Simultaneous Optimization of a Wheeled Mobile Robot Structure and a Control Parameter

A wheeled mobile mechanism with a passive and/or active linkage mechanism for traveling in the outdoor environment is developed and evaluated. In our previous research, we developed a wheeled mobile robot which has six wheels and a passive linkage mechanism, and its maneuverability was experimentally verified. The ability to climb over a 0.20 [m] high bump, which is twice height of the wheel diameter of 0.10 [m], was achieved, and the mobile robot can climb up continuous steps of 0.15 [m] high. In this research, we optimized the mobile robot linkage mechanisms and a controller parameter by evolutionary algorithm and dynamics engine in numerical simulations. The evolutionary algorithm employed in this research is Genetic Algorithm, and Open Dynamics Engine is used for dynamics calculation. To optimize the linkage mechanism and a controller parameter, we investigated outdoor environment for the mobile robot, for example obstacles, steps, and stairs. And, we selected typical three kinds of outdoor environments, 0.20 [m] high bump, right angle stairs of 0.15 [m] high, and angled stairs of 0.15 [m] high. In the numerical simulations, though the mobile robot using parameters which express our existing robot could climb up/down the 0.20 [m] high bump, but it could not achieve climbing up/down the two kinds of stairs. On the other hand, the optimized parameter mobile robot could climb up/down the three kinds of typical environments

Evaluation of the relationships between saliency maps and keypoints

The saliency map is proposed by Itti et al., to represent the conspicuity or saliency in the visual field and to guide the selection of attended locations based on the spatial distribution of saliency, which works as the trigger of bottom-up attention. If a certain location in the visual field is sufficiently different from its surrounding, we naturally pay attention to the characteristic of visual scene. In the research of computer vision, image feature extraction methods such as Scale-Invariant Feature Transform (SIFT), Speed-Up Robust Features (SURF), Binary Robust Invariant Scalable Keypoint (BRISK) etc., have been proposed to extract keypoints robust to size change or rotation of target objects. These feature extraction methods are inevitable techniques for image mosaicking and Visual SLAM (Simultaneous Localization and Mapping), on the other hand, have big influence to photographing condition change of luminance, defocusing and so on. However, the relation between human attention model, Saliency map, and feature extraction methods in computer vision is not well discussed. In this paper, we propose a new saliency map and discuss the stability of keypoints extraction and their locations using BRISK by comparing other saliency maps

A Puzzle-Based Sequencing System for Logistics Items

The new demands of the current market including for space should be satisfied by designing modern material flow systems. Designing warehouses using effective material handling equipment significantly supports cost reduction and efficient space utilization. Sequencing of items is an important process that leads to enhanced logistics operations. Current approaches are not capable of fully fulfilling dynamic changes. Methods: In this paper, a puzzle-based sequencing system with a high density and highly efficient floor space utilization was successfully developed. Accordingly, two solving methods were investigated: game tree and pathfinding algorithms. A-star was chosen based on pathfinding algorithms in order to find the shortest solution of the puzzle in which the sequencing time was decreased. The pre-sorting strategy was proposed to overcome the unsolvable configuration issue that cannot be solved by the aforementioned methods. Moreover, the shape of the puzzle was considered. Results: Based on numerical calculations, we found that a square shape was better than a rectangle in terms of solution steps, and we confirmed the direct relationship between the aspect ratio and rectilinear distance, which directly affects the pre-sorting steps. Conclusion: Our results prove that the puzzle-based sequencing system should be highly preferred for effective floor space utilization compared to the current systems

Measurements of Total Neutron Cross Sections of C, Fe, Pb, O, Mo, Si, Zn, Ni, Sn, Ti and W at Energies 20-60 MeV

Measurements of total neutron cross sections of C, Fe, Pb, O, Mo, Si, Zn, Ni, Sn, Ti and W were made, using white neutrons from a thick Cu target bombarded by 65- and 75-MeV protons. The cross sections were obtained in the energy range 20-60 MeV. The obtained data agree well with others in the case where other data were already existing. The present work added several new data points for Ni, Mo, Sn, Zn, Ti and W, for which the number of existing data was not enough

Soil Compaction and Rolling Resistance Evaluation of a Locomotion System with an Adjustable Contact Patch for a Grape Transporting Robot

Soil compaction is a form of soil degradation which causes soil erosion, drainage difficulties, and loss of nutrients. To mitigate this issue, in agricultural farms several methods have been adopted. In this paper, the preliminary study of a locomotion system with adjustable contact patches is proposed. Aim is to reduce the compaction and optimize the rolling resistance of a grape transporting robot used in vineyard. A Finite Element Method (FEM) model supported by experimental results is developed to study the system

Towards building of an underwater robot monitoring fish appetite for feeding management: Development of sensors for measuring fish-generated underwater currents as indicator for feeding behavior

Predicting fish feeding behavior is crucial in improving marine aquaculture production. We are addressing this problem using a novel approach – measuring underwater currents generated by fish, especially at feeding times. In this paper, we present our development of a suite of sensors that will collect these measurements, as we investigate their relationship with fish behavior during feeding. We added we have further developed our sensor suite by adding another current sensor for calibrating the previously developed propeller sensors and tested them along a narrow river to examine the relationship of their measurements. While a strong linear relationship was observed between the measurements, it is difficult for the propeller sensors to measure currents accurately at slower currents. Experiment at the fish farm is still needed to determine if this constraint is acceptable in our application.ロボティクス・メカトロニクス講演会2021 (ROBOMECH2021), 2021年6月6日～8日, 大阪 (オンライン開催