Arm structure of spraying robot

The invention relates to the technical field of robots, and discloses an arm structure of a spraying robot, which comprises a driving mechanism as well as a working arm, a connecting arm, a first driving assembly, a connecting piece and a distance sensor which are connected to the driving mechanism, the connecting arm is connected between the driving mechanism and the working arm, and the axial direction of the connecting arm coincides with the axial direction of the working arm; a cavity is formed in the connecting arm, a penetrating hole is formed in the side wall, close to the working arm, of the connecting arm and communicates with the cavity, the first driving assembly is connected into the cavity, the connecting piece is provided with a first end and a second end in the extending direction of the connecting piece, and the first end of the connecting piece is connected to the first driving assembly; the second end of the connecting piece extends out of the connecting arm along the penetrating hole to be