著者

野口 晋 西田 勇 佐藤 隆太 白瀬 敬一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00254-17-00254, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

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It is known that the cutting force excites the structural vibration of machine tool. In addition, cutting force acts on feed and spindle drive system as a force disturbance, and feed speed and spindle speed are changed. As the results, cutting force is also changed because the depth of cut and cutting speed are changed due to the machine vibration, feed and spindle speed changes. The purpose of this study is to analyze the coupled vibration between the machine tool behavior and the cutting force. In order to achieve the purpose, in this study, a coupled simulation method of the vibration of machine tool, the dynamic behaviors of feed and spindle drive systems and the cutting force is developed. Cutting force and machined surface geometry is simulated using the voxel simulator in which the workpieces is represented by voxels. Undeformed chip thickness can be calculated based on the relative position between the tool and workpieces, and the tool rotational angle at the each time step based on the voxel model. The cutting force is estimated based on the calculated undeformed chip thickness. The relative position between tool and workpiece at each time step is simulated by the feed drive system and machine tool structural models. The tool rotational angle is simulated by the spindle drive system model. The coupled simulation between the cutting force, structural vibration of machine tool and feed and spindle drive systems is carried out by applying the simulated cutting force and cutting torque as a disturbance to the feed and spindle drive systems and machine tool structure. Cutting tests and simulations are carried out with two kinds of radial depth of cut, 5 mm and 20 mm. It is confirmed that the machine tool dynamic behaviors due to the cutting force and torque which is also influenced by the machine tool behaviors can be simulated by the proposed method. It is also confirmed that the chatter vibration which is observed in case of the 20 mm depth of cut can be simulated by the proposed method.

著者

高橋 辰伍 板野 健太郎 中本 圭一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00249-17-00249, 2017 (Released:2017-12-25)

参考文献数

13

被引用文献数

1

---

Agile manufacturing that can rapidly machine advanced materials or creative shapes is expected as an important key to realize mass customization of industrial products. Most of high-value-added workpieces have three dimensional and complex shapes. Thus, the workpiece shape and stiffness vary greatly according to cutting procedure during a rough machining operation. The induced displacement of workpiece strongly affects machining accuracy and tool life. However, it is difficult to automatically determine the process planning in commercial CAM system because of a large number of combinations. Therefore, the process planning has been designed by skillful experts to achieve complex parts machining. In order to realize future high efficient machining, it is necessary to obtain these tacit knowledges and to formulate the implicit machining know-how owned by skillful experts. As the first step, a method is proposed to decide workpiece shapes during a rough machining operation to ensure the workpiece stiffness based on topology optimization in this study. Topology optimization that is known as one of the highly flexible structure optimization methods enables to deal with the target configuration and shape. By introducing changeable fixed design domain and discretized characteristic function, an optimization problem can be converted to a problem of material distribution. In this study, the topology optimization is applied to decide workpiece shapes during a rough machining operation. As a purpose of minimizing their mean compliance, the optimized workpiece shape is calculated depending on applied loads at each machining step. By using the calculated workpiece shapes, a case study of complex parts machining is conducted. From the result, it is confirmed that a rough machining operation of complex parts can be achieved according to the decided workpiece shapes.

著者

金子 和暉 西田 勇 佐藤 隆太 白瀬 敬一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00247-17-00247, 2017 (Released:2017-12-25)

参考文献数

9

被引用文献数

3

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In end milling, in order to improve machining efficiency and accuracy, instantaneous rigid force model is widely used to predict cutting force and improve cutting conditions. The instantaneous rigid force model is well known as the practically simple model to predict cutting force. However this model requires the six parameters called cutting coefficients which have to be determined by the experimental milling operation. So several experimental milling operations are needed before cutting force prediction. In this study, a new instantaneous rigid force model based on oblique cutting is proposed. In this force model, the end milling process is modeled using the oblique cutting model. Therefore, cutting force prediction can be realized using only the one parameter such as shear angle instead of the six parameters such as cutting coefficients required for a conventional instantaneous rigid force model. The shear angle can be determined from tangential milling force or milling torque. And this force model is easier to apply for practical cutting force prediction, because time and effort to determine the parameter(s) before cutting force prediction. The validation of this force model compared with the conventional force model is performed. As the result, cutting forces predicted by the proposed force model has good agreement with the measured cutting forces. Also, the proposed force model has good performance in a wide range of cutting conditions compared with the conventional force model.

