PV module vibration by robotic cleaning

•Vibration of 6 kinds of PV module under robot cleaning were measured.•A module’s size was the dominant factor in how much it vibrated.•A module’s frame and glass thickness had little influence on its vibration.•Overall the amount of vibration by robot cleaning was small – less than 1 mm.•Strong wind caused more severe module vibrations than the cleaning robot.•Large-format modules and robots that run on the modules may present greater vibration risk.