二十数年前,"切削の7不思議というのがあって…"という指導教授の呪文に魅せられて(?),それならば,ととりついたのが運のつき.さしあたって切削現象の観察と"7不思議"を切削とは独立した試験により確認することとし,被削材の流動応力および摩擦特性式の検討を行った.このころ,"マトリクス法による構造力学の解法""マトリクス有限要素法"に接し,変形問題の汎用性のある数値解析法を知り,これを切削の解析に利用した.ところが,当時の計算機の能力は低く,これを有効に利用するため,切削現象の観察を通して,これに対応した種々の工夫を強いられた.この結果,現象の予測への道がひらかれ,以後工具摩耗・欠損の予測へと発展した.しかしいずれの場合も解析手法も重要であるが,明確な目的意識と現象を注意深く観察し,疑問と好奇心を持ち理論的に積み上げることがより重要であることを知らされた.
最近の相次ぐ新素材・新工具材の開発,それらの切削技術にしても,さしあたり必要な被削性・切削性試験を行うことは仕方がないにしても,先入観にとらわれることなく,常に疑問と好奇心を持って現象を注視する必要があろう.

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加工機器の研究とその手法について,最近の10年間を振り返り,筆者の独断で今後を展望してみた.いずれにせよ,わが国が工業立国として運命づけられ,モノ作りによって付加価値の創造をせざるを得ない限り,加工機器高度化のための研究開発は,避けて通ることのできない命題であると考えられる.次世代を担う若い研究者の方々に期待したい.

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フレキシブル生産に関する技術は,日進月歩の勢いで発展しつつあり,新しいシステム概念の提案,萌芽的研究,実用化研究,更には既存技術の改良が活発に進められている.その状況は,「FMSを主体とする第一段階の発展で蓄えた技術的及び人的資源を基にCIMを主体とする第二段階の発展をあるレベルまで達成し,現在は更なる次段階への挑戦を開始しつつある」とまとめられるであろう.そして,関連する技術の高度化に伴い,新しい概念を包含するシステムの提案が,例えば"Lean manufacturing"や"Agile manufacturing"のように,活発化している.その一方,「物作りにおける人間の役割」の重要性が世界各地域の文化や地政学,あるいは民族性や国民性とも深く関連して再認識され,異学術・技術領域との融合を考慮した,例えば"Cultural difference-based manufacturing"のような,システム概念も提案されている.これらは多様化,変動化,あるいは差別化しつつある生産要求への適応を図るためのもので,フレキシブル生産の定義,システム概念や構成等の多様化を招いている.
ところで,フレキシブル生産にかかわる技術の幅広さと深さを考えると,そのすべてを限られた紙数で述べることはむずかしいので,ここでは最近の代表的な研究課題,関連する研究に対する筆者の経験や感想等を述べることにしたい.

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最近,論文の書き方がよくわからないという声を耳にすることが多くなった.また,文献の引用が十分でないとの指摘を受けることも多い.そこで,「研究の方法」の特集を機会に,研究成果をまとめて論文として投稿する際に考慮しなければならないキーポイントについて,大学,研究所,企業の会員が現在学生等を指導している経験をもとにまとめることにした.

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B2-スプライソに基づく新しい3次のC²補間曲線を提案し,理論的に解析し,実例によってその有効性を確かめた.次はその特長である.
(1)従来のユニフォーム3次のB-スプライン補間曲線やKai・ChingChuのB2-スプライン補間曲線を一部として含むように曲線の局所性を,大域から局所へ,またその逆にと系統的に自由に制御できる.特に後者は本方法の顕著な成果であって,試行錯誤的にゴールを目指す形状設計過程において,特に最終段階で必要となる微妙な修正・制御を容易にする.
(2)変分問題や連立方程式を解くことなく,同等の結果を手軽に得ることができる.結果,全通過点がそろっていなくても曲線分ごとに次々と生成処理可能である.(3)ユニフォーム3次のB-スプラインに埋め込まれているので,表現形式は従来法と一貫性が保たれる.従って,B-スプラインやBézier曲線に関する周知の知識や技術も活用できる.
本方法を曲面式に展開するのは容易である.ノンユニフォームな節点列や一般の境界条件を含む補間問題にも,本方法の基本的な考え方は適用できる.まず,従来どおり補間に関連する連立方程式を解いてB-スプラインの制御点を求め,次に,3章で述べたように,関係のない遠い通過点の影響を落とした重心結合によって内部制御点を決めてゆけばよい.

