湿原用移動ロボットのための二重螺旋機構に関する研究

本論文では，環境調査を支援するロボット技術の開発を目的としており，湿原で螺旋進行機構について取り上げ，3次元モデルの設計，運動学と動力学解析，シミュレーション，動作性能解析を示した。今現在,世界では湿原の面積は年々減少する傾向にあり，湿原の保全や再生の一環として湿原の現地調査が行われている。 調査を効率的に行うために移動ロボットに対する要求がある。このような屋外・不整地での作業を目的としたロボットの移動機構として,クローラや車輪を採用しているものが一般的である。本研究で提案している螺旋移動機構は草の間を縫うように進むことで，草の抵抗を大きく受けず, 湿原の植物を傷つけることなく移動できる。本研究の最終目的は,湿原特有の丈長草地において，調査機材をロボットに積載し, 遠隔地であるいは自律で操作および計測等調査ができる移動機構を実現することである。本論文ではまず，二重螺旋推進機構の提案と設計最適化，全体の構成など動作過程について述べた。装置全体は大きく分けてプラットフォーム，マニピュレータ，螺旋駆動ユニット，螺旋の4つの部分で構成される。螺旋の持ち上げ等のマニピュレータには螺旋の上に立脚するためのものと螺旋の把持·駆動を行う螺旋駆動ユニットの二種類がある。ロボットの移動について，脚部が次の螺旋へ移動するとき，シリアルマニピュレータとして働く。また，ロボットのプラットフォームを移動させ，ロボットの重心を移動させるとき各脚は固定されており，パラレルマニピュレータとして働く。これらの座標系を確立し，運動解析を行った。次に，螺旋を保持し，回転させる機能が求められる駆動ユニットについて述べた。プーリーを利用した駆動ユニットを提案し，詳細設計と製作·組み立て，実験システムの運動学方程式の導出及び理論を明確にし，それに基づく，モーションキャプチャを用いた特性計測による実験データを解析した。駆動ユニットの動力学モデルの検討及び理論解析を行い，駆動装置と螺旋体を使って屋内および屋外において実験を行い,その結果を考察し，螺旋駆動に必要なトルクを算出するところまでを述べた。螺旋の把持·駆動等の動作を行う螺旋駆動ユニットにおけるマニピュレータは回転関節３つと直動関節1つで構成されるものとする。運動学と逆運動学を解析し，マニピュレータのワークスペースの検討と評価を行った。把持と駆動を行う駆動ユニットの動力学モデルをロボットシミュレータ(V-REP)により構築してシミュレーションを行った。その結果を考察し，駆動ユニットの動作性能を検討・評価した。This dissertation has been dedicated to the study, modelling, simulation and motion analysis on spiral mechanisms for robot moving on wetlands. Environmental problems related to wetlands have attracted strong concern around the world during past decades. Many kinds of mobile mechanisms have been developed to satisfy demands of environmental investigation of wetlands. However, few researchers have studied spiral propulsion mechanisms. Our previous work showed that the spiral was able to move forward between gaps of plants, giving only very slight damage to plants. It is introduced to carry measurement devices in wetlands when investigating the current state of wetlands. The structure and walking procedure of a proposed double spiral robot are derived. The bilateral symmetry robot consists of a platform, manipulators, and spirals. In the walking procedures, the manipulators work as serial structure with open kinematic chain and serially connected links, except one step in one walking circle. The kinematic analysis of the robot working as a serial mechanism is performed, in which the detailed structure, coordinate system, and parameters of this mechanism are given. Modeling and kinematic analysis are also addressed when the robot is working as a parallel mechanism. As the fundamental unit of spiral mechanisms, spiral driving unit should rotate spiral (without a center axle) in the expected direction in a stable attitude. Center axle drive method and circumference drive method have been introduced. To enhance the stability of spiral, a new drive method based on three U-shape pulleys is proposed. The structure and dynamic model are derived. To verify the driving units’ performance, experiments were performed based on a motion capture system. We also proposed a method to analyze the attitude angles, rotated angles and traveling displacements of the spiral. The kinematic relations between the driving unit and the spiral are established on the premise of the data from the motion capture system. Experimental results for driving units of two kinds of drive model are quantitatively analyzed, with emphasis on attitude stability, technical feasibility, and repeatability. To investigate the resistance between spiral and the stems of grass, in-door and field experiments are also performed under the conditions of cone-shape end parts mounted and un mounted respectively. A manipulator arm which consists of 3 revolute joints and 1 prismatic joint is proposed to satisfy requirements of driving unit for gripping and rotating spiral. The forward and inverse kinematic are fulfilled and the 3D model of the manipulator is established in an dynamic simulation software (V-REP). To verify the feasibility, the process of manipulator gripping spiral is simulated. As a result, the joint position and joint internal position error curves are significantly reduced.室蘭工業大学 (Muroran Institute of Technology)博士（工学

