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.

Design and Implementation of a Novel Variable Stiffness Actuator With Cam-Based Relocation Mechanism

Abstract

Variable stiffness actuators (VSAs) are widely explored as they could improve the safe performance for human-robot interaction and make the system torque controllable based on the internal compliance. This article presents a novel VSA based on the cam-based relocation mechanism (CRM-VSA), which is utilized to change the locations of pivot and spring of a lever mechanism simultaneously. Consequently, such structure makes the actuator compacted and the stiffness regulation designable, which could help engineers to pursue different demands of stiffness regulation. The simultaneous relocations of the pivot and spring also permit a wide range of adjustable stiffness. By introducing linear guide pairs, the internal friction of the relocations of pivot and spring could be greatly reduced, thus enhancing the energy efficiency. To evaluate the performance of the proposed CRM-VSA, the point-to-point control strategy is developed, which contributes to a higher tracking accuracy and oscillation attenuation at both the start and end points of the trajectory. In addition, the performance of torque controllability is also verified through experiments. These excellent capabilities enable the proposed CRM-VSA to be qualified for constructing a robotic arm toward service applications.
Read More
Journal of Mechanisms and Robotics Open Issues