Slave robot assembly for a robotic surgery system comprising: - a non-sterile robotic manipulator system; - a sterile surgical instrument having a backend portion and a shaft extending from said backend portion; - a sterile adapter, suitable to transmit a plurality of linear actuation actions and a roll action from said non-sterile robotic manipulator system to said sterile surgical instrument; wherein said sterile adapter comprises a frame transmitting the roll action from the non-sterile robotic manipulator system to the sterile surgical instrument, and wherein said frame comprises a proximal coupling device, coupled with the non-sterile robotic manipulator system, and a distal coupling device, coupled with the sterile surgical instrument; and wherein said frame delimits a through opening between said proximal coupling device and said distal coupling device; and wherein said sterile adapter comprises a membrane fixed to said frame, transmitting through the thickness thereof the plurality of localized linear actuation actions from the non-sterile robotic manipulator to the sterile surgical instrument; and wherein the localized linear actuation actions of said plurality are directed orthogonally to a proximal surface of the membrane; and wherein said membrane is elastically stretchable resulting elastically biased towards a substantially flat configuration thereof; and wherein: - said stretchable membrane seals said through opening forming a distal cavity between said stretchable membrane and said distal coupling device; - said distal cavity receives at least a portion of the backend of the sterile surgical instrument; - said distal coupling device comprises at least one abutment surface facing said stretchable membrane and thereby at least partially delimiting said distal cavity; - the surgical instrument abuts against said at least one abutment surface. - a non-sterile robotic manipulator system; - a sterile surgical instrument having a backend portion and a shaft extending from said backend portion; - a sterile adapter, suitable to transmit a plurality of linear actuation actions and a roll action from said non-sterile robotic manipulator system to said sterile surgical instrument; wherein said sterile adapter comprises a frame transmitting the roll action from the non-sterile robotic manipulator system to the sterile surgical instrument, and wherein said frame comprises a proximal coupling device, coupled with the non-sterile robotic manipulator system, and a distal coupling device, coupled with the sterile surgical instrument; and wherein said frame delimits a through opening between said proximal coupling device and said distal coupling device; and wherein said sterile adapter comprises a membrane fixed to said frame, transmitting through the thickness thereof the plurality of localized linear actuation actions from the non-sterile robotic manipulator to the sterile surgical instrument; and wherein the localized linear actuation actions of said plurality are directed orthogonally to a proximal surface of the membrane; and wherein said membrane is elastically stretchable resulting elastically biased towards a substantially flat configuration thereof; and wherein: - said stretchable membrane seals said through opening forming a distal cavity between said stretchable membrane and said distal coupling device; - said distal cavity receives at least a portion of the backend of the sterile surgical instrument; - said distal coupling device comprises at least one abutment surface facing said stretchable membrane and thereby at least partially delimiting said distal cavity; - the surgical instrument abuts against said at least one abutment surface. wherein said sterile adapter comprises a frame transmitting the roll action from the non-sterile robotic manipulator system to the sterile surgical instrument, and wherein said frame comprises a proximal coupling device, coupled with the non-sterile robotic manipulator system, and a distal coupling device, coupled with the sterile surgical instrument; and wherein said frame delimits a through opening between said proximal coupling device and said distal coupling device; and wherein said sterile adapter comprises a membrane fixed to said frame, transmitting through the thickness thereof the plurality of localized linear actuation actions from the non-sterile robotic manipulator to the sterile surgical instrument; and wherein the localized linear actuation actions of said plurality are directed orthogonally to a proximal surface of the membrane; and wherein said membrane is elastically stretchable resulting elastically biased towards a substantially flat configuration thereof; and wherein: - said stretchable membrane seals said through opening forming a distal cavity between said stretchable membrane and said distal coupling device; - said distal cavity receives at least a portion of the backend of the sterile surgical instrument; - said distal coupling device comprises at least one abutment surface facing said stretchable membrane and thereby at least partially delimiting said distal cavity; - the surgical instrument abuts against said at least one abutment surface. - said stretchable membrane seals said through opening forming a distal cavity between said stretchable membrane and said distal coupling device; - said distal cavity receives at least a portion of the backend of the sterile surgical instrument; - said distal coupling device comprises at least one abutment surface facing said stretchable membrane and thereby at least partially delimiting said distal cavity; - the surgical instrument abuts against said at least one abutment surface.