Aerial　physical　interaction　is　a　promising　field　for　unmanned　aerial　vehicles　in　future　applications.　This　paper　presents　a　novel　paradigm　for　automatic　aerial　contact-based　sliding　interaction　(inspection/cleaning)　tasks　in　aerial　robotics　allowing　a　3D　force　with　a　constant　norm　to　be　applied　on　generic　surfaces　with　unknown　geometry.　The　interaction　task　is　achieved　by　a　fully-actuated　hexarotor　equipped　with　a　rigidly　attached　end-effector　under　a　passivity-based　geometric　impedance　controller　and　a　new　sliding-mode　extended　state　observer　to　estimate　the　interaction　wrench.　In　order　to　increase　the　observer　performance　and　reduce　the　estimation　chattering　phenomenon,　the　observer　is　innovatively　incorporated　with　a　super-twisting　algorithm　and　a　sigmoid　function　with　a　switching　gain　being　adaptively　updated　by　a　fuzzy　logic　system.　A　detailed　stability　analysis　for　the　observer　is　presented　based　on　the　Lyapunov　stability　theory.　The　proposed　control　approach　is　validated　in　several　simulations　in　which　we　try　to　accomplish　the　aerial　physical　sliding　interaction　task　with　different　types　of　objects　under　various　sliding　speeds.