著者

冨江 瑛彦 久慈 千栄子 赤塚 亮 佐々木 啓一 嶋田 慶太 水谷 正義 厨川 常元

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00169-17-00169, 2017 (Released:2017-12-25)

参考文献数

3

被引用文献数

1

---

Powder jet machining is one of blasting processes conducted under room temperature and atmospheric pressure. This process brings both deposition and removal process, and in this study, it refers to powder jet deposition (PJD) and abrasive jet machining (AJM). As an application of PJD, the authors have proposed an innovative dental treatment method with the hydroxyapatite (HA) fine particle. By this method, thick HA coating can be fabricated directly in the human oral cavity. In this study, the effect of the particle impact angle was investigated as a parameter that affects the machining phenomenon. The experiments showed that the machining phenomenon transited depending on the blasting angle. In the vertical blasting condition, PJD process was just observed. On the other hand, in the more acute blasting angle such as 45 deg. or 60 deg. both coating and removal process appeared at the same time and in the most acute angle of 30 deg. only removal process was detected. The TEM observations showed that the impact surface of the HA substrate deformed and the deformation depth increased as the blasting angle get more acute. The smoothed particle hydrodynamics (SPH) method was utilized for the analysis for the fracture behavior of the HA substrate. The result indicated that the decrease of the impact angle induced the increase of the strain and the temperature of the interface between the particle and the substrate. Thus it is concluded that the shear stress, which refers to the impact angle, induces the destruction of the substrate by the deformation and the brittle fracture due to the thermal stress.

著者

辻野 元大 古城 直道 山口 智実 廣岡 大祐 松田 茂敬 岩佐 康弘 寺内 俊太郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00161-17-00161, 2017 (Released:2017-12-25)

参考文献数

18

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Diamond cutting tools show severe wear in turning of steels. In previous paper, it was shown that carbides on ferrite phase, which were precipitated by carburization, suppressed the diamond tool wear. In this paper, detailed distribution of constituents of the carbides was analyzed by EDS (energy-dispersive X-ray spectroscopy). In addition, characteristics of each carbide such as occupancy, diameter, and degree of circularity were measured. Results indicate that those characteristics of the carbides influence suppression of the tool wear.

著者

道辻 洋平 石井 翔 長澤 研介 松本 陽 大野 寛之 佐藤 安弘 緒方 正剛 谷本 益久 岩本 厚 福島 知樹 品川 大輔

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00283-17-00283, 2017 (Released:2017-12-25)

参考文献数

15

被引用文献数

5

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It is important to secure running safety of railway vehicles against wheel-climb derailment accidents. The safety is often discussed according to the value of derailment coefficients for the leading outside wheel of a railway bogie running on sharp curves. Therefore, the detailed force induced mechanism which influences the value of derailment coefficients should be clarified. One of the most dominant factors affecting the value of derailment coefficients is magnitudes of the coefficient of friction (COF) between wheel and rail. Since the gauge corner of the outer rail and the top of the inner rail are lubricated at some sharp curves, COF of wheels of a bogie are different from each other and show complicated variation. In this study, the effect of lubrication for the running safety of the railway bogie is investigated while considering the detailed force induced mechanism of the derailment coefficient increase utilizing both multibody dynamics simulations and experiments. Experiments and simulations are conducted with a roller-rig test equipment under various conditions of wheel/rail lubrication. In this research, a method to identify whether the bogie is in suitably lubricated condition in terms of running safety is discussed. The proposed method making use of the longitudinal force measurement with mono-link type axle supporting device is mentioned.

