Ding-jian Huang, Li-gang Yao, Wen-jian Li and Jun Zhang
The purpose of this research is to achieve a novel magnetic nutation drive for an industry robotic wrist reducer.
Abstract
Purpose
The purpose of this research is to achieve a novel magnetic nutation drive for an industry robotic wrist reducer.
Design/methodology/approach
A novel magnetic nutation drive is proposed, and the structure and principle of the designed magnetic nutation drive are described in this study. Three-dimensional finite element analysis is used to compute the magnetic and torque of the magnetic nutation drive. Furthermore, a prototype of this novel magnetic nutation drive device is developed with 3D printing technology and tested to verify the feasibility of the proposed structure and principle.
Findings
The simulation and experimental results indicated that the proposed magnetic nutation drive device could meet the desired specifications, and that this novel magnetic nutation drive device successfully realized the non-contact transmission ratio of 105:1 required for a robotic wrist reducer.
Practical implications
This novel magnetic nutation drive is low-cost and easy to make and use, and which provides the non-contact transmission ratio of 105:1 required for a robotic wrist reducer.
Originality/value
For the first time, this research applies the permanent magnet drive technology to nutation drive and puts forward a new non-contact nutation drive mode. The novel drive mode can solve some problems of the traditional mechanical contact nutation drive, such as vibration, friction loss, mechanical fatigue and necessity of lubrication. The proposed non-contact nutation drive device can achieve a high reduction ratio with compact structure and can be suitable for industry application.
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Keywords
Kunling Zhang, Chunlai Chen, Jian Ding and Zhinan Zhang
The purpose of this paper is to evaluate the economic impacts of China’s hukou system and propose the possible direction for future reform.
Abstract
Purpose
The purpose of this paper is to evaluate the economic impacts of China’s hukou system and propose the possible direction for future reform.
Design/methodology/approach
The study develops a framework to incorporate the hukou system into the economic growth model. Using prefecture city-level panel data covering 241 cities over the period 2004–2016 and applying the fixed effects and instrumental variable regression techniques, the authors investigated empirically the impacts of the hukou system on city economic growth.
Findings
The study provides three main findings. First, the city sector conditionally benefits from labour mobility deregulation that allows migrants to work in cities. Second, the hukou system has different impacts on economic growth among cities with different sizes and administrative levels. Third, to offset the costs of providing exclusive public services to the migrants, the big or high-administrative-level cities can use their high-valued hukou to attract the high-skilled migrants, but the small- or low-administrative-level cities do not have this advantage.
Practical implications
This study suggests that the key for further hukou system reform is how to deal with the hukou–welfare binding relationship.
Originality/value
The authors developed a theoretical framework and conducted an empirical analysis on the direct relationship between the hukou system and economic growth to reveal the mechanism of how does the hukou system influence the city economic growth and answer the question of why is the hukou system reform so hard in China. The framework also sheds some lights on explaining the success and failure of the hukou system reforms in the past 40 years.
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Changlong Ye, Yingxin Sun, Suyang Yu, Jian Ding and Chunying Jiang
The mechanical properties between wheel and ground will affect the motion performance of wheeled omnidirectional mobile robot (OMR). MY3 wheel is an omnidirectional wheel. This…
Abstract
Purpose
The mechanical properties between wheel and ground will affect the motion performance of wheeled omnidirectional mobile robot (OMR). MY3 wheel is an omnidirectional wheel. This paper aims to analyze the contact mechanical characteristics between MY3 wheel and ground to improve the motion accuracy of an omnidirectional mobile platform with MY3 wheel (MY3-OMR).
Design/methodology/approach
This method takes MY3 wheel as the research objective. The normal and tangential contact mechanics model and rolling contact mechanics model of MY3 wheel are established by analyzing the structure of MY3 wheel, and thereby, the slip ratio of MY3 wheel in the process of motion is calculated. The kinematics model of MY3-OMR is optimized by taking the slip ratio as the optimization parameter that aims to improve motion accuracy of MY3-OMR.
Findings
The correctness of the mechanical analysis and the feasibility of the method are verified by the MY3-OMR prototype. Let MY3-OMR move along the set circular trajectory and square trajectory, and the error between the motion trajectory before and after optimization and the standard trajectory is obtained. It illustrates that the error in the square trajectory is reduced by 1.5%, and the circular trajectory error is reduced by 2%; therefore, the method is effective.
Originality/value
A method based on contact mechanics is proposed and verified. Through the establishment of wheel-ground contact mechanics model to optimize MY3-OMR kinematics model, and thereby, the motion accuracy of MY3-OMR is improved, which lays a foundation for MY3-OMR engineering application.
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Noura AlNuaimi, Mohammad Mehedy Masud, Mohamed Adel Serhani and Nazar Zaki
Organizations in many domains generate a considerable amount of heterogeneous data every day. Such data can be processed to enhance these organizations’ decisions in real time…
Abstract
Organizations in many domains generate a considerable amount of heterogeneous data every day. Such data can be processed to enhance these organizations’ decisions in real time. However, storing and processing large and varied datasets (known as big data) is challenging to do in real time. In machine learning, streaming feature selection has always been considered a superior technique for selecting the relevant subset features from highly dimensional data and thus reducing learning complexity. In the relevant literature, streaming feature selection refers to the features that arrive consecutively over time; despite a lack of exact figure on the number of features, numbers of instances are well-established. Many scholars in the field have proposed streaming-feature-selection algorithms in attempts to find the proper solution to this problem. This paper presents an exhaustive and methodological introduction of these techniques. This study provides a review of the traditional feature-selection algorithms and then scrutinizes the current algorithms that use streaming feature selection to determine their strengths and weaknesses. The survey also sheds light on the ongoing challenges in big-data research.