Latest Papers

ASME Journal of Mechanisms and Robotics

  • Integrated Wheel–Foot–Arm Design of a Mobile Platform With Linkage Mechanisms
    on March 20, 2024 at 12:00 am

    AbstractInspired by lizards, a novel mobile platform with revolving linkage legs is proposed. The platform consists of four six-bar bipedal modules, and it is designed for heavy transportation on unstructured terrain. The platform possesses smooth-wheeled locomotion and obstacle-adaptive legged locomotion to enhance maneuverability. The kinematics of the six-bar bipedal modules is analyzed using the vector loop method, subsequently ascertaining the drive scheme. The foot trajectory compensation curve is generated using the fixed-axis rotation contour algorithm, which effectively reduces the centroid fluctuation and enables seamless switching between wheels and legs. When encountering obstacles, the revolving linkage legs act as climbing arms, facilitating seamless integration of wheel, foot, and arm. A physical prototype is developed to test the platform on three typical terrains: flat terrain, slope, and vertical obstacle. The experimental results demonstrated the feasibility of the platform structure. The platform can climb obstacles higher than its own height without adding extra actuation.

Untethered Microrobot Motion Mechanism With Increased Longitudinal Force

Abstract

The importance of an untethered microrobotic platform that can operate on high flowrate microfluidic channels for in vitro applications is increasing rapidly. This article presents a method to manipulate a microrobot in a fluidic chip when high flowrates (4 ml/min, 82.304 mm/s) are applied. This method is based on a novel permanent magnet-based diamagnetic levitation configuration. This configuration includes a thin layer of pyrolytic graphite, which is placed just below the microrobot. In this way, microrobot stability and manipulation capability are increased. Also, we aim to increase the longitudinal forces imposed on the microrobot to withstand the drag force proportional to the flowrate. Hence, magnetic field lines are generated more linearly around the microrobot by a different combination of permanent magnets. The proposed magnetic configuration, named “KERKAN configuration,” significantly improves the microrobot’s longitudinal forces. In this configuration, two different ring-shaped ferromagnetic magnets are used. One of the magnets has a smaller diameter than the other magnet. A combination of one smaller and one bigger magnet is placed above and below the microrobot. To validate the advantages of this configuration, analytical and simulation studies are conducted. Their results are then compared with experimental results. Experimental results are on par with analytical and simulation studies. KERKAN configuration has a lower displacement than the next best configuration at the highest flowrate we applied (relatively 3301 μm, %21.8).
Read More
Journal of Mechanisms and Robotics Open Issues