add chinese

plugin/sensor/README.md

@@ -1,45 +1,34 @@
-# Sensor Plugins
+# 传感器插件（Sensor Plugins）
 
-Custom sensors implemented as [engine
-plugins](https://mujoco.readthedocs.io/en/latest/programming/extension.html#engine-plugins).
+通过[引擎插件](https://mujoco.readthedocs.io/en/latest/programming/extension.html#engine-plugins)实现的自定义传感器。
 
-- [Touch Grid](#touch-grid)
-  - [Example model](#example-model)
-  - [Illustration of fields-of-view in spherical coordinates](#illustration-of-fields-of-view-in-spherical-coordinates)
-  - [Illustration of foveal deformation](#illustration-of-foveal-deformation)
-  - [Illustration combining resolution, fields-of-view and foveal deformation](#illustration-combining-resolution-fields-of-view-and-foveal-deformation)
+- [触觉网格（Touch Grid）](#touch-grid)
+  - [示例模型](#example-model)
+  - [球坐标系下的视场角图示](#illustration-of-fields-of-view-in-spherical-coordinates)
+  - [中央凹形变图示](#illustration-of-foveal-deformation)
+  - [结合分辨率、视场角和中央凹形变的综合图示](#illustration-combining-resolution-fields-of-view-and-foveal-deformation)
 
-- [Touch Stress](#touch-stress)
-  - [Example model with analytical SDF](#example-model-with-analytical-sdf)
+- [触觉应力（Touch Stress）](#touch-stress)
+  - [解析 SDF 示例模型](#example-model-with-analytical-sdf)
 
 ## [Touch Grid](touch_grid.h)
 
-This sensor aggregates contact forces into "taxels": a rectangular array of pixel-like elements.
+该传感器将接触力聚合到“触觉像素（taxels）”中：即类似像素的矩形阵列单元。
 
-A `touch_grid` sensor is associated with a site and senses contact forces and
-torques between the site's parent body and all other bodies. The site's frame
-determines the orientation of the sensor with the same convention used for
-cameras and lights: the sensor points in the frame's **negative-z** direction,
-so the x and y axes correspond to horizontal and vertical, respectively.
+`touch_grid` 传感器与一个 site（位姿点）关联，用于感知该 site 所属的父刚体与所有其他刚体之间的接触力和力矩。site 的坐标系决定了传感器的朝向，采用与相机和光源相同的约定：传感器指向坐标系的 **-z（负 z 轴）**方向，因此 x 轴和 y 轴分别对应水平方向和垂直方向。
 
-The output of the sensor is a stack of 1 to 6 "touch images" corresponding to forces
-and torques in the frame of the sensor. Forces and torques are in the in [z, x,
-y] order, corresponding to the ordering in contact frames: [normal, tangent,
-tangent] and [torsional, rolling, rolling]. Each "taxel" corresponds to an angular bin
-in spherical coordinates, and aggregates all the forces occurring inside this bin, which occur
-between the body in which the sensor's site is defined and any other body.
+该传感器的输出是 1 到 6 个“触觉图像（touch images）”的堆叠，对应于传感器坐标系中的力和力矩。力和力矩按照 [z, x, y] 顺序排列，对应于接触坐标系中的顺序：[法向, 切向, 切向] 和 [扭转, 滚动, 滚动]。每个“触觉像素（taxel）”对应于球坐标系中的一个角度分桶（angular bin），并聚合该分桶内发生的所有接触力（发生在传感器 site 所属刚体与任何其他刚体之间）。
 
-The sensor is parametrized by 6 numbers:
+该传感器由 6 个参数进行参数化：
 
-1. Number of channels, in the order given above. _positive integer in [1 6]_
-2. Horizontal resolution. _positive integer_
-3. Vertical resolution. _positive integer_
-4. Horizontal field-of-view. _positive float in (0, 180] degrees_
-5. Vertical field-of-view. _positive float in (0, 90] degrees_
-6. Foveal deformation. _positive float in [0, 1]_
+1. 通道数（按照上述顺序）：_取值范围为 [1, 6] 的正整数_
+2. 水平分辨率：_正整数_
+3. 垂直分辨率：_正整数_
+4. 水平视场角（FOV）：_角度范围在 (0, 180] 度的正浮点数_
+5. 垂直视场角（FOV）：_角度范围在 (0, 90] 度的正浮点数_
+6. 中央凹形变（Foveal deformation）：_取值范围在 [0, 1] 的正浮点数_
 
-See illustrations below for a visual explanation of the field-of-view and foveal
-deformation parameters. These parameters are passed as plugin config attributes:
+有关视场角和中央凹形变参数的可视化解释，请参见下方的图示。这些参数作为插件的配置属性进行传递：
 
 ```xml
 <mujoco>
@@ -58,57 +47,43 @@ deformation parameters. These parameters are passed as plugin config attributes:
 </mujoco>
 ```
 
