We consider the problem of estimating on line the nonlinear stiffness of flexible transmissions in robots with variable stiffness actuation in agonistic-antagonistic configuration. Stiffness estimation is obtained using a dynamic residual that provides a filtered version of the unmeasured flexibility torques, combining it with a recursive least squares algorithm that fits a polynomial model to ...

Dynamic joint stiffness is a dynamic, nonlinear relationship between the position of a joint and the torque acting about it, which can be used to describe the biomechanics of the joint and associated limb(s). This paper models and quantifies changes in ankle dynamic stiffness and its individual elements, intrinsic and reflex stiffness, in healthy human subjects during isometric, time-varying (T...

This paper investigates the stability of distributed direct user-to-user networked haptic interaction with remote dynamic proxies and passive wave domain communications. Considering fixed communication delays and fixed and low data transmission rate over the network, the paper develops the multirate state space model of the haptic system and uses eigenvalue analysis to determine the maximum sti...

This paper is concerned with the identification problem of two degree of freedom robot arm’s joints’ time-varying stiffness under time-varying torque loads. The industrial robot arms can be simplified into series hinged linkage mechanism. The unrestraint dynamic equation of two degrees of freedom robot arm can be obtained by using analytical mechanics method. The model which was established in ...

The vibration of the vertical system a cold rolling mill is major concern for factory production. In production, it found that thickness control with dynamic stiffness compensation has significant impact on vibration. this work, mechanical hydraulic coupling model was established. MATLAB/Simulink used to simulate and analyze response characteristics structure considering mode position upper cyl...

background: pulse wave velocity (pwv) is widely used for estimating the stiffness of an artery. v arious invasive and non-invasive methods have been developed to determine pwv over the years. in the present research , the non-invasive estimation of the pwv of large arteries was used as an index for arterial stiffness. methods: a dynamic model based on the navier-stokes equations coupled to elas...