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.

Enumerating the Nonisomorphic Configurations of a Modular Reconfigurable Robot

Abstract

By introducing the modular and reconfigurable design, the limbs of a hexapod robot can be assembled into different configurations to meet various task requirements. Contrary to the fixed configuration system, the task capabilities of the modular reconfigurable robot vary with the configurations. This article addresses the problem of the configuration enumeration and configuration expression of a modular reconfigurable robot. First, by establishing the permutation group of the regular hexagon (the base shape of the modular reconfigurable robot) and adopting the Pólya enumeration theorem, the theoretical formula of the nonisomorphic configuration enumeration is derived. Then, considering the change in structural features, equivalence relations based on structural features are defined and the structural feature method (SFM) is proposed to enumerate the nonisomorphic configurations. In addition, to express configurations more intuitively, a senary vertex identification array with the same dimension as the number of modules is presented, which can be transformed from the decimal index of the configuration. Simulation analysis demonstrates that the result of the SFM is consistent with that of the theoretical calculation, which also confirms the effectiveness and accuracy of the two methods applied in the nonisomorphic configuration enumeration of the modular reconfigurable robot.

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