-Note the following:
+请注意以下事项：
 
-- The dimensionality of the sensor output is `nchannel * size_x *size_y`.
-- `objtype="site" objname="touch"` specify that the sensor is associated with a
-  site, and the name of the specific site.
-- Field-of-view angles are always in degrees, disregarding the `<compiler>`
-  "angle" directive.
+- 传感器输出的维度为 `nchannel * size_x * size_y`。
+- `objtype="site" objname="touch"` 指定传感器与 site 关联，以及关联的特定 site 名称。
+- 视场角始终以“度”为单位，不受 `<compiler>` 中的 "angle" 指令影响。
 
-### Example model
+### 示例模型
 
 <a href="https://youtu.be/0LOJ3WMnqeA" target="_blank">
- <img src="http://img.youtube.com/vi/0LOJ3WMnqeA/hqdefault.jpg" alt="Watch the video" width="560" height="315"/>
+ <img src="http://img.youtube.com/vi/0LOJ3WMnqeA/hqdefault.jpg" alt="观看视频" width="560" height="315"/>
 </a>
 
-See [touch_grid.xml](../../model/plugin/sensor/touch_grid.xml) to play with the model above.
+请查阅 [touch_grid.xml](../../model/plugin/sensor/touch_grid.xml) 来体验上述模型。
 
-### Illustration of fields-of-view in spherical coordinates
+### 球坐标系下的视场角图示
 
 <img src="images/30-30.png" style="width: 300px;"/>
 <img src="images/180-30.png" style="width: 300px;"/>
 <img src="images/180-90.png" style="width: 300px;"/>
 
-### Illustration of foveal deformation
+### 中央凹形变图示
 
-![foveal deformation](images/fovea.png)
+![中央凹形变](images/fovea.png)
 
-### Illustration combining resolution, fields-of-view and foveal deformation
+### 结合分辨率、视场角和中央凹形变的综合图示
 
-[![touch grid illustration](https://img.youtube.com/vi/YScjmR8LwQI/0.jpg)](https://www.youtube.com/watch?v=YScjmR8LwQI)
+[![touch grid 图示](https://img.youtube.com/vi/YScjmR8LwQI/0.jpg)](https://www.youtube.com/watch?v=YScjmR8LwQI)
 
 ## [Touch Stress](touch_stress.h)
 
-This sensor is based on similar concepts and parametrization as the `touch_grid`,
-while overcoming some of its limitations. In particular, the `touch_grid` can
-only provide sparse information, depending on the number of contact points
-generated. The `touch_stress` sensor can instead generate a high-resolution
-touch image. In order to do this, it requires a signed distance function (SDF)
-of the object that is in contact with the sensor. This is handled internally for
-primitives or it must be declared explicitly in the model using SDF plugins.
+该传感器基于与 `touch_grid` 相似的概念和参数化设计，同时克服了它的一些局限性。具体而言，`touch_grid` 只能提供稀疏信息（取决于生成的接触点数量）。而 `touch_stress` 传感器可以生成高分辨率的触觉图像。为了实现这一点，它需要与传感器接触的物体的符号距离函数（Signed Distance Function, SDF）。对于基本几何图元（primitives），这会在内部自动处理；或者必须使用 SDF 插件在模型中显式声明。
 
-There is one important difference with respect to the `touch_grid`: in this case,
-the force is computed in the local taxel frame and not in the frame of the sensor.
-This allows for a more intuitive interpretation of normal and tangential stresses,
-as shown in the images below.
+与 `touch_grid` 相比有一个重要区别：在此传感器中，力是在局部 taxel 坐标系下计算的，而不是在传感器坐标系下计算的。这使得法向应力和切向应力的物理意义更加直观，如下图所示。
 
-Note that in this case, the absolute values of the stresses reported by the
-sensor are unrelated to the contact forces. They are purely based on geometric
-and kinematic considerations, i.e. the SDF for the normal stress and the sliding
-velocity for the tangential contributions.
+请注意，在这种情况下，传感器报告的应力绝对值与接触力无关。它们纯粹基于几何和运动学考量，即法向应力基于 SDF，切向分量基于滑动速度。
 
-### Example model with analytical SDF
+### 解析 SDF 示例模型
 
 ```xml
 <extension>
@@ -142,8 +117,8 @@ velocity for the tangential contributions.
   </sensor>
 </extension>
 ```
-The images below show a static sphere over a gear described by an analytic SDF
-and the same sphere dragged along the x and y axes.
+
+下图展示了由解析 SDF 描述的齿轮上方的一个静止球体，以及沿 x 轴和 y 轴拖动同一球体时的应力分布：
 
 <img src="images/normal.png" style="width: 300px;"/>
 <img src="images/tangential1.png" style="width: 300px;"/>