Latest Papers

ASME Journal of Mechanisms and Robotics

  • Mechanical Characterization of Supernumerary Robotic Tails for Human Balance Augmentation
    on August 31, 2023 at 12:00 am

    AbstractHumans are intrinsically unstable in quiet stance from a rigid body system viewpoint; however, they maintain balance, thanks to neuro-muscular sensory control properties. With increasing levels of balance related incidents in industrial and ageing populations globally each year, the development of assistive mechanisms to augment human balance is paramount. This work investigates the mechanical characteristics of kinematically dissimilar one and two degrees-of-freedom (DoF) supernumerary robotic tails for balance augmentation. Through dynamic simulations and manipulability assessments, the importance of variable coupling inertia in creating a sufficient reaction torque is highlighted. It is shown that two-DoF tails with solely revolute joints are best suited to address the balance augmentation issue. Within the two-DoF options, the characteristics of open versus closed loop tails are investigated, with the ultimate design selection requiring trade-offs between environmental workspace, biomechanical factors, and manufacturing ease to be made.

Modeling of Flexible-Link Manipulators Under Uncertain Parameters Based on Stochastic Finite Element Method


This paper presents a novel approach to obtain the dynamic model of flexible-link manipulators based on the stochastic finite element method. The links and elements of flexible manipulators are affected by uncertainties. The main sources of uncertainties include the variation of mechanical properties. The present research study conveys the following contributions: (i) modeling the uncertain parameters such as the stiffness of the links as an extension of the finite element method based on stochastic fields and the stochastic finite element method, (ii) numerical method to simulate the dynamic response of flexible manipulation with uncertain parameters in the links based on the Monte Carlo simulation (MCS), and (iii) numerical application of the proposed method to the one-link flexible manipulator and two-link flexible manipulator. Numerical simulations illustrate the proposed approach in terms of joint responses and frequency response functions subject to uncertain parameters.

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