diff --git a/.DS_Store b/.DS_Store
index 2ea5890..2a4bb13 100644
Binary files a/.DS_Store and b/.DS_Store differ
diff --git a/car/.DS_Store b/car/.DS_Store
index 08fc43d..f3eb798 100644
Binary files a/car/.DS_Store and b/car/.DS_Store differ
diff --git a/car/ChassisM2.md b/car/ChassisM2.md
index dd98cd0..491bf5e 100644
--- a/car/ChassisM2.md
+++ b/car/ChassisM2.md
@@ -99,6 +99,19 @@ CANBus串口波特率
 转向轮实时绝对转角，单位rad
 ```
 
+/left_wheel_vel ([std_msgs/Float64](http://docs.ros.org/api/std_msgs/html/msg/Float64.html))
+
+```
+左轮转速，单位m/s。如果需要获得编码器读取的原始转速，只需要将轮速除以车轮半径0.16m即可。
+```
+
+/right_wheel_vel ([std_msgs/Float64](http://docs.ros.org/api/std_msgs/html/msg/Float64.html))
+
+```
+右轮转速，单位m/s。如果需要获得编码器读取的原始转速，只需要将轮速除以车轮半径0.16m即可。
+```
+
+
 #### 2.2.3 服务
 
 /reset_odom ([std_srvs::Empty](http://docs.ros.org/api/std_srvs/html/srv/Empty.html))