著者

吉澤 厚文 大場 恭子 北村 正晴

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00263-17-00263, 2017 (Released:2017-12-25)

参考文献数

31

被引用文献数

2

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This research aims to develop capability of on-site staffs that can respond to beyond ‟design basis accident (DBA)” in the sophisticated socio-technical system, in which ensuring safety has been more complicated. Fukushima Daiichi nuclear accident is therefore considered as the actual case of “beyond DBA”. The authors focused on the actions to prevent the accident progression undertaken by on-site staffs, which were hardly evaluated in existing accident analyses and reports. With reference to the concept of resilience engineering, “Responding” of the four cornerstones was particularly analyzed. Based on the precedent studies, causal factors of modeling “Responding” where pointed out the importance of “Attitude” that is a new lesson learned from on-site response at the accident. In addition, new lessons learned on improvement of skills indicated the limit of the concept of risk removal type safety as a safety goal that human is defined as “a safety hazard element”. This led the necessity of the success expansion type of safety as a new safety goal that human is defined as “a resource necessary for system flexibility and resilience”. Focusing on “Responding” on-site enabled to deduce core competence by extracting causal factors. Thus, new lessons learned successfully derived introduced for human resource development of the next generation to lead technologies in the society.

著者

酒井 忍 北出 侑也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00225-17-00225, 2017 (Released:2017-12-25)

参考文献数

17

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Ball shooting machine (pitching machine) is used for practicing ball sports, and it is widely prevalent. However, there are few pitching machines that can throw a ball with a gyro spin, such as a football or rifle bullet, in which the axis of the ball spins in the same direction as the ball travels. In this study, a new ball shooting machine, which can throw in the ball in a wide range of speeds and all pitch types (no, top, down, side and gyro spin balls) was invented by introducing a launch mechanism using four rollers (two launch and two gyro rollers). The shooting machine is able to arbitrarily change the rotational speed of the four rollers and the crossing angle of both gyro rollers. Shooting tests were conducted using the prototype shooting machine to confirm the ability of its performance. From the experiment results, the prototype machine had a maximum ball speed of 42.5 m/s, a spin rate of exceeding 5000 rpm, and a ball of any pitch type could also be shot. In addition, the position accuracy (shot accuracy) at the targeted fall position in the opponent's court was high because the gyro spin and other pitch types (no, top and side spins) were less than 140 mm and 40 mm (the diameter of one table tennis ball), respectively. The prototype machine had the necessary launching performance for table tennis practice of a college student level.

著者

荒木 大地 長田 拓也 中内 靖 川口 孝泰

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00210-17-00210, 2017 (Released:2017-12-25)

参考文献数

33

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Falling from the bed is a common type of accident and places considerable burdens on patients and nurses. Structural and risk factors for the occurrence of falls have been identified, but fall prevention remains extremely difficult due to the patient’s physical, mental, and social factors and treatment environment. Most fall prevention measures involve ascertaining the risk of falls through the use of risk assessment score sheets and bed sensors, but there are few measures for active fall prediction. To develop a method for fall prediction, we applied area trajectory analysis and spectrum analysis to the characteristics of center-of-gravity variation in certain movements. We used these analysis methods and applied Support Vector Machine (SVM) that is one of the methods of machine learning. Experiments were performed with 5 healthy male and female. Each participant performed 3 movements, Reach out, Bed rail and Active, on a bed for 1 min each, during which time-series data on center-of-gravity variation were recorded. In the micro-average about unknown data, the Precision rate was 90.6%. To evaluate the movements respectively, Active were both higher in Precision rate and Recall rate. However in the Reach out has low Precision rate and that likely cause misinformation, in the Bed rail has low Recall rate and that likely cause overlook. The results of this study suggest the possibility of fall prediction through center-of-gravity analysis. In the next step about this study, need to explore the discriminate about static posture and improvement in accuracy by increasing the learning data.

著者

嶋脇 聡 吉田 和樹 中林 正隆

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00063-17-00063, 2017 (Released:2017-12-25)

参考文献数

36

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Arterial endothelial function is known as a factor that correlates with progression of arteriosclerosis. This is measured by flowmediated dilatation (FMD) testing. This test is performed by measuring the brachial artery diameter with an ultrasound system or by measuring digital pulse volumes. Technical and cost-related problems have been pointed out for both methods. We came up with an idea to apply the near-infrared light-based vascular visualization to the measurement of changes in vessel diameter. So, at first, we investigated whether the FMD reaction can be detected with near-infrared transmission images. Next, we derived the estimated values that is considered to correspond to the FMD reaction from the vascular image change. We aimed to determine if these estimated values correlate with brachial-ankle pulse wave velocity (baPWV), which is related to arteriosclerosis. In 50 adult males varying in age, the right upper arm was compressed with a cuff at 200 mmHg for 5 min to cause the FMD reaction after the cuff release. In a 11-min period including time points before and after the cuff compression, near-infrared (wavelength: 850 nm) transmission images near the bilateral finger joints were taken with a CCD camera. The mean brightness was calculated from the images. While no major temporal changes in mean brightness were observed before cuff release, the mean brightness of the hyperemic finger sharply decreased after cuff release. This result suggested that the FMD reaction can be detected with near-infrared transmission images. When the brightness decrease ratio (BDR1) before and after cuff release were compared among age groups, BDR1 at age 50 over years group was significantly smaller than that at age 20-29 years group (p<0.05). BDR1 showed a significant negative correlation with baPWV (R=0.34). This measurement method is considered to have a possibility of estimating FMD reaction and arterial endothelial function.

