Latest Papers

ASME Journal of Mechanisms and Robotics

  • Intuitive Physical Human–Robot Interaction Using an Underactuated Redundant Manipulator With Complete Spatial Rotational Capabilities
    by Audet JM, Gosselin C. on July 21, 2021 at 12:00 am

    AbstractIn this paper, the concept of underactuated redundancy is presented using a novel spatial two-degrees-of-freedom (2-DoF) gravity-balanced rotational manipulator, composed of movable counterweights. The proposed kinematic arrangement makes it possible to intuitively manipulate a payload undergoing 3-DoF spatial rotations by adding a third rotational axis oriented in the direction of gravity. The static equilibrium equations of the 2-DoF architecture are first described in order to provide the required configuration of the counterweights for a statically balanced mechanism. A method for calibrating the mechanism, which establishes the coefficients of the static equilibrium equations, is also presented. In order to both translate and rotate the payload during manipulation, the rotational manipulator is mounted on an existing translational manipulator. Experimental validations of both systems are presented to demonstrate the intuitive and responsive behavior of the manipulators during physical human–robot interactions.

  • Special Section: Mobile Robots and Unmanned Ground Vehicles
    by Reina G, Das TK, Quaglia G, et al. on July 21, 2021 at 12:00 am

    Inspired by the fifth-year anniversary celebration of the homonymous symposium at the International Mechanical Engineering Congress & Exposition (IMECE), this Special Section with ten articles shares the latest research efforts in design, theory, development, and applications for mobile robots and unmanned ground vehicles.

Modeling and Design Exploration of a Tensegrity-Based Twisting Wing

Abstract

This paper presents a modeling and design exploration study of a novel twisting wing whose motion is enabled by a tensegrity mechanism. The aerodynamic characteristics of the twisting wing, which does not require control surfaces to modulate its shape, are compared with those of a conventional wing having a control surface. It is shown via computational fluid dynamics analyses that the twisting wing displays higher lift-to-drag ratio than the conventional wing and hence the twisting wing is more aerodynamically efficient. Subsequently, the torsional tensegrity mechanism, composed of multiple tensegrity cylindrical cells forming a column along the wingspan, is described. A finite element model of the wing incorporating this mechanism is developed. Using the model, a design of experimental study of the influence of the topological parameters of the torsional tensegrity mechanism on the twist angle, mass, and stress in different components of the wing is performed. A wingspan of 142.24 cm and a chord length of 25.31 cm are assumed, corresponding to those of the Carl Goldberg Falcon 56 Mk II R/C unmanned aerial vehicle. For a wing of such dimensions, the maximum achievable twist angle from root to tip per unit mass without any component exceeding their allowable stress is 5.93 deg/kg, which is sufficiently large to allow for effective modulation of the aerodynamic characteristics of the wing. The torsional tensegrity mechanism for this design consists of eight cylindrical cells and four sets of actuator wires along the circumference of each cell.
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