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.

Design of Robotic Motion Platform Utilizing Continuous Contact Skating


The continuous contact-based skating technique utilizes the sideway movement of the two skates while changing the orientation of the two skates simultaneously. The skates remain in contact with the surface. A mathematical model mimicking a continuous skating technique is developed to analyze the kinematic behavior of the platform. Kinematic and dynamic equations of motion are derived for the nonholonomic constraints. Heuristic-based motion primitives are defined to steer the robotic platform. For the lateral movement of the platform, a creeping-based motion primitive is proposed. A prototype of the robotic platform is developed with three actuated degrees-of-freedom—orientation of two skates and distance between them. A multibody model of the platform is also developed in matlab. Analytical expressions are verified using simulation and experiments. The robotic platform follows the desired motion profiles. The motion profiles include straight-line motion, motion in a circular curve, and lateral creep-like motion of the platform. However, the initial deviation has been observed in both the simulations and experiments due to the slipping of the roller skate at the contact point with the surface. The platform can be effectively used in a structured environment.
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