Mobile Robot Utilizing Arm Rotations – Performance of Mobile Robot Under a Gravity Environment –

In this research, we have considered a mobile robot that can start to move by utilizing rotations of the two arms. This robot consists of two rotating arms and a body. Additionally, it has a device that can fix the body to a platform constructed on a certain wall or floor. In our previous study, we investigated the performance of a robot that could move in a planar space without friction or gravity through several numerical simulations. In this study, we investigate the performance of the mobile robot under a gravity environment. While the body is fixed to a starting platform, the mobile robot can store kinetic energy by rotating its arms. When the body is released from the starting platform, the mobile robot hops to the subsequent platform. We consider a scheme to control the hopping direction of the mobile robot and a scheme to reduce the collision impact against the subsequent platform. Thereafter, we verify the feasibility of the proposed schemes through numerical simulations.

The widely occurring brittlestar Ophiactis savignyi (Amphilepidida: Ophiactidae) as an epibiont on loggerhead sea turtle, Caretta caretta

We describe the first occurrence of the widely occurring brittlestar Ophiactis savignyi (Müller Troschel, 1842) as epibionts on Caretta caretta (Linnaeus, 1758), the loggerhead sea turtles. On the sea turtle epibionts, the coronulid barnacles were well studied as listed in Hayashi (2013), and recently some crustaceans were collected from loggerhead sea turtles and described as new species (Tanabe et al. 2017; Tanaka and Hayashi 2019). In contrast, echinoderm epibionts listed from sea turtles are poorly understood (Table 1) and this study represents the novel discovery of an ophiuroid, which was not previously known to occur on the surface of this species.

Centipede Type Robot i-CentiPot: From Machine to Creatures

In this study, we have developed a centipede-like multi-legged robot named i-CentiPot. This robot was developed to demonstrate our concept presented in the CREST project. In the project, we show that the existence of implicit control is important. i-CentiPot plays the part of the anchor example for our project.*

* This article is a translation from the article: K. Osuka et al., “Centipede type robot i-CentiPot: From machine to creatures,” The 8th Conf. of Transdisciplinary Federation of Science and Technology, D-2-4, 2017 (in Japanese).

Chelonocytherois omutai gen. et sp. nov. (Crustacea: Ostracoda) from the back of loggerhead sea turtles

Chelonocytherois omutai gen. et sp. nov., is found on the back of female loggerhead sea turtles on the nesting beach of the Yakushima Island, Kagoshima Prefecture, Japan. The present study provides the first species-level identification and description of Ostracoda as sea turtle epibionts. The new genus and species, which belongs to the family Paradoxostomatidae Brady and Norman, 1889, can clearly be distinguished from other genera by the morphology of the carapace and the appendages. Especially, the quite large sieve structure on the pore system of the carapace is characteristic to this genus. Although a similar structure is also found in the commensal ostracod genus Redekea de Vos, 1953, the new genus has distinctive mandibular and maxillular morphologies. From examination of the appendages, C. omutai gen. et sp. nov. seems to be an epibiotic species associated with sea turtles, but not a strictly commensal species. Additionally, the nearly complete 18S rRNA gene sequence is determined for C. omutai gen. et sp. nov. for future molecular phylogenetic studies. Since the sea turtles migrate across the oceans in their ontogenetic stages, they may play a role as a long-distance dispersal vector for C. omutai gen. et sp. nov.

Posture Control of Two Link Torque Unit Manipulator Considering Influence of Viscous Friction on Joints

In this research, we consider a posture control problem of a planar two-link torque unit manipulator under a viscous friction condition. The torque unit is a module that consists of an electric motor and a reaction wheel. The friction caused by the presence of a viscous environment cannot be ignored in the real system. In this report, we first clarify the relation between the angle of links and the angular momentum of the reaction wheels under the viscous friction condition. Next, we try to control the first link at an arbitrary reference position without taking into consideration the angle of the second link. The angle of the first link can be controlled by changing the viscous friction condition between the first link and the base. Moreover, we attempt to control the second link at an arbitrary reference position by using the residual angular momentum of the reaction wheel at the second link. Finally, we demonstrate the feasibility of the proposed method by conducting a verification experiment.