Gang Zhang, Jianhua Wu, Pinkuan Liu and Han Ding
Based on the inverse kinematics and task space dynamic model, this paper aims to design a high-precision trajectory tracking controller for a 2-DoF translational parallel…
Abstract
Purpose
Based on the inverse kinematics and task space dynamic model, this paper aims to design a high-precision trajectory tracking controller for a 2-DoF translational parallel manipulator (TPM) driven by linear motors.
Design/methodology/approach
The task space dynamic model of a 2-DoF TPM is derived using Lagrangian equation of the first type. A task space dynamic model-based feedforward controller (MFC) is designed, which is combined with a cascade PID/PI controller and velocity feedforward controller (VFC) to construct a hybrid PID/PI+VFC/MFC controller. The hybrid controller is implemented in MATLAB/dSPACE real-time control platform. Experiment results are given to validate the effectiveness and industrial applicability of the hybrid controller.
Findings
The MFC can compensate for the nonlinear dynamic characteristics of a 2-DoF TPM and achieve better tracking performance than the conventional acceleration feedforward controller (AFC).
Originality/value
The task space dynamic model-based hybrid PID/PI+VFC/MFC controller is proposed for a 2-DoF linear-motor-driven TPM, which reduces the tracking error by at least 15 percent compared with conventional hybrid PID/PI+VFC/AFC controller. This control scheme can be extended to high-speed and high-precision trajectory tracking control of other parallel manipulators by reprogramming the feedforward signals of traditional cascade PID/PI controller.
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Jicun Lu, Jianhua Wu, Yih Pin Liew, Thiam Beng Lim and Xiangfu Zong
The impact of underfill properties on the thermomechanical reliability of flip chip on board (FCOB) assembly is addressed in this paper. FCOB assemblies using three underfill…
Abstract
The impact of underfill properties on the thermomechanical reliability of flip chip on board (FCOB) assembly is addressed in this paper. FCOB assemblies using three underfill encapsulants were subjected to a thermal cycling test. The performance of the underfill encapsulants was assessed by a statistical analysis of the failure distribution of the FCOB assemblies. The failure modes in the thermal cycling test were found to be solder joint cracks, delamination at underfill/chip passivation interface, and underfill internal cracks. An attempt was made to correlate these failures with underfill properties such as the coefficient of thermal expansion (CTE), modulus, glass transition temperature (Tg), and adhesive strength to the chip. Additionally, nonlinear finite element analysis (FEA) was conducted to verify the experimental results.
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DongLin Pu, JianHua Wu, ZhenHua Xiong, XinJun Sheng and Han Ding
The