著者

上田 隆司 平井 佑樹 社本 英二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00344-17-00344, 2017 (Released:2017-12-25)

参考文献数

12

被引用文献数

3

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In high speed turning, six kinds of materials, namely, Ti-6Al-4V, Inconel718, SUS304, S50C, Copper and Aluminum are machined with a ceramic cutting tool in order to investigate the influence of the cutting speed on the temperature of the cutting tool experimentally. The cutting temperature is measured by the two-color pyrometer with an optical fiber which is developed by the author. In cutting of Ti-6Al-4V and Inconel718 with Al2O3 ceramic tool, the cutting temperature increases with the increase of cutting speed and approaches to the melting points of the workpiece materials. The thermal conductivities of these difficult-to-cut materials are small, and Al2O3 ceramic has a small thermal conductivity and maintains a high strength even at the temperature of about 1000°C. In the cases of Copper and Aluminum, their thermal conductivities are much larger than those of Ti-6Al-4V and Inconel718, so that the cutting temperature increases so slowly with the increase of cutting speed that it is difficult to approach to the melting points of the workpiece materials.

著者

今 智彦 本田 知己 中村 由美子 高東 智佳子

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00285-17-00285, 2017 (Released:2017-12-25)

参考文献数

15

被引用文献数

1

---

Wear of sliding surfaces in machinery is one of the major causes of mechanical failure. Thus, detecting wear on sliding surfaces is very important for preventing mechanical failure. Current diagnosis methods for detecting wear particles such as a spectrometry oil analysis program, particle count method and ferrography method are very useful for it. However, these methods need high cost, expertise and long time for the analysis. Moreover, the particle count method can only measure the size and the number of particles and it cannot indicate whether the lubricating oil is degraded by oxidation or solid particles. Therefore, the diagnosis method which can evaluate degradation cause and level of lubricating oil is required for effective maintenance. The authors have developed a new diagnostic method for lubricating oils by the colorimetric analysis of membrane patches. In the previous study, we reported that there is a good correlation between membrane patch color and contamination in lubricating oil. From the results of our previous study, it is possible to diagnose wear on sliding surfaces by using membrane patch color. The purpose of this study is to develop new wear monitoring method of sliding surface in machinery by using membrane patch color. First, we conducted filtration tests to investigate degradation causes of lubricating oil in actual machinery. The results showed that they are classified into solid particles and/or oxidation products. Secondly, we prepared oil samples which were artificially degraded by solid particles and/or oil oxidation products based on the filtration test, and we conducted wear tests in the degraded oils by using block-on-ring tester. The results presented that it is important to detect not only the number of particles but types of particles for the monitoring of wear on sliding surfaces. Finally, we investigated the relation between ISO cleanliness code and membrane patch color and we proposed a new parameter Ic using the ISO code. As a result, it is shown that it is possible to detect wear on sliding surfaces easily using Ic and membrane patch color.

著者

五百井 清 大坪 義一 辻合 真也

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00346-17-00346, 2017 (Released:2017-12-25)

参考文献数

19

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This paper analyzes metal-mold polishing by human hands. The metal-mold polishing generally requires long experiences about polishing works. Although experienced persons have many excellent skills, it is a little difficult to evidently teach them to beginners in words because most skills are considered to depend on their physical and intuitive memories. Thus we attempt to bring out the characteristic skills about metal-mold polishing by human hands. This paper mainly discusses the difference of polishing skills between experienced persons and beginners. First, a new data acquisition tool is developed to obtain polishing data, which is designed similar to old tools used by experienced persons. The tool basically consists of a small grasping spatula, a grindstone chip, a force sensor, and a 3D motion sensor. Second, basic data acquired from the developed tool are explained, and the estimation method about some kinds of data is proposed, which are not directly obtained from the sensors attached to the tool. Third, the characteristics between experienced persons and beginners are carefully compared from the view of the tool angle, the polishing velocity, the pressing force, and the mean power of polishing. Then, we focus on the phase trajectories between the polishing position and velocity, and the resistant forces appeared in forward and backward polishing. In order to understand the interesting phenomena about the phase trajectories and resistant forces, a simple dynamical model is newly assumed, and the model evidently explains the phenomena. Finally, the main results and future works are summarized.

