Why is there noise with my robot?

There are those steps to confirm the problem, 

First, could you please take off the side brush then run the robot to check whether there is noise? If not, may the problem is the side brush. 

If also have noise, could you please take the main brush then run the robot to check whether the problem is the main brush?

If the above methods can not be worked, Please contact support@neakasa.com with those information: ①Order number,② Photo or Video to show the problem. ③SN number of the robot(Remove the dust box)