Robotic surgical assembly comprising: - a slave manipulator comprising: - an actuator ; - at least one pushing device , connected to said actuator - at least one sensor detecting a contact force on said pushing device ; - a position sensing system; - a sterile barrier ; - at least one control unit configured to receive information about said sensor to control said actuator ; - a surgical instrument operated on by said slave manipulator and detachably attached to said slave manipulator and separated from said slave manipulator by said sterile barrier ; said surgical instrument further comprising: - a frame ; - a link (6; 7; 8; 43) articulating in a joint (14; 17) with respect to said frame ; - a tendon , associated to said actuator , having a tendon proximal portion , and a tendon distal portion , secured to said link (6; 7; 8; 43); - at least one transmission device , in contact with said tendon proximal portion , in order to exert a traction action on said tendon ; said transmission device being constrained by a coupling device to have a single degree of freedom of motion with respect to said frame ; - at least one elastic device attached between said instrument frame and said transmission device ; and wherein, whenever said surgical instrument is attached to said slave manipulator: - said at least one pushing device releasably and selectively connects with said transmission device to transmit a pushing action to said transmission device through said sterile barrier ; - said at least one sensor detects a contact force between said pushing device and said transmission device ; - said at least one elastic device biases said at least one transmission device away from said pushing device , so as to exert a traction action on said tendon . - a slave manipulator comprising: - an actuator ; - at least one pushing device , connected to said actuator - at least one sensor detecting a contact force on said pushing device ; - a position sensing system; - a sterile barrier ; - at least one control unit configured to receive information about said sensor to control said actuator ; - a surgical instrument operated on by said slave manipulator and detachably attached to said slave manipulator and separated from said slave manipulator by said sterile barrier ; - an actuator ; - at least one pushing device , connected to said actuator - at least one sensor detecting a contact force on said pushing device ; - a position sensing system; - a sterile barrier ; - at least one control unit configured to receive information about said sensor to control said actuator ; - a surgical instrument operated on by said slave manipulator and detachably attached to said slave manipulator and separated from said slave manipulator by said sterile barrier ; - a frame ; - a link (6; 7; 8; 43) articulating in a joint (14; 17) with respect to said frame ; - a tendon , associated to said actuator , having a tendon proximal portion , and a tendon distal portion , secured to said link (6; 7; 8; 43); - at least one transmission device , in contact with said tendon proximal portion , in order to exert a traction action on said tendon ; said transmission device being constrained by a coupling device to have a single degree of freedom of motion with respect to said frame ; - at least one elastic device attached between said instrument frame and said transmission device ; - said at least one pushing device releasably and selectively connects with said transmission device to transmit a pushing action to said transmission device through said sterile barrier ; - said at least one sensor detects a contact force between said pushing device and said transmission device ; - said at least one elastic device biases said at least one transmission device away from said pushing device , so as to exert a traction action on said tendon . <EOS>