Hi there, when Amber used to bark and lunge at the vacuum, I first had her behind a gate and then had someone distract her with cheerios/a treat. After doing that several times, she would only bark intermittently and that's when I used the "ah-ah" or "leave it" command to get them to stop then praise or give a treat. If they don't stop barking at a command, just wait until you can "catch" their response to stop barking on their own and then praise or treat. She used to bark at the rake (not the broom, I don't know why) as well, however, I first worked with the vacuum because it was indoors and she was able to be behind a gate which is a little more controlled. After we got the vacuum down, she was able to quickly pick up that I don't want her barking at the rake either by just saying "ah-ah" or stepping into her to back her up. I hope that helps.