We claim the ornamental design for an autonomous mobile robot, as shown and described.
FIG. 1 is a top perspective view of an autonomous mobile robot of the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a first side view thereof;
FIG. 5 is a second side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of autonomous mobile robot is included for the purpose of illustrating environment and forms no part of the claimed design. Additionally, the unevenly broken lines in the drawings define the limits of the claimed design.