Interactive human-robot system with a control algorithm to estimate the human stiffness

The robot system (10), comprising: a robot (14) supplied with power elements (21, 25), said robot (14) for moving a payload (30) using the power-supplied members (21, 25) during operation with a proportional response an input force (F) by a human operator (12) is arranged; an operator interface robot (16) comprising a plurality of sensors (22, 32, 40, 42) which is for measuring a predetermined set of operator input values ​​that comprise the input force (F), designed; and is a controller (23) responsive and arranged on the input force (F) to the power-supplied members (21, 25) to operate, wherein the controller (23) for detecting a changing stiffness value of the human operator (12) is operable, during operation using the set of operator input values; wherein the controller (23) automatically adjusts a level of the control sensitivity of the robot (14) using the varying stiffness value, to thereby optimize the steering stability; and wherein the controller (23) the level of the control sensitivity is automatically increased when the rigidity value decreases or as the stiffness value is less than a calibrated threshold value, and the level of control sensitivity automatically reduced if the stiffness value increases, or if the rigidity value exceeds the calibrated threshold.