Robotic Software PicoDegree | Part 2
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- Опубліковано 11 лип 2024
- Wish to get into shoes of Robotics Software Engineer and see the complete cycle of mobile robot development. Also learn and impelement robotics concepts using ROS with a great simulator named Webots. Then you are at the right place. Soft_illusion Channel is back with a new video..!! (A channel which aims to help the robotics community).
#ROS_tutorial_series #Webots_ROS #ROS
0:00 Soft Illusion intro video
0:22 Introduction to URDF
01:27 Recap of Stark
01:47 Joints and Links
02:12 Stark Robot features
03:15 Brainstorm of Stark's links
04:35 Glimpse of end product
06:17 Implementation of URDF branch
09:24 Explanation of XACRO file
10:46 Webots 4-wheeled robot
11:05 Experiments with URDF and Rviz
Important Links:
Github Repo of PicoDegree: github.com/Soft-illusion/Robo...
rosdep to install package dependencies: wiki.ros.org/rosdep
Link of playlist to create custom robot with features like GPS, IMU, Camera etc : • Making Custom Robot in...
In this 2nd video of the Robotics PicoDegree series we look at a simple yet important aspect of developing a robotics system. This concept applies to both stationary as well as mobile robots. I am talking about the URDF. In the most simplest terms, URDF is the model that describes a robot’s physical description to ROS, the rigid links which are connected using joints, or basically what it looks like in real life. It helps to bind the robotic system in a unified frame of reference. It also represents the kinematic and dynamic description of the robot. In the video we will first take a glimpse at the Stark robot’s features and then make a plan for the positions of different links and joints in the robot and determine the fixed joints vs the continuous ones. We finally create a xacro file and visualize the different links and transforms in rviz and also take a look at the TF tree broadcasted by the robust state publisher.
Soft Illusion has come up with this PicoDegree which introduces several concepts of robotics. This tutorial series can be considered a good place to get you started with Robotics Software Engineering.
Before starting the series it's good to get acquainted with ROS as well as Webots. At the end of the tutorial series you will have a fully functional mobile robot which will be able to localize, navigate, avoid obstacles and a lot more.
The tutotial series has been divided into 7 videos:
1. Introduction video - This video shows you how to get started with the github repo that we are developing, and installing the pre-requisites. It also explains how you can either create your own robot or use the Stark robot made by us.
2. Static and Dynamic URDF - This helps ROS understand the actual physical structure of the different links on the robot and where all the sensors and actuators are located.
3. Teleop - This video will show how you can control your robot using the keyboard. The video also explains how Webots services is used to enable the different sensors, and command actuators using sensor values.
4. Mapping - Here you will learn how to have your robot understand and get a feel of its environment using a LiDAR.
5. Navigate - Once the robot undertands it's world, we can use different path planning and optimization algorithms to make it go from point A to point B. This will also include the configuration of costmap and different planners.
6. Obstacle Avoidance - Now when the robot is traveling from point A to B we don’t want it crashing into obstacles or humans. Hence we need good obstacle avoidance algorithms. It will also plan a path around obstacles.
In the last video you met the Stark robot which featured the 4 wheel drive, 2 axis camera movement mechanism, Camera, LiDAR, Linear and rotary actuators, IMU, GPS and Distance Sensor. In this video we will define the links and joints corresponding to each of these features in the robot and then visualize the same in Rviz. The relationship or connection between any parent and child rigid body is described using a joint, on the other hand a link signifies the body itself, hence you’ll always see that a joint connects 2 links. In the stark robot we see that the wheels, distance sensors, gps, imu etc are fixed with respect to the body hence can be considered fixed joints whereas the linear mechanism which moves with respect to the body, is called the continuous joint.
By the end of the video you will learn how to create all of these links on your own, and add visual property to some of the links. You'll also learn how to create these Xyz coordinate tranforms for all the links in the robot.
The robot descriotipn takes this argument, converts the xacro into a URDF and places it in the parameter server.
The robot state publisher then takes the urdf from the parameter server and broadcasts the 3D pose of the robot links to the Transform library in ROS.
![Tutorial on Basics and Advance features of Rviz2 | Webots ROS2 Tutorials | [Tutorial 7]](http://i.ytimg.com/vi/L9lD4QQJ8Cw/mqdefault.jpg)
Excellent 👍
Thank you for your support 🙌🏽
Clear and concise...good work 👏
Thank you .
Glad you liked it .😇
I was following along but my nav_link is still showing as down. No transform from nav_link to base_link. Can you help me fix this?
hey, i was following along and the nav_link for me is still down. no transform from nav_link to base_link. Do i add the link like we did all the others?
great work.. However, i am not able to see the webots simulation because when installing webots the display stops at welcome screen. any possible solution?
hey, for me the nav_link is still down. It says no transform from nav_link to base_link. Can you help me?
How to use the navigation stack with the Pioneer robot (with rosary) and the rplidar a3 sensor (Hector Slam or Gmapping library) Hey, My question is how to use the ros Navigation Stack library to perform autonomous navigation on the pioneer robot that I am using the rosaria library for control, I am also using the rplidar_03 sensor with the hector slam library in the project. If anyone can help me :)
Rarely seen any proper tutorials on ROS let alone tutorials good like this.
But the wheels are fixed? I thought we make the joins as realistic to real life.
Glad you liked the tutorial.
We made this custom robot to mainly get the concepts across on a simple simple model. Yes, the wheels are fixed, (robot turns due to difference in speeds of rotation of the wheels, no steer).
1. If you want to use the wheel for odometer purposes, you can use this same wheel, with another continuous joint on the wheel that’ll rotate with the wheel.
2. If you want steer, you can remodel the proto to have 2 hinge joints for the wheels instead of one.
Do let us know if you want any help with the above.
Oh, now I get it.