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.

An Experimental Investigation on Novel Segmented Omni Wheeled Hybrid Mobile Robot to Assess Obstacle Climbing Capability

Abstract

This article introduces a novel quadrupedal hybrid mobile robot with a segmented omni wheel design capable of climbing obstacles of height greater than its wheel radius. The unique wheel design comprises two parallel coaxial 240-deg segmented omni wheels per leg with independent offset angle control. The transformation from wheel to leg mode and vice versa can be seamlessly achieved by controlling the offset angle between the segmented omni wheels. A series of experiments are carried out to evaluate the robot’s performance for obstacle climbing capability utilizing various wheel end effector designs, and a comparative analysis is presented. The results indicate that the obstacle climbing capability of segmented omni wheel design with zero offset angle is improved by 40.7% compared to standard wheel, and the unique wheel design configuration facilitates seamless staircase climbing capability without any complex control scheme. In addition, statistical studies using the Taguchi method and analysis of variance (ANOVA) are performed on the experimental findings. A linear regression model to predict power consumption has been developed, and the significant factors influencing the robot’s power consumption and stability are presented.

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