Latest Papers

ASME Journal of Mechanisms and Robotics

  • Robust Multilegged Walking Robots for Interactions With Different Terrains
    on May 26, 2023 at 12:00 am

    AbstractThis paper explores the kinematic synthesis, design, and pilot experimental testing of a six-legged walking robotic platform able to traverse through different terrains. We aim to develop a structured approach to designing the limb morphology using a relaxed kinematic task with incorporated conditions on foot-environments interaction, specifically contact force direction and curvature constraints, related to maintaining contact. The design approach builds up incrementally starting with studying the basic human leg walking trajectory and then defining a “relaxed” kinematic task. The “relaxed” kinematic task consists only of two contact locations (toe-off and heel-strike) with higher-order motion task specifications compatible with foot-terrain(s) contact and curvature constraints in the vicinity of the two contacts. As the next step, an eight-bar leg image is created based on the “relaxed” kinematic task and incorporated within a six-legged walking robot. Pilot experimental tests explore if the proposed approach results in an adaptable behavior which allows the platform to incorporate different walking foot trajectories and gait styles coupled to each environment. The results suggest that the proposed “relaxed” higher-order motion task combined with the leg morphological properties and feet material allowed the platform to walk stably on the different terrains. Here we would like to note that one of the main advantages of the proposed method in comparison with other existing walking platforms is that the proposed robotic platform has carefully designed limb morphology with incorporated conditions on foot-environment interaction. Additionally, while most of the existing multilegged platforms incorporate one actuator per leg, or per joint, our goal is to explore the possibility of using a single actuator to drive all six legs of the platform. This is a critical step which opens the door for the development of future transformative technology that is largely independent of human control and able to learn about the environment through their own sensory systems.

Two Actuation Methods for a Complete Morphing System Composed of a VGTM and a Compliant Parallel Mechanism


In this paper, a complete morphing system consisting of a variable geometry truss manipulator (VGTM) is presented that is fully covered by a flexible panel skin. Two approaches are studied for the morphing control. The first one is to have the VGTM act as a driving mechanism and the flexible panels as a passive system. In this case, the VGTM is composed of active members and passive lockable members. It is shown that the morphing system can reach the desired shapes through intermediate steps. The second method is to have the flexible panels act as drivers and the VGTM as a passive supporting structure. In this case, the VGTM is only composed of passive lockable members. The morphing system can also achieve the desired poses through several steps. The control strategies of the two methods are discussed along with kinematic analysis, a comparison study is conducted to show their pros and cons, two prototypes are fabricated, and experiments are carried out to verify the feasibility of two actuation methods.
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