From 4d49a88685db09474587429c696fb58e344528b9 Mon Sep 17 00:00:00 2001 From: mohamedsayed18 Date: Thu, 23 Jul 2020 14:57:01 +0300 Subject: [PATCH] grammer fix Signed-off-by: mohamedsayed18 --- tutorials/SDF/car_demo.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tutorials/SDF/car_demo.md b/tutorials/SDF/car_demo.md index 25bed0200..ddaea4196 100644 --- a/tutorials/SDF/car_demo.md +++ b/tutorials/SDF/car_demo.md @@ -170,7 +170,7 @@ Under the `` tag we will add our robot model as follows: 0 0 0 0 0 0 ``` -Here we define the name of our model `vehicle_blue` Which should be a unique name among its sibling(other tags or models) on the same level. Each non-static model must have at least one link designated as the `canonical_link` The implicit frame of the model is attached to this link. The `` tag is used to define the position and orientation of our model and the `relative_to` attribute is used to define the frame of the model relative to any other frame, if the `relative_to` is not defined, the model's `` will be relative to the world. Let's make our pose relative to the `world`. The values inside the pose tag are as follow `X Y Z R P Y` where the `X Y Z` represent the position of the frame and `R P Y` represent the orientation in roll pitch yaw. We set them to zeros which makes the two frames: the model and the world identical. +Here we define the name of our model `vehicle_blue` Which should be a unique name among its sibling(other tags or models) on the same level. Each non-static model must have at least one link designated as the `canonical_link`, the implicit frame of the model is attached to this link. The `` tag is used to define the position and orientation of our model and the `relative_to` attribute is used to define the pose of the model relative to any other frame, if the `relative_to` is not defined, the model's `` will be relative to the world. Let's make our pose relative to the `world`. The values inside the pose tag are as follow `X Y Z R P Y` where the `X Y Z` represent the position of the frame and `R P Y` represent the orientation in roll pitch yaw. We set them to zeros which makes the two frames: the model and the world identical. ### Links forming our robot @@ -201,7 +201,7 @@ We define the first link, the `chassis` of our car and it's pose relative to the ``` -Here we define the inertial properties of chassis like the `mass` and the `` matrix. The values of the inertia matrix for primitive shapes can be found [here](https://en.wikipedia.org/wiki/List_of_moments_of_inertia#List_of_3D_inertia_tensors) +Here we define the inertial properties of chassis like the `mass` and the `` matrix. The values of the inertia matrix for primitive shapes can be calculated using this [tool](https://amesweb.info/inertia/mass-moment-of-inertia-calculator.aspx) #### Visual and collision @@ -236,7 +236,7 @@ We define the shape of our link inside the `` tag as a ``(cuboid) ``` -The `` tag define the collision properties of the link, how our link will react with other objects and the effect of the physics engine on it. +The `` tag defines the collision properties of the link, how our link will react with other objects and the effect of the physics engine on it. **Note**: `` can be different from the visual properties, for example, simpler collision models are often used to reduce computation time. @@ -367,7 +367,7 @@ Let's add a frame for our caster wheel as follows: ``` -We gave our frame name `caster_frame` and attached it to the `chassis` link. Then the `` tag to define the position and orientation of the frame, we didn't use the `relative_to` so the pose is with respect to the frame named in the `attached_to` attribute `chassis` in our case. +We gave our frame name `caster_frame` and attached it to the `chassis` link. Then the `` tag to define the position and orientation of the frame, we didn't use the `relative_to` attribute so the pose is with respect to the frame named in the `attached_to` attribute `chassis` in our case. ### Caster wheel @@ -410,7 +410,7 @@ We gave our frame name `caster_frame` and attached it to the `chassis` link. The Our last link is the `caster` and its pose is with respect to the frame `caster_frame` we defined above. As you could notice we closed the `pose` tag without defining the position or the orientation, in this case the pose of the link is the same as(identity) the frame in `relative_to`. -In the `` and `` we defined a different shape `` which require the `` of the sphere. +In the `` and `` we defined a different shape `` which requires the `` of the sphere. ### Connecting links together(joints) @@ -430,7 +430,7 @@ Our first joint is the `left_wheel_joint`. It takes two attributes the name `nam left_wheel ``` -Every joint connect two links(bodies) together. Here we connect the `chassis` with the `left_wheel`. `chassis` is the parent link and `left_wheel` is the child link. +Every joint connects two links(bodies) together. Here we connect the `chassis` with the `left_wheel`. `chassis` is the parent link and `left_wheel` is the child link. ```xml