Robust position control of ultrasonic motor using VSS observer

Intrinsic properties of ultrasonic motor (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, when load torque is applied, dead-zone occurs in control input. Therefore, sliding mode controller, which is a nonlinear controller, is adopted for ultrasonic motor. The state quantities, such as acceleration, speed, and position are needed to apply the sliding mode controller for position control. However, rotary encoder causes quantization errors in the speed information. This paper presents a robust position control method for ultrasonic motor by using Variable Structure System(VSS) observer. The state variables for sliding mode controller are estimated by the VSS observer. Besides, a small, low cost, and good response sliding mode controller is designed in this paper by using a micro computer that is essential in embedded system for the developments of industrial equipments. The effectiveness of the proposed method is verified by experimental results

Frequency Control by Decentralized Controllable Heating Loads with H∞ controller

Many isolated small power systems are powered by diesel generators, which results in greater operating costs than interconnected large grids. It is therefore desirable to integrate renewable energy sources such as wind power into these small grids. However, due to the fluctuating power generation from renewable energy sources, frequency deviations of power systems become problematic. Distributed intelligent load control can be used to significantly increase renewable energy penetration and cut diesel fuel consumption. This paper presents a methodology for grid frequency control by electric water heaters as controllable loads. This system consists of diesel generator, wind farm, and loads. By applying a power consumption controller adopted from H∞control theory, grid frequency deviation is maintained around rated value. In order to verify the effectiveness of the proposed system, MATLAB/Simulink is used for simulations

How do socio-ecological factors shape culture? Understanding the process of micro-macro interactions

Socio-ecological environments produce certain psychological functions. that are adaptive for survival in each environment. Past evidence suggests that interdependence-related psychological features are prevalent in East Asian cultures partly due to the history of ‘rice-crop farming’ (versus herding) in those areas. However, it is unclear how and why certain functional behaviors required by the socio-ecological environment are sublimated to become cultural values, which are then transmitted and shared among people. In this paper, we conceptually review the works examining various macro sharing processes for cultural values, and focus on the use of multilevel analysis in elucidating the effect of both macro and individual level factors. Uchida et al.’s study (2019) suggests that collective activities at the macro level (community-level), which is required by a certain socio-ecological environment, promote interdependence not only among farmers but also non-farmers. The multilevel processes of how psychological characteristics are construed by macro factors will be discussed

Robust position control of ultrasonic motor considering dead-zone

Intrinsic properties of ultrasonic motor (high torque for low speed, high static torque, compact in size, etc.) offer great advantages for industrial applications. However, when load torque is applied, dead-zone occurs in the control input. Therefore, a nonlinear controller, which considers dead-zone, is adopted for ultrasonic motor. The state quantities, such as acceleration, speed, and position are needed to apply the nonlinear controller for position control. However, rotary encoder causes quantization errors in the speed information. This paper presents a robust position control method for ultrasonic motor considering dead-zone. The state variables for nonlinear controller are estimated by a Variable Structure System (VSS) observer. Besides, a small, low cost, and good response nonlinear controller is designed by using a micro computer that is essential in embedded system for the developments of industrial equipments. Effectiveness of the proposed method is verified by the experimental results

Antecedents and consequences of telework during the COVID-19 pandemic: A natural experiment in Japan

リモートワークの先行要因と結果 --コロナ禍での自然実験による検討--. 京都大学プレスリリース. 2024-03-19.Amidst the global COVID-19 pandemic, telework (remote work) has become a widespread practice adopted by companies worldwide. However, Japan has notably maintained a low rate of telework implementation, suggesting cultural factors hindering its adoption. This study aimed to elucidate the antecedents and consequences of teleworking in Japan. Leveraging the natural experiment created by the COVID-19 pandemic, we addressed two key questions: (1) What socio-psychological factors in Japanese workplaces were important for implementing telework in the first place? and (2) How did the implementation of telework subsequently influence socio-psychological factors in these workplaces? Employees from various Japanese companies completed three waves of an online survey before and during the pandemic. Results showed that telework was more likely to be implemented in organizations characterized by a meritocracy. Results also showed that the implementation of telework demonstrated no measurable negative effects but instead increased levels of independence, organizational commitment, and perceived hierarchy mutability

Venture into Cross-Cultural Psychology

A peer-reviewed book based on presentations at the XXIII Congress of the International Association for Cross-Cultural Psychology, 2016, Nagoya, Japan. (c) 2018, International Association for Cross-Cultural Psychologyhttps://scholarworks.gvsu.edu/iaccp_proceedings/1001/thumbnail.jp

Improving bonding strength by non-thermal atmospheric pressure plasma-assisted technology for A5052/PEEK direct joining

The direct bonding of A5052 aluminum (Al) alloy to the engineering polymer poly(ether ether ketone) (PEEK) using an atmospheric pressure plasma-assisted process was demonstrated. The effect of plasma irradiation on the bonding surface of metal resin on the bonding strength following thermal press fitting method was investigated. Specimens bonded by plasma irradiation on the PEEK surface only showed a high tensile shear stress of 15.5 MPa. With increasing plasma irradiation time, the bond strength of the samples bonded to the PEEK surface by plasma irradiation increased. The increase in the bond strength between metals and polymers following direct bonding is caused by the addition of oxygen functional groups on the polymer. In contrast, specimens in which only the Al was exposed to the plasma showed a decrease in bond strength compared with unirradiated samples. This reduction in bond strength is attributed to the forming magnesium oxide, which forms in the early stages of participation due to plasma irradiation.The version of record of this article, first published in International Journal of Advanced Manufacturing Technology, is available online at Publisher’s website: https://doi.org/10.1007/s00170-023-12747-

Influence of pre-treatment using non-thermal atmospheric pressure plasma jet on aluminum alloy A1050 to PEEK direct joining with hot-pressing process

The version of record of this article, first published in International Journal of Advanced Manufacturing Technology, is available online at Publisher’s website: https://doi.org/10.1007/s00170-023-12827-7.Aluminum alloy A1050 to polyetheretherketone (PEEK) direct joining with hot-pressing process via pre-treatment using non-thermal atmospheric pressure plasma jet has been performed. The effect of plasma irradiation on the tensile shear strength of A1050-PEEK direct bonded specimens joined by a combination of hot-pressing process and pre-plasma treatment using non-thermal atmospheric pressure plasma jet was investigated. A1050-PEEK bonded samples with plasma-treated PEEK only showed high tensile shear stress of 13.4 MPa. This increase in tensile shear strength is attributed to the addition of oxygen functional groups on the surface of the PEEK by reactive oxygen species produced by the plasma jet