Hi Yucheng_Chen,
I’m sorry to hear about your issue. Let’s try to figure out what is wrong.
Could you tell me when you received ROSbot, how long do you use them before you occur issue and with which firmware version? It should shorten our troubleshooting.
Please try also to connect ROSbot to other screen or using different HDMI cable. Sometimes Asus Tinker Board don’t want to work with some monitors.
Best regards,
Hubert