99 research outputs found
Fluid-filled Soft-bodied Amoeboid Robot Inspired by Plasmodium of True Slime Mold
This paper presents a fluid-filled soft-bodied amoeboid robot inspired by plasmodium of true slime mold. The significant features of this robot are twofold: (1) the robot has fluid circuit (i.e., cylinders and nylon tubes filled with fluid) and truly soft and deformable body stemming from Real-time Tunable Springs (RTSs), the former seals protoplasm to induce global physical interaction between the body parts and the latter is used for elastic actuators; and (2) a fully decentralized control using coupled oscillators with completely local sensory feedback mechanism is realized by exploiting the global physical interaction between the body parts stemming from the fluid circuit. The experimental results show that this robot exhibits adaptive locomotion without relying on any hierarchical structure. The results obtained are expected to shed new light on design scheme for autonomous decentralized control systems
Photometry and Polarimetry of 2010 XC: Observational Confirmation of E-type Near-Earth Asteroid Pair
Asteroid systems such as binaries and pairs are indicative of physical
properties and dynamical histories of the Small Solar System Bodies. Although
numerous observational and theoretical studies have been carried out, the
formation mechanism of asteroid pairs is still unclear, especially for
near-Earth asteroid (NEA) pairs. We conducted a series of optical photometric
and polarimetric observations of a small NEA 2010 XC in 2022 December to
investigate its surface properties. The rotation period of 2010 XC is
possibly a few to several dozen hours and color indices of 2010 XC are
derived as , , and in
the Pan-STARRS system. The linear polarization degrees of 2010 XC are a
few percent at the phase angle range of 58 to 114. We found
that 2010 XC is a rare E-type NEA on the basis of its photometric and
polarimetric properties. Taking the similarity of not only physical properties
but also dynamical integrals and the rarity of E-type NEAs into account, we
suppose that 2010 XC and 1998 WT are of common origin (i.e.,
asteroid pair). These two NEAs are the sixth NEA pair and first E-type NEA pair
ever confirmed, possibly formed by rotational fission. We conjecture that the
parent body of 2010 XC and 1998 WT was transported from the
main-belt through the resonance or Hungaria region.Comment: Resubmitted to AAS Journals. Any comments are welcom
Spectral Type and Geometric Albedo of (98943) 2001 CC21, the Hayabusa2# Mission Target
We conducted optical polarimetry and near-infrared spectroscopy of JAXA's
Hayabusa2# mission target, (98943) 2001 CC21, in early 2023. Our new
observations indicated that this asteroid has a polarimetric inversion angle of
~21 deg, absorption bands around 0.9 and 1.9 um, and a geometric albedo of
0.285 +- 0.083. All these features are consistent with those of S-type but
inconsistent with L-type. Based on this evidence, we conclude that JAXA's
Hayabusa2# spacecraft will explore an S-type asteroid with albedo and size
(0.42-0.56 km when we assume the absolute magnitude of 18.6) similar to (25143)
Itokawa.Comment: 5 pages, 3 figures, Submitted to MNRAS Letter on 2023 April
- …