I. Use XGO APP software
Connect with the robot dog through bluetooth, then click the gear in the upper right corner to enter the setting page, and choose to run in developer mode. 
Return to the main interface page, a new button appears on the top of the software, click to enter the calibration interface. 
Click "CALIBRATE" button, the servo will be unloaded in time. 
Place the robot dog to the position shown below, it is recommended to put a flat piece of paper underneath, so that the body is flush with the desktop, the thigh and the body are at a 90° angle, and the calf and the thigh are at a 90° angle , the calf is touching the ground. 
Click to "CALIBRATED" button in the APP, the robot dog will return to the original position.
II. Use the driver board to calibrate
Remove the back cover with a hexagonal wrench, and then dial the calibration dial to the ON position. If it is already in the ON position, dial it back and then dial it to the ON position,the servo will be unloaded in time. 
Place the robot dog to the position shown below, it is recommended to put a flat piece of paper underneath, so that the body is flush with the desktop, the thigh and the body are at a 90° angle, and the calf and the thigh are at a 90° angle , the calf is touching the ground.
Then dial the calibration dial back, and the calibration is completed in time, and the robot dog will return to the original position.