A Four-Legged Mobile Robot with Prismatic Joints on Spiral Footholds

This paper addresses a new design of a four-legged mobile robot with a double-spiral mobile architecture. The double-spiral mobile architecture has been proposed with the intention of use for environmental surveys in wetlands, where reed-like plants grow densely. It consists of two pairs of spirals and one mobile robot. Each pair of spirals plays the role of footholds for the mobile robot. By traveling at a higher place from the ground, the robot can avoid strong resistance force from the dense and hard-stemmed plants. In addition, the spirals intermediate between the robots and the muddy ground to avoid sinking. The proposed leg mechanism does not have any vertical movement. It contributes to energy saving in the robot. Also it provides the arbitrary motion of the body platform while the legs grip the spirals tightly. We derive the robot’s kinematics and statics and show the validity of the design mathematically.特集 : The Papers Presented at the Symposium on Mechanical Engineering, Industrial Engineering, and Robotics 2015 (MIER2015) held at Muroran, Hokkaido, Japan on 29 - 30 May 201

Development of a Spiral Propulsion Mechanism in Wetlands-Relation between Torque and Load

This paper addresses load properties of a spiral propulsion mechanism in wetlands. Recently, area of wetland has been decreasing due to farmland development and so on. The phenomenon is becoming one of the major environmental conservation concerns. The project of investigation of the current state and its degradation trend of the marshland has been started. The most significant challenges to the field surveys focus on the development of locomotion mechanism to carry measurement devices in wetland. One of the authors has proposed spiral propulsion mechanisms for movement in wetlands. Fundamental experiments have been performed in the bank of a river, where was covered with dried long-stem plants, and the traction properties of the spiral propulsion mechanism in wetlands is investigated. We have proposed a simple formula which describes the relation between torque, load and traction. The data of the experiment fit the formula well in range of less than a certain value of load.特集 : 「資源、新エネルギー、環境、防災研究国際セミナー

A Network Flow Algorithm for Solving Generalized Assignment Problem

The generalized assignment problem (GAP) is an open problem in which an integer k is given and one wants to assign k′ agents to kk′≤k jobs such that the sum of the corresponding cost is minimal. Unlike the traditional K-cardinality assignment problem, a job can be assigned to many, but different, agents and an agent may undertake several, but different, jobs in our problem. A network model with a special structure of GAP is given and an algorithm for GAP is proposed. Meanwhile, some important properties of the GAP are given. Numerical experiments are implemented, and the results indicate that the proposed algorithm can globally and efficiently optimize the GAP with a large range cost

The design of underwater tactile force sensor with differential pressure structure and backpropagation neural network calibration

The underwater tactile force measurement was prone to cross-sensitivity, causing the difficulty in distinguishing tactile force signal with the underwater complex environment of water pressure influence. For this problem, an underwater tactile force sensor whose sensing core was based on Microelectromechanical Systems (MEMS) was designed with differential pressure typed structure. The hollow hemispherical flexible contacts located at the upper and lower end, and the hollow cylindrical shell in the middle part composed the structure of the capsule-shaped sensor. The upper flexible contact could sense the compound signal composed of water pressure and tactile force, at the same time, the lower flexible contact could measure the water pressure information. The deformation signal of the upper and lower flexible contacts could be transformed to the force sensor core’s upper and lower surfaces with silicon oil filled in the inner hollow part of the sensor. The tactile force signal could be obtained with water pressure eliminated through vector superposition method under the influence of static pressure of water. The structure and manufacture technology were introduced, and the Backpropagation (BP) neural network data regression algorithm was designed for the cross sensitivity. The experiments are conducted to demonstrate the effectiveness of the differential pressure structure in eliminating the influence of water static pressure. The results indicated that the BP neural network data regression algorithm successfully produced real tactile force signals, which is highly beneficial for the intelligent operation of underwater dexterous hand. Additionally, the sensor has an accuracy of 5%