Noriaki Ishizuka

Gait Control by Genetic Algorithm for Agricultural Hexapod Walking Robot

Abstract The bio-production of the orchard and the ravine part is done in the inclination ground and unleveled land. The hexapod walking robot, which is stabilized in these field, is suitable for many production works. This study had aimed to develop hexapod walking robots for agriculture. First of all, a small walking robot was made for trial, to form flexible gait that adjusted to unleveled land. Next, straight advancement and turn gait of this robot was formed with genetic algorithms.

Effect of HRT and Support Media on Acidogenic Process by Rotational Drum Fermentation System

The effects of hydraulic retention time (HRT) and the stirring media in the fermentor on RDFS acidogenic process were evaluated via system parameters involving volatile acid (VA) production and volatile solids (VS) degradation under mesophilic conditions. Two sequential experiments were conducted using a bench-scale RDFS. The first set of experiments was performed at HRTs of 15, 20, 25, and 30 days. A first order hydrolysis rate constant of 3.7×10-3 d-1 was calculated at pH values of 4.3 ~ 4.8. VS degradation and total VA (as acetic acid) ranged from 6.7 to 10.4 %, and 13.3 to 16.0 g/L, respectively. Results of the second set of experiments showed that the stirring media accelerated the hydrolysis and acidification processes, with Kh values of 5.3~7.2×10-3 d-1, and the VA spectrum was also influenced. The combined results indicate that pH values have an important effect on the distribution of un-ionized VA and ionized VA. At the same time, accumulation of VA, especially un-ionized VA, inhibits the hydrolysis process regardless of the type of stirring media in the fermentor.

Rotational Drum Reactor System for Dry Methane Fermentation - Startup Characteristics by Use of Dairy Manure -

A rotational drum fermentation system (RDFS) was constructed to develop a dry methane fermentation system for non- or low water-dilution organic waste. Characteristics of a Rotational Drum Fermentation System (RDFS) for solid organic waste were determined. Slightly diluted dairy manure was used as substrate of the RDFS. RDFS improved the mixing of the reactor content. The volatile acid and methane productivity showed the system feasibility for dry methane fermentation. Process parameters such as pH, VA and methane content were evaluated. The effects of operational conditions such as sludge-manure ratios (1:1, 1:2, 1:3, 1:5) and rotation time (30, 60, 120, 240 minutes/day) on the RDFS were determined.