1. Download usb_cam package from github [crayon-6af5032f4940b935322077/]   2. [crayon-6af5032f49414339411073/]   then [crayon-6af5032f49416617282227/]   3. create the usb_cam.launch [crayon-6af5032f49417860872267/]   4. [crayon-6af5032f49419720076618/]   that give error: [crayon-6af5032f4941a017030857/]