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.

Single-Actuated Camshaft Robot With Multiple Sequential Motions

Abstract

Pipeline inspection in unknown environments is challenging for robots, and various in-pipe crawling robots have been developed in recent years to perform pipeline inspection. Most of these robots comprise multiple parts and require multiple actuators to realize the pipeline locomotion, resulting in complicated system composition and large energy consumption. In this paper, inspired by the crawling principles of earthworm locomotion, we propose a single-actuated camshaft robot that can realize multiple sequential motions for pipeline crawling. The proposed single-actuated camshaft robot contains one actuator and three parts: head anchoring, body elongation, and rear anchoring part. The multiple sequential motions of these three parts are realized based on the cam mechanisms. Umbrella-shaped elastic rubbers are circumferentially around the head and rear anchoring parts. Each part contains a cam bracket. The camshaft’s rotatory motion pushes the cam brackets to generate the axial translational motion, resulting in the umbrella-shaped elastic rubbers being expanded or contracted. The proposed camshaft robot’s expansion and contraction motion are sequentially realized by the phase deviation of the camshafts. First, the structures of the proposed robot are designed. Then, the cam curves are modeled, the expansion/contraction ratio of the rear/head anchoring part is calculated, the phase deviation of the camshafts is determined, and multiple sequential motions of the proposed robot are simulated. Finally, we fabricate the proposed camshaft robot and carry out crawling experiments in pipelines with different shapes and diameters.

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