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A method is proposed for planning motion path of manipulators avoiding collisions with obstacles. Though configuration space (or c-space) of manipulator is widely used for planning collision-free path of manipulators, it does not respond adequately to the geometric configuration of the collision, which brings non-uniform precision of the path and increase of its calculation time. To resolve this problem, firstly, an approach is adopted to separate global path planning which generates candidate paths in the c-space of manipulator, and local path planning which generates local paths avoiding the collision. Secondly, a method for planning the local path is proposed ; It generates a path keeping contact with obstacle surface by utilizing local configuration space, called cc-space, which represents the geometric configuration composed from the link of manipulator and the face of obstacle in contact. Based on this strategy, a computer program is developed and a path is generated successfully for PUMA type manipulator using the program.

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In order to make use of 5-axis control machining centers, the post-processor plays an important role, which converts collision-free CL data, generated by the main-processor, to actual NC data. The difficulty of developing the post-processor lies in the diversity of the structure of 5-axis control machining centers. The structure of 5-axis control machining centers can be classified into three types, that is, table-tilting type, spindle-tilting type and table/ spindle-tilting type. The study especially deals with the development of the post-processor concerning spindletilting type and table/spindle-tilting type 5-axis control machining centers, taking account of linearization, feed rate control and spindle rotation control. The validity of the post-processor developed in the study is experimentally confirmed.

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The Clothoid is a curve which has linearly changing curvature in relation to the length of the curve. By choosing the curve as the interpolating curve between freely given 2-dimensional point series, we can obtain a smooth free curve. In this report a practical method of Clothoidal interpolation, called "tangent method", is mentioned. The algorithm of the method is derived and some examples are shown.

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Drive units for robots and other automatic machines are generally composed of a motor and a reducing gear. Such units with inertia load show vibrational response to the reference change as well as to the load variation. In order to improve response speed and accuracy of the machines, these vibrations have to be suppressed. Many control methods successfully deal with the problem, but most of them are difficult to be practically realised or have a disadvantage of a needed high degree of knowledge for the controller design. An aim of the present research is a design of a simple but effective method for a vibration suppression. In this purpose a disturbance rejection control is used for motor and thus a dynamically decoupled motor and load system is obtained. The decoupling enables a simple design of a feedback loop for the vibration suppression. This paper discusses about the design of the feedback loop and its effect on the system's transient response.

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A robot machining system for industrial art objects has been developed. The objective of the system is both to make good use of technical skill of artist or artisan, and to realize the automation of machining of industrial art objects. The developed system is composed of three units: (i) input unit to record the machining data of artist or artisan directly, or to measure the model of an industrial art object; (ii) data processing unit to generate and modify model from the input data, and to transform model data into machining data; (iii) machining unit to machine industrial art objects according to obtained machining data. In this paper, the general philosophy about the system is given, and the construction of developed system, design policy and functions of each unit are described. An example of machining experiments is given to show the practical availability of the system.

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A study is presented of measurement for flatness by fitting partial shape deviations to large discrete flatness deviations calcurated by two-dimentional least square serial point method. In this paper, two methods are proposed. One is the method that uses the optical interferometer as the measuring head, and is applied with 2 DLS 3 PM. The other is the method which uses four displacement sensors as the measuring head, and is applied with 2 DLS 2 PM. The following fact is revealed by the experiment. The results of measurement by these two methods corresponded with accuracy of 0.05 μm (2σ). The accuracy is achieved to 1/20 movement errors of X-Y table used in this experiment.

