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.

Shape-Adaptive Electrostatic Soft Gripper With Transform Mechanism for Multifunctional Grips


This paper proposes a shape-adaptive electroadhesion dielectric elastomer actuator (EA-DEA) pad gripper that can actively adapt to the shape of curved objects and quickly handle various objects by combining an EA pad and a multi-layered DEA driven by electrostatic force. This gripper has a rapid release function capable of detaching thin and light objects in less than 0.2 s with bending motion of multi-layered DEA and reverse polarity voltage. Moreover, combined with a transform mechanism that changes the posture of the EA-DEA pad gripper, a multifunctional gripper handling various objects from thin to irregularly shaped objects is implemented. The high voltage controller is configured to generate the variable and reversible voltages required for the control of the developed gripper. To verify the performance and practicality of the proposed multifunctional gripper system, we demonstrate the gripping task in three modes formed by controlling the EA-DEA pad gripper and the transform mechanism to adapt to the object shape. According to the experimental results, this gripper can reliably and rapidly pick and place various objects, such as thin film, hexahedron, cylinders, spheres, irregular shaped, deformable, and fragile objects corresponding to each mode.

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