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 and Performance Evaluation of a Spherical Robot Assisted by High-Speed Rotating Flywheels for Self-Stabilization and Obstacle Surmounting


In order to reinforce the operation stability and obstacle capability of a spherical robot, this paper presents a spherical robot with high-speed rotating flywheel, the mechanical structure of which is mainly composed of a spherical shell, a double pendulum on both sides and two high-speed flywheels. The robot has three excitation modes: level running, self-stability operating, and obstacle surmounting. The dynamic characteristics of the pendulum, flywheel, and brake of the robot are discussed through the establishment of kinematic and dynamic model of the spherical robot and the influence of parameters like weight, flywheel speed. and flywheel position on its dynamic characteristics and robot performance is optimized and analyzed in detail. The research results indicate that the two flywheels located in the center of the sphere apart can bring maximum stability gain to the sphere. Finally, the simulation and experiment of the stability gain brought by the high-speed flywheel to the sphere verify that the operation stability of the sphere is effectively improved after using the flywheel, and the robot that stops the flywheel through a brake fixed on the pendulum has better obstacle surmounting performance.
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