00514nas a2200121 4500008004100000245009400041210006900135100001300204700001700217700001500234700002300249856012000272 2019 eng d00aA real-time identification and tracking method for the musculoskeletal model of human arm0 arealtime identification and tracking method for the musculoskele1 aFang, C.1 aAjoudani, A.1 aBicchi, A.1 aTsagarakis, N., G. uhttp://95.110.227.47/publications/real-time-identification-and-tracking-method-musculoskeletal-model-human-arm.html02059nas a2200193 4500008004100000245007500041210006900116260001200185300001200197490000600209520150800215653001201723653001301735100001301748700001701761700001501778700002301793856004901816 2017 eng d00aOnline Model Based Estimation of Complete Joint Stiffness of Human Arm0 aOnline Model Based Estimation of Complete Joint Stiffness of Hum c01/2018 a84 - 910 v33 a

The endpoint stiffness of the human arm has been long recognized as a key component ensuring the quasi-static stability of the arm physical interactions with the external world. Similarly, the understanding of the joint stiffness behavior can provide complementary insights, e.g., on the underlying stiffness regulation principles across different joints including the nullspace stiffness profiles. Traditionally, the experimental modeling and estimation of the human arm joint stiffness is achieved by the transformation of the identified arm endpoint stiffness to the joint coordinates. Due to the underlying kinematic redundancy, the obtained joint stiffness matrix is rank-deficient which implies that the information in the joint stiffness matrix is incomplete. While in robotics applications this issue can be addressed by designing a desired nullspace stiffness behavior through appropriate projections, the use of a similar technique in the identification of human joint stiffness profile is meaningless. Hence, the first objective of this work is to address this issue by developing a novel technique to identify the complete and physiologically meaningful joint stiffness of human arm. Second, we present a model-based online estimation technique to estimate the seven-dimensional complete joint stiffness in various arm poses and activation levels of the two dominant arm muscles that correspond to the geometric and volume modifications of the joint stiffness profile, respectively.

10aHaptics10aRobotics1 aFang, C.1 aAjoudani, A.1 aBicchi, A.1 aTsagarakis, N., G. uhttp://ieeexplore.ieee.org/document/7990237/00567nas a2200145 4500008003900000245007500039210006900114260004700183653001300230100001300243700001700256700001500273700002300288856011000311 2017 d00aOnline Model Based Estimation of Complete Joint Stiffness of Human Arm0 aOnline Model Based Estimation of Complete Joint Stiffness of Hum aVancouver, Canada, September 24–28, 201710aRobotics1 aFang, C.1 aAjoudani, A.1 aBicchi, A.1 aTsagarakis, N., G. uhttp://95.110.227.47/publications/online-model-based-estimation-complete-joint-stiffness-human-arm.html-000538nas a2200145 4500008004100000245012800041210006900169260001200238490000700250100001700257700001300274700002300287700001500310856006700325 2017 eng d00aReduced-Complexity Representation of the Human Arm Active Endpoint Stiffness for Supervisory Control of Remote Manipulation0 aReducedComplexity Representation of the Human Arm Active Endpoin c11/20170 v371 aAjoudani, A.1 aFang, C.1 aTsagarakis, N., G.1 aBicchi, A. uhttps://journals.sagepub.com/doi/full/10.1177/027836491774403502477nas a2200181 4500008004500000245010600045210006900151260004900220300001600269520185200285653001202137653001302149100001702162700001302179700002002192700001502212856006802227 2015 engldsh 00aA Reduced-Complexity Description of Arm Endpoint Stiffness with Applications to Teleimpedance Control0 aReducedComplexity Description of Arm Endpoint Stiffness with App aHamburg, Germany, 28 Sept - 2 Oct 2015bIEEE a1017 - 10233 a

Effective and stable execution of a remote task in an uncertain environment requires that the task force and position trajectories of the slave robot be appropriately commanded. To achieve this goal, in teleimpedance control, a reference command which consists of the stiffness and position profiles of the master is computed and realized by the compliant slave robot in real-time. This highlights the need for a suitable and computationally efficient tracking of the human limb stiffness profile in real-time. In this direction, based on the observations in human neuromotor control which give evidence on the predominant use of the arm configuration in directional adjustments of the endpoint stiffness profile, and the role of muscular co-activations which contribute to a coordinated stiffening of the task stiffness in all directions, we propose a novel and computationally efficient model of the arm endpoint stiffness behaviour. With the purpose of real-time tracking of the human arm kinematics, an arm triangle is introduced using three body markers at the shoulder, elbow and wrist joints. In addition, a co-contraction index is defined using muscular activities of a dominant antagonistic muscle pair. Calibration and identification of the model parameters are carried out experimentally, using perturbation-based arm endpoint stiffness measurements in different arm configurations and co-contraction levels of the chosen muscles. Results of this study suggest that the proposed model enables the master to naturally execute a remote task by modulating the direction of the major axes of the endpoint stiffness and its volume using arm configuration and the co-ativation of the involved muscles, respectively.

10aHaptics10aRobotics1 aAjoudani, A.1 aFang, C.1 aTsagarakis, N G1 aBicchi, A. uhttp://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7353495