Shared Control of an Electric Wheelchair Considering Physical Functions and Driving Motivation.

Individuals with severe physical impairments have difficulties operating electric wheelchairs (EWs), especially in situations where fine steering abilities are required. Automatic driving partly solves the problem, although excessive reliance on automatic driving is not conducive to maintaining their residual physical functions and may cause more serious diseases in the future. The objective of this study was to develop a shared control system that can be adapted to different environments by completely utilizing the operating ability of the user while maintaining the motivation of the user to drive. The operating characteristics of individuals with severe physical impairments were first analyzed to understand their difficulties when operating EWs. Subsequently, a novel reinforcement learning-based shared control method was proposed to adjust the control weight between the user and the machine to meet the requirements of fully exploiting the operating abilities of the users while assisting them when necessary. Experimental results showed that the proposed shared control system gradually adjusted the control weights between the user and the machine, providing safe operation of the EW while ensuring full use of the control signals from the user. It was also found that the shared control results were deeply affected by the types of users.

The ERA-Related GTPase AtERG2 Associated with Mitochondria 18S RNA Is Essential for Early Embryo Development in Arabidopsis.

The ERA (E. coli RAS-like protein)-related GTPase (ERG) is a nuclear-encoded GTPase with two conserved domains: a GTPase domain and a K Homology (KH) domain. ERG plays a vital role in early seed development in Antirrhinum majus. However, the mechanism that regulates seed development remains unclear. Blasting the genome sequence revealed two homologies of ERG, AtERG1, and AtERG2 in Arabidopsis. In this study, we found that AtERG2 is localized in the mitochondria and binds mitochondrial 18S RNA. Promoter and transcript analyses indicated that AtERG2 was mainly expressed in the leaf vein, trichome, and ovule. The T-DNA insertion lines of AtERG2 showed silique shortage, early seed abortion, and sporophytic maternal effects (SME), in which some seeds arrested in the zygotic stage at 1.5 days after pollination (DAP) and aborted at 2.0 DAP in aterg2-1 +/-. We further showed that the ovules of these arrested seeds presented unusual tissue degradation inside the embryo sacs. Reactive oxygen species (ROS) accumulated at 1.0 and 1.5 DAP in the arrested seeds, and the transcription of several ROS-responsive genes, WRKY40, ANAC017, and AOX1a, was up-regulated in the aterg2-1 +/- arrested seeds at 1.5 and 2.0 DAP, but not in wild-type (WT) and aterg2-1 +/- developed seeds. The cell death-related gene BAG6 was also transcriptionally activated in aterg2-1 +/- seeds arrested at 2.0 DAP. Additionally, the protein level of mitochondria protein ATPase Subunit 6 was lower in 2-DAP siliques of aterg2-1 +/- than it was in those of WT. These results suggested that AtERG2 promotes early seed development by affecting the maturation of the mitochondria ribosome small subunit and mitochondrial protein translation in Arabidopsis.

One Dimensional Input Device of Electric Wheelchair for Persons with Severe Duchenne Muscular Dystrophy.

Persons with severe Duchenne Muscular Dystrophy (DMD) usually have difficult in operating electric wheelchairs (EW) using standard input device due to the lack of muscular power and the deformation of their hands. This paper proposed a novel one dimensional two degree of freedom (1D2F) input device based on the quantitative evaluation of hand function which consists of fingertip force and active range of motion. The validity and the operating features of this device are demonstrated by experiments.