著者

木村 佳史郎 釜道 紀浩

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00328-17-00328, 2017 (Released:2017-12-25)

参考文献数

15

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An ionic polymer-metal composite (IPMC) actuator is an electric driven soft actuator. It is fabricated by chemically plating metal on both surface of an ion-exchange membrane. It is able to be activated by a simple driving circuit and low applied voltage (0.5-3 V). However, a precise control of the IPMC actuator is difficult because of individual difference and characteristics changes from environmental conditions. To solve this problem, we applied the stochastic ON/OFF controllers to the integrated IPMC actuator with parallel connections. The controller consists of a central controller and distributed controllers. The central controller broadcasts a control signal as an error signal to distributed controllers uniformly. The distributed controllers switch the ON/OFF states based on the broadcasted signal stochastically. The central controller dose not measure the states of each IPMC actuator, and the control signals is calculated by using the output signal of the integrated actuator and reference signal. The validity of the applied methods was investigated through numerical simulations and experiments of displacement control. The proposed method was demonstrated to be useful as in the case that some actuator elements fail.

著者

金田 一輝 森田 寿郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00297-17-00297, 2017 (Released:2017-12-25)

参考文献数

7

被引用文献数

3

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This study aims at realization of passively adjustment of compensation force generated by Mechanical Gravity Canceller (MGC). If an object attached to MGC is changed, it needs to adjust spring force for accurate balance. In the previous studies, self-tuning load compensable mechanism for MGC is developed. The mechanism can compensate torque of both manipulator's weight and load by using springs. However, the mechanism has a weak point that is necessary to rehang the spring as the load changes. More energy is required to rehang the spring than to lift the object which isn't compensated. For a solution of this problem, a passive adjustment mechanism is developed. The passive adjustment mechanism has two springs. One of the springs (spring 1) compensate its weight and another spring (spring 2) compensate load. Then spring 2 weigh load by changing displacement and the displacement change the compensation force of spring 2 passively. Therefore, the passive adjusting Mechanism can compensate its weight and arbitrary load completely. Moreover, to improve safety, the mechanism applies to an up-and-down system of the arbitrary load. The testing machine realizing proposed mechanism is 19 kg and can compensate from 0 kg to19 kg arbitrary load. Relative errors of compensation power of the machine are under 10 % and relative charged energy converges 10.5 % as increasing weight of load.

著者

杉山 将史 池田 啓祐 金田 翼 甲斐 義弘 富塚 誠義

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00279-17-00279, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

4

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When developing rehabilitation assist suits, safety consideration for patients is crucial. Computer-aided control techniques can improve their safety. However, when the computer breaks down, the assist suit may be dangerous for the user because of its unintentional motion. Therefore, assist suits with hardware-based safety devices are desired to guarantee safety even when the computers do not operate properly. In this paper, we present a new rehabilitation assist suit equipped with a velocity-based safety device and a torque limiter. The assist suit assists a patient's knee joint. The velocity-based safety device switches off the assist suit's motor if it detects an unexpected high joint angular velocity. The torque limiter cuts off the torque transmission if it detects an unexpected high joint torque. These safety devices will work even when the computer breaks down, because they consist of only passive mechanical components without actuators, controllers, or batteries. Firstly, we describe the features of the assist suit with the safety devices. Secondly, we introduce the structure of the assist suit. Thirdly, we explain the structure and mechanism of the velocity-based safety device. Fourthly, we show the prototype assist suit that we have developed. Finally, we present experimental results to verify the effectiveness of the velocity-based safety device installed on the developed assist suit.

