update bala guide

docs/en/app/bala.md

@@ -66,6 +66,11 @@ C.A.S.E | Plastic ( PC )
 !>3.The CP210X (USB driver) needs to be installed before the EasyLoader is burned. [Click here to view the driver installation tutorial](en/related_documents/M5Burner#install-usb-driver),This program is only available for devices that use the MPU9250/MPU6886. (SH200Q is not supported).
 
 
+## Sensor calibration
+
+If you found that Bala cannot keep balance during use, it can be solved by trying to calibrate the sensor. Press and hold the right C key to start the machine, and release the key after hearing the "drip" sound. The sensor will enter the calibration setting, and keep the host horizontal and still. After 3 seconds, the sensor calibration is completed, and it will automatically enter the balance mode after the calibration is completed.
+
+
 ## PinMap
 
 **Mega328 ISP**Download interface Pin foot definition

docs/zh_CN/app/bala.md

@@ -66,6 +66,11 @@ C.A.S.E | 塑料 ( PC )
 !>3.EasyLoader烧录前需要安装有CP210X（USB驱动程序），[点击此处查看驱动安装教程](zh_CN/related_documents/M5Burner#安装串口驱动)，该程序仅适用于使用MPU9250/MPU6886的设备.(不支持SH200Q).
 
 
+## 传感器进行校准
+
+如果在使用过程中发现BALA无法保持平衡，可通过尝试校准传感器进行解决。按住最右侧C键开机，听到"滴"声后松开按键，传感器会进入校准设置，保持主机水平静止放置，3秒后传感器校准完成，校准完成后会自动进入平衡模式。
+
+
 ## 管脚映射
 
 **Mega328 ISP**下载接口Pin脚定义