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.

Design and Validation of Symmetrical Elastic Elements in Series Elastic Actuator

Abstract

In recent years, the demand for robot joint compliance increased with more complex human–robot interaction scenarios. Series elastic actuators (SEAs) are extensively utilized in multiple fields with abilities to provide accurate force control and energy storage. As the main flexible component in SEA, the accurate modeling of the stiffness of the elastic element is essential. However, the existing stiffness models based on classical Euler–Bernoulli beam theory contain large errors with the actual situation, which increases the difficulty of design. In this paper, a typical elastic element is analyzed by the finite element method to investigate its stiffness properties with different geometric parameters. A more accurate stiffness model is proposed for designing elastic elements. The stiffness model is validated by designed experiments, with a fitting accuracy of 98.27%, which significantly exceeds the stiffness model based on classical beam theory. The proposed stiffness model can be applied to design elastic elements that meet specific stiffness requirements.

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