Latest Papers

ASME Journal of Mechanisms and Robotics

  • A Small-Scale Integrated Jumping-Crawling Robot: Design, Modeling, and Demonstration
    on June 16, 2025 at 12:00 am

    AbstractThe small jumping-crawling robot improves its obstacle-crossing ability by selecting appropriate locomotion methods. However, current research on jumping-crawling robots remains focused on enhancing specific aspects of performance, and several issues still exist, including nonadjustable gaits, poor stability, nonadjustable jumping posture, and poor motion continuity. This article presents a small jumping-crawling robot with decoupled jumping and crawling mechanisms, offline adjustable gaits, autonomous self-righting, autonomous steering, and certain slope-climbing abilities. The crawling mechanism adopts a partially adjustable Klann six-bar linkage, which can generate four stride lengths and three gaits. The jumping mechanism is designed as a six-bar linkage with passive compliance, and an active clutch allows energy storage and release in any state. The autonomous self-righting mechanism enables the robot to self-right after tipping over, meanwhile providing support, steering, and posture adjustment functions. Prototype experiments show that the designed robot demonstrates good motion stability and can climb a 45 deg slope without tipping over. The robot shows excellent steering performance, with a single action taking 5 s and achieving a steering angle of 11.5 deg. It also exhibits good motion continuity, with an average recovery time of 12 s to return to crawling mode after a jump. Crawling experiments on rough terrain demonstrate the feasibility of applying the designed robot in real-world scenarios.

A Continuously Variable Transmission-Based Variable Stiffness Actuator for pHRI: Design Optimization and Performance Verification

Abstract

Physical human–robot interfaces (pHRIs) enabled the robots to work alongside the human workers complying with the regulations set for physical human–robot interaction systems. A variety of actuation systems named variable stiffness/impedance actuators (VSAs) are configured to be used in these systems’ design. Recently, we introduced a new continuously variable transmission (CVT) mechanism as an alternative solution in configuring VSAs for pHRI. The optimization of this CVT has significant importance to enhance its application area and to detect the limitations of the system. Thus, in this paper, we present a design optimization approach (an adjustment strategy) for this system based on the design goals, desired force, and minimization of the size of the system. To implement such design goals, the static force analysis of the CVT is performed and validated. Furthermore, the fabrication of the optimized prototype is presented, and the experimental verification is performed considering the requirements of VSAs: independent position and stiffness variation, and shock absorbing. Finally, the system is calibrated to display 6 N continuous output force throughout its transmission variation range.

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