著者

大平 峻 島田 明

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00276-17-00276, 2017 (Released:2017-12-25)

参考文献数

12

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This study proposes a movement control system based on model predictive control (MPC) with state expressed identity disturbance observer (DOB). The proposed controller removes tracking errors of control variables due to disturbance influences. The DOB estimates the motion state as well as the disturbance acted to controlled plant. This paper assumes two types of disturbances acted to control input and to control output. The input disturbance is a steady and the output disturbance is not always steady. The presented MPC system including the DOB is robust and it suppresses disturbances via the special design method. The feasibility of the MPC-based control system is conrmed in the situation under the input and output disturbances. Finally, the proposed method is evaluated via the simulation related to a cart traveling along a straight line.

著者

古性 裕之 毛利 宏

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00203-17-00203, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

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We propose curve contour detection algorithm for road white line detection based on Helmholtz principle. White line detection is widely used in driver support systems used mainly in highway or major arterial road. As the common road will be the target of operational area for autonomous vehicle, it is thought to be necessary to develop a new detection algorithm that can deal with various types of road. This paper proposes model-less algorithm that is constructed on a new edge feature inspired by Helmholtz principle through the analysis of the limit of Hough transform. This feature is basically same as Hough defined feature of edge count on the line except two remarkable points. The one is the restriction of count area and the other is the way of count which affords to detect curve line as well as straight line. Implementation by convolutional neural network is explained and the relation between tunable parameters and the detection performance as well as the processing time are discussed. Comparison between conventional methods such as Hough transform or machine learned contour detection algorithm BEL is explained for test image and images taken by on-board camera to show the superiority of proposed algorithm. We demonstrate that proposed algorithm that can apply to diverse road environments but is hardly affected by noise can be realized.

著者

上甲 康之 黒澤 真理 高橋 幸太郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00140-17-00140, 2017 (Released:2017-12-25)

参考文献数

5

被引用文献数

1

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This paper verifies the validity of the prediction model of clothes behavior by using random number. Outer tub of a front-loading washer-dryer is supported by the vibration isolation structure because the imbalance of clothes inside the drum causes vibration in dehydration. The imbalance beyond an acceptable level is modified by the dehydration control system to reduce the vibration. However, the modification of imbalance causes an extension of operation time. Therefore, it is important to estimate the numbers of modification in initial design stage in order to reduce vibration and operation time. In this study, dehydration simulator was proposed to estimate the numbers of modification using Monte Carlo approach. This simulator consists of three steps; the first step is to generate random numbers following the probability distribution of clothes behaviour obtained by experiment, the second step is to count the random numbers beyond threshold as the numbers of modification, and the third step is to repeat previous steps and to obtain the average number of modification. As a result, the maximum absolute difference of the average number of modification between experiment and prediction was 1.6 times. In addition, the relationship between the threshold and the average number of modification requires about 80 days to be obtained in experiment, but it is shown that the relationship was predicted within a day in proposal method. These results would provide the validity of the proposed approach.

著者

高見 創 嵯峨 信一

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.82, no.844, pp.16-00337, 2016 (Released:2016-12-25)

参考文献数

13

被引用文献数

1

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Brake squeals phenomena of the disc brake system for railroad cars were reproduced and were investigated in the test stands using a full-size brake rotor, a wheel, a floating caliper and a brake pad. Brake squeals of the disc-brake apparatus occurred at a low speed of 20 km/h or less, and the magnitude of brake squeals increased as the average braking force increases until it was saturated. Frequencies of the brake squeals exceeding the background noise of the test facility are 800 Hz, 2 kHz, 3.2 kHz, and 6.3 kHz. The largest squeal of 6.3 kHz was radiated from the leading side of the pad and the rotor, and coupled vibrations between the rotor and the pad were attributed to the self-excited vibration induced by the dry friction. To measure the vibrations of the rotating disc at the time of brake squeals, vibration measuring systems operating by wireless power supply were installed in the rotating axle. As a result, one-third octave band analysis of brake squeals at 6.3 kHz and at 3.2 kHz approximately coincides with the vibration of both the rotor and pad, and the coupled vibration tends to grow larger in the high friction coefficient range. Furthermore, these frequencies agree well with the natural frequency of the rotor examined using the scanning laser doppler vibrometer. The mode shapes and amplitude of rotor vibrations at the time of brake squeals are significantly affected by the number of bolts and their fastening positions to the wheel.