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.

Closed-Loop Trajectory Tracking Control of a Cable-Driven Continuum Robot With Integrated Draw Tower Grating Sensor Feedback


Due to the inherent deformability of continuum robots (CRs), closed-loop control strategies of CRs come with some challenges, including sensor integration within a limited dimension and uncertainties with the CR system. In this paper, to obtain the spatial shape information and tip position of a cable-driven CR, a draw tower grating (DTG) sensor is integrated. A shape sensing algorithm is proposed to reconstruct the shape of the CR based on the relation between the DTG sensor and the CR centerline. Then, with the feedback information of the DTG sensor, a damped least-squares (DLS)-based closed-loop controller is implemented to improve the trajectory tracking performance of the CR. To verify the effectiveness of the proposed scheme, comparative experiments are performed.

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