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We present a spring loaded inverted pendulum (SLIP) based robot leg to enable decoupled swing motion and spring-like behavior. The two SLIP principles (decoupled swing motion and spring-like behavior) allow an improved understanding of robot locomotion and its control. Proposed leg mechanism include one degree of freedom (DOF) straight-line generating mechanism to perform ideal spring-like behavior and the pantograph to amplify that. The spring-like behavior can be implemented using mechanical constraints with Chebyshev linkage and the virtual spring method. For applying the virtual spring method to the radial motion controlled by one actuator, the relationship between the actuator force and radial force acting on the foot end was determined by using a kinematic interpretation. A 1-DOF test bed including the suggested leg was built and tested to verify the decoupled motions. The spring-like leg behavior was demonstrated during the free fall experiment and the experiment in which external force was applied.

The frequent occurrence of disasters has prompted the development of efficient disaster-responding equipment. This study deals with the design of special-purpose machinery and its performance assessment. We defined scenarios through the environmental analysis of disaster situations and expert consulting. We also formulated a set of design specifications by analyzing the objectives of the tasks that must be performed at disaster sites, based on simulated scenarios and existing disaster response machinery. The disaster-responding special-purpose machinery was designed to perform various tasks and display rapid movement in disaster situations. And this paper presents the control structure configured to operate the developed machinery. The performance of the special-purpose machinery was assessed through different scenario tests.

This paper introduces a new hydraulic manipulator with hydraulic-cable driven actuation (HCA) modules for disaster response mobile-manipulation. The hydraulic actuation system has the potential to apply disaster-response application, because it has a higher power-to-weight ratio and robustness to external impacts than electric motor actuation. However, using a conventional hydraulic manipulators is inappropriate because the revolute joint uses conventional actuators, such as linear cylinders and vanes, which have some limitations: 1) linear cylinder: small range of motion, 2) vane: low torque-toweight ratio. To overcome these limitations, we propose new 3DOF manipulator which has a larger workspace than the conventional hydraulic manipulator and comparable payloadto-weight ratio. To this end, we use hydraulic-cable driven actuation modules from our previous research. Experimental results verify the basic performance of the actuator modules and manipulator and their capability to perform various disaster response tasks.

We report a comprehensive analysis of the Electromagnetic (EM) properties of graphene aerogel-based shielding materials prepared by freeze casting. Controlling the freeze casting temperature allows for tailoring the pore sizes of graphene aerogels, which further affects the permittivity and EM shielding properties. To protect the aerogel structures from collapsing during high temperature heat-treatment, we used Melamine sponge (MS) as a supporting strut. Through a comparison with bare aerogels, we find that the presence of MS can significantly modify both the reflection and absorption performances and that an absorption-dominated shielding material can be obtained. After heat-treatment at 1000 °C for two hours, the MS-supported aerogel sample (MS-aero) showed a shielding efficiency of 55.8 dB. Our work shows that the material composition and the microstructural architecture of aerogels crucially influence their electromagnetic shielding efficiency.

The Spring Loaded Inverted Pendulum (SLIP) describes the dynamic walking of humans and animals in a simplified manner. However, realizing such movements by means of a combination of typical articulated legs and linear actuators has some limitations. This paper proposes a leg mechanism that accurately reflects the SLIP based on its mechanical constitution. The SLIP design based leg is able to do decoupled swing motion and extension motion. Also this study has focused on improving the straightness of extension motion.