01773nas a2200193   4500008004100000245008200041210006900123260001200192520105400204653003501258653003601293653002001329653001801349100001701367700002001384700002101404700002301425856013101448       2022                        eng d00aForce/Torque-Sensorless Joint Stiffness Estimation in Articulated Soft Robots0 aForceTorqueSensorless Joint Stiffness Estimation in Articulated   c05/20223 a<p>Currently, the access to the knowledge of stiffness values is typically constrained to a-priori identified models or datasheet information, which either do not usually take into account the full range of possible stiffness values or need extensive experiments. This work tackles the challenge of stiffness estimation in articulated soft manipulators, and it proposes an innovative solution adding value to the previous research by removing the necessity for force/torque sensors and generalizing to multi-degree-of-freedom robots. Built upon the theory of unknown input-state observers and recursive least-square algorithms, the solution is independent of the actuator model parameters and its internal control signals. The validity of the approach is proven analytically for single and multiple degree-offreedom robots. The obtained estimators are first evaluated via simulations on articulated soft robots with different actuations and then tested in experiments with real robotic setups using antagonistic variable stiffness actuators.</p>
10aCalibration and Identification10aCompliant Joints and Mechanisms10aFlexible Robots10aSafety in HRI1 aTrumic, Maja1 aGrioli, Giorgio1 aJovanovic, Kosta1 aFagiolini, Adriano  uhttps://www.centropiaggio.unipi.it/publications/forcetorque-sensorless-joint-stiffness-estimation-articulated-soft-robots.html