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本研究では,新たな小型ロボットシステムを提案し,このシステムに適した自走式小型ロボットを構築した.この小型ロボットについて行った項目を以下に示す.
(1)自走式小型ロボットとして,駆動源をPM型リニアモータ方式とした新たな歩行型ロボットを提案した.また,水平面から90℃の垂直面での駆動を可能とするため,ロボットの"足"には小型電磁石を設けた.
(2)軽量化,小型化に重点をおき,実際に製作したロボットの寸法は,長さ16mm×幅27 mm×高さ12mm,重量は11.4gである.
(3)製作したロボットの定常状態における数学的動作モデルを提案した.
(4)ロボットを用いた実際の動作検定テストにより,この動作モデルの確認補正を行った.
(5)ロボットの位置制御におけるコマンドと動作に関する関係式には,この数学的動作モデルを用いることが可能となった.
今後は,この自走式小型ロボットの位置計測方式,位置制御方式の研究を推進し,新たな小型ロボット位置制御システムの構築を行う.将来的には,この小型ロボットシステムを複数用いた協調制御型小型ロボット群を提案する.

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This paper presents a new software datum method for roundness measurement, which is called the mixed method. In this method, 2-point displacement and a tangent angle of either point are simultaneously measured using 2 probes. A differential operation of them cancels the vibrational eccentric motions due to the rotational error and a deconvoluting operation of the differential data gives the correct roundness. In this paper, the mixed method is compared with the 3-point method, the traditional method of roundness measurement, by analyzing their transfer functions, resolutions and sensitivities to some factors of errors, such as the drift, positioning error, etc. Differing from the 3-point method, the mixed method can measure high frequency components regardless of the probe distance. The mixed method can also improve its resolution in the whole frequency domain by widening the probe distance. The effectiveness and limitations of the mixed method for roundness measurement have been verified by simulations and some important information for the sensor-design of roundness measurement have been gotten by theoretical analyses.

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今回,0.543μm He-Neレーザ,0.633μm He-Neレーザ及び1.06μm YAGレーザを光源とした,直線計を構成することによって,レーザビームのゆらぎ(ダンシング)は波長によって異なり,波長が長いとゆらぎが小さくなることが分かった.最終的には0.543μmと1.06μmの波長によって20m程度の距離で角度で約1.3×10^-6rad(0.27'')の測定精度が実現され,また補正率は約87%であることが分かった.

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For the on-machine roughness measurement it is desirable that the sensor is not easily affected by circumferential noise and datum errors due to the scanning motion. An optical stylus with an optical skid made by a new design concept is proposed to satisfy these necessities. In the developed sensor, a set of an optical source and an adjusting lens is added simply to the optical system of the usual critical angle type optical stylus. The optical beam from the added source is arranged to make another diplacement-sensitive range which is known as the wide range in the stylus of this type. The spot at the wide range is so large that it can smooth the profile of high spatial frequency components to serve for the optical skid. Influence of the thermal drift and other circumferential noises in the optical stylus is reduced to about 1/10 in the difference between the stylus and the skid. Profiles of ground surfaces are smoothed to almost flat planes in the output of the optical skid. Thus the developed sensor is confirmed to be very promising for the application to roughness measurements under on-machine or in-process conditions.

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This paper describes the development of the electromagnetic force sensor which can be used to measure both the displacement of its probe end from the measured surface and the normal direction of the surface. The inclination of the sensor axis from the normal direction can be obtained by measuring the three components of the magnetic attraction force which is applied to the magnet at the end of the probe, based on the fact that the force is perpendicular to the surface. In the preceding report, one of the authors proposed a magnetic force sensor with a permanent magnet. In this case, however, the diameter of the magnet should be large enough to get a sufficient force. Therefore, there are some problems as follows: (1) It is difficult to measure intricate configurations of the surface because of collision of the magliet to the surface. (2) The error of measurement is large at a point where the radius of curvature is small. (3) The weight of the magnet affects the measurement of the magnetic force. In the present work, the permanent magnet is replaced by an electromagnet, and the probe end is made sharp. Moreover, it is found that the preciseness of measurement can be improved by comparing the sensor outputs when the coil current is switched on and off, because the influence of the self-weight of the probe and the drift noise can be eliminated.

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Micro-cracks were mechanically induced in the CVD coating layers on a cemented carbide tool. With decreasing mean value of distance between cracks from 200 μm to 20 μm, tensile residual stress in the coating decreased from 0.55 GPa to 0.05 GPa, the initiation time of thermal fatigue cracks in face milling became longer, and the chipping resistance in interrupted cutting tripled. It seems that the improvement of tool performance is closely related to the relief of tensile residual stress in the coating.

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市販のラッピング装置を改良したポリシング盤を用い,Al₂O₃砥粒によってポリシングした磁気ディスク基板表面をWYKO,TalystepおよびNanoScopeIII等の高精度表面形状測定器で調べた.そして,除去機構を含め,数nmオーダの高平滑面形成の可能性を検討した.また,ポリシング特性に及ぼすポリシャの種類の影響を調べた.その結果は,以下のようである.
(1)Al₂O₃砥粒による数nmオーダの高平滑面形成ポリシングは可能で,その除去機構は,砥粒表面上の非常に微小な切れ刃による切削機構である.
(2)切れ刃の切削で形成される極微小面粗さは,全ポリシング過程を通じて,ほぼ一定である.また,除去速度も一定である.
(3)微小うねりは,除去厚さとともに,表面粗さとは独立的に,比較的徐々に平滑化され,ある除去厚さ以上になると,ほぼ一定の終末微小うねりになる.
(4)ポリシャ硬度を高くすると除去速度は高くなるが,終末微小うねりは大きくなる傾向を示す.

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To supply low-cost and high-precision ground gears, the CNC gear form-grinding machine with the truing attachment was developed. The grinding machine can finish spur and helical gears with an arbitrary profile and with a three-dimensionally modified tooth surface by using the supporting software developed at the same time. The structure of the grinding machine was determined so that positioning errors between the grinding wheel and work gear do not affect profile errors of ground gears, and that number of control axes becomes as small as possible. The grinding wheel is trued accurately on the machine by a single-point diamond dresser, of which the direction is controlled corresponding to the normal direction of the grinding-wheel profile. The accuracy of the gears finished on the grinding machine were better than 0 class of JIS and the surface roughness of the ground gears were lower than 1 μmR_max.

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Amorphous silicon/amorphous silicon carbide (a-Si/a-SiC) multilayer films are prepared by a dual rf magnetron sputtering method. The multilayer structure is confirmed by a depth profile of Auger electron spectroscopy (AES). Difference in the etch rate of amorphous silicon and amorphous silicon carbide in a mixture of HF, HNO₃ and CH₃COOH creates series of concentric steps in multilayer films, that show up clearly in the observation by an optical microscope. Furthermore, a small angle X-ray diffraction is carried out in order to be clarified the periodic structure. In the [a-Si (14.1 nm)/ a-SiC(7.5 nm)]₃₀ film with its superstructure period Λ =21.6 nm, from 1st to 23rd Bragg reflections caused by the regular periodicity can be observed. The diffraction profile has been well explained by a l-dimensional step model, which takes into account a random distribution of the superstructure period, varying according to a Gaussian distribution with the width ΔΛ/Λ =0.3 % (ΔΛ =0.064 nm).

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Grit sprinkling is important for the effective working process of a product with a diamond wheel. However, to date this working process is still carried out manually. Hence, development of a mechanical method is expected. In the present paper, sprinkling method utilizing a jet issuing from a nozzle is proposed and studied. Influences of diameter of diamond grits, jet velocity at the nozzle exit, depth of liquid in an electrodepositing bath and the distance between a nozzle and wall of a bath on the grit distribution are experimentally investigated. Dimensionless variables determining the mean position and standard deviation of the distribution are obtained by a method of dimensional analysis, and the empirical formulas for these values are presented. The uniformity of grit distribution on a nozzle sprinkle method are examined, and superiority of this method with the uniformity of distribution is confirmed.

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This paper deals with the ultrasonic screw vibration tapping for natural rubber. For the machining of elastic material such as natural rubber, it is necessary to heighten apparent rigidity of work material by decreasing the cutting torque by means of ultrasonic vibration. The following results were obtained. Female screw formed by ultrasonic vibration tapping with kerosene showed good geometry, especially in the case of rake angle 20°. Chip formation was mainly ribbon type for vibration tapping and powder type for conventional tapping. Cutting torque in vibration tapping was below half of that in conventional tapping and the value was about 30 Nmm. For very flexible natural rubber of the hardness 50 IRHD, female screw can be obtained with liquid nitrogen cooling by conventional tapping.

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