Has correct visual, collision, and inertia properties. With the inertia values in place, visualization should be similar to theĪt this point in the model creation process, you should have a model that Next add the inertia values for the top link. The following are the inertia values for the base link. The moment of inertia matrix can be computed Which is 1.3kg, and giving the base link a majority (this distribution isĪ guess on our part). We are basing the mass on the specified mass of the Velodyne, We can add inertia to a link by specifying both the mass and inertia Oversized, which is due to our model lacking inertia information. You'll notice that the current inertia boxes are grossly Generally, each purple box should roughly match the size of the link it Right-click on the Velodyne and select View->Inertia. Start by visualizing the current inertia values. Incorrect, or no, inertia values will behave in a strange manner. The physics engine uses inertia information toĬalculate how a model will behave when forces act upon it. (that look like a single cylinder due to their proximity).Īt this point, we have a Velodyne model that lacks dynamic properties suchĪs moments of inertia. Try this now, and you should see two orange cylinders To see, andĭebug, the elements Right-click on a model, and choose How the model will behave when colliding with other models. cdīy default, you will see the elements in a model, which define Run the Velodyne world paused (the -u argument). ThereĪre also a few other graphical tools that can assist the development process, which we will cover over the course of this tutorial. View the model without the physics engine altering the model's pose. When building a new model, it is a good idea to periodically try out smallĬhanges. Below is an screenshot of the Velodyne 2DĬopy the following into the SDF world file directly before the tag. We will Use the Velodyne sensor dimensions to construct a base cylinder andĪ top cylinder. Next, we will add the basics of the Velodyne LiDAR to the SDF world file. Populate the world file with a ground plane and light: a set of laser rays oriented in the vertical fan.
a base cylinder and top cylinder, where the top cylinder spins, and.Manufacturer for specifications, or in the worst case guess.īased on the Velodyne documentation, we will create a sensor that has: Is not available, then you can measure a physical version, ask the
In this case, the Velodyne LiDAR company has provided documentation about their sensors on their website The fist step when creating a new model is to collect information about the This tutorial will focus on the creation of the Velodyne SDF model.
You are an expert tutorial reader (read everything carefully, andĭuring this series of tutorials we will create a We assume you are familiar with using Gazebo and Linux. Process of creating a new simulation feature and contributing the feature to Welcome to the Intermediate Module! This module will guide you through the