Latest Papers

ASME Journal of Mechanisms and Robotics

  • Design of Reconfigurable Articulated Walking Mechanisms for Diverse Motion Behaviors
    on March 20, 2025 at 12:00 am

    AbstractLegged robots are able to move across irregular terrains and those based on 1-degree-of-freedom planar linkages can be energy efficient but are often constrained by a limited range of gaits which can limit their locomotion capabilities considerably. This article reports the design of novel reconfigurable parallel linkages that not only produce different walking patterns but also realize behaviors beyond locomotion. Experiments with an implemented wearable device able to guide the lower extremity through multiple human-like walking trajectories are presented and the preliminary results validate the proposed approach.

  • Modeling, Kinematics, and Dynamics of a Rigid-Flexible Coupling Spring-Cable-Driven Parallel Robot
    on March 20, 2025 at 12:00 am

    AbstractConventional parallel robots are made of rigid materials for the purpose of fast and accurate localization, exhibiting limited performance in large-scale operations. Inspired by the softness and natural compliance of biological systems, this article proposes a rigid-flexible coupling cable-driven parallel robot. The concept of flexible cable and spring hybrid and working principle are introduced. The kinematics of single module and multiple modules connected in series are analyzed and equations are given, and the Lagrange equation is used to establish dynamic models. Finally, two methods are used to validate the kinematics and dynamics. One is to draw the specific structure with the posture of the end-effector and measure the cable length to compare it with the analytical solution in the kinematic model. The other is to build the structure and joint characteristics in simulink, given the posture of the end-effector and the external force/torque, the cable length and the force applied are compared with those obtained from the dynamic model. The reasonableness of the mechanism and the feasibility of the kinematic and dynamic models are verified.

A 2R1T Redundantly Actuated Parallel Manipulator With an Offset Moving Platform and Fixed Linear Actuators

Abstract

Redundantly actuated parallel manipulators with two rotations and one translation (2R1T RAPMs) have the potential for machining complex surfaces, where a large orientation workspace and high stiffness are required. Considering the advantages of an offset moving platform, such as an enlarged orientation workspace and improved stiffness, a novel 2R1T (2PRR)R-PRS-PSS RAPM with an offset moving platform is proposed in this paper, called M2. Compared with the existing 2R1T RAPM with an offset moving platform, the main advantage of the proposed RAPM is that the heavy motors of four limbs are mounted on the base to reduce the movable mass and improve dynamic response. The kinematical analysis is investigated, including mobility, inverse, forward kinematics, and singularity analysis. Meanwhile, comprehensive evaluations of the properties of the offset moving platform and actuation redundancy are carried out. Compared with M2 RAPM’s form without an offset in moving platform, i.e., no auxiliary platform, and M2 RAPM’s nonredundantly actuated form, the proposed M2 RAPM can achieve a larger orientation workspace and higher stiffness. Particularly, the maximum stiffness of the proposed M2 is 68.8% larger than its form without an auxiliary platform. Finally, the dimensional parameters of the proposed M2 are optimized to obtain an improved satisfactory workspace.

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