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.

Symbolic Differentiation Algorithm for Inverse Dynamics of Serial Robots With Flexible Joints

Abstract

A new symbolic differentiation algorithm is proposed in this paper to automatically generate the inverse dynamics of flexible-joint robots in symbolic form, and results obtained can be used in real-time applications. The proposed method with O(n) computational complexity is developed based on the recursive Newton–Euler algorithm, the chain rule of differentiation, and the computer algebra system. The input of the proposed algorithm consists of symbolic matrices describing the kinematic and dynamic parameters of the robot. The output is the inverse dynamics solution written in portable and optimized code (C-code/Matlab-code). An exemplary, numerical simulation for inverse dynamics of the Kuka LWR4 robot with seven flexible joints is conducted using matlab, in which the computational time per cycle of inverse dynamics is about 0.02 ms. The numerical example provides very good matching results versus existing methods, while requiring much less computation time and complexity.
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