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.

Passive Aligning of Ribbon Cable in Sliding Surface Gripper for Assembly Task


A passive aligning strategy for the assembly task of a ribbon cable is presented using a sliding surface gripper. Once the gripper grasps the ribbon cable, the sliding surface of the gripper pulls the cable in one direction, and at the end of the pulling process, the box-shaped structure of the fingertip of the gripper passively aligns the cable to a predictable pose. The relationship between the alignment speed of the cable on the sliding surface and the grasping force was modeled and verified by experiments. The maximum position error of the ribbon cable connector aligned by the proposed method was 0.7 mm, which was smaller than the mating tolerance between typical male and female connectors. The mating of the connectors was successfully conducted with an industrial robot whose repeatability is less than a millimeter. The entire assembly process of ribbon cable connectors, including visual recognition of the ribbon cable pose, grasping and aligning of the ribbon cable, and mating a pair of cable connectors, was successfully implemented.
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