thank you for the help. finally, I got it working. I made some mistakes, I list them here, so it may help others.
!! if your Edison module came separately !! (if you see there is a Edison chip set in your package),
you may have the same problems as me (listed below)
1） after you assemble all parts according to the PDF, it will not work, that’s normal. you have to take out robotcore mother board, install Edison module by yourself, here is the instruction.
enter link description here
2) if you installed in Edison module, you need to make sure the USB cable connecting to UE, not UC.
3) MPU orientation sensor to hSens2 !!! I made a mistake here, L3 keep blinking, it wasted me couple of hours.
4) after you start the module, in your mobile device, you can setup WIFI for Edison module.
(I didn’t succeed at this step, I will try it later.)
5) if you have the same situation as me at step#4, you can try to remove Edison module, reconnect USB cable to UC,
6) if you removed Edison, module, and want to make it work, you have to recompile and program robotcore.
you need to register it enter link description here, !!! click the plus sign !!!
you will see an IDE button, click it, create a new project based on ralph_firmware_v3, recompile the project,
upload it robot
7) now, you have the exact same situation as the PDF file mentioned, now you can celebrate the robot.
and it is cool, truly, it can stand on my deck (kids really love it) and it means all of my hardware are ok.
unfortunately, my robot’s footrest has broken already, not sure how it happened,
before trying put back Edison module back to the robot, I need to figure out the other way to support the robot.
I hope this post save someone else’ time (if you have intel edison module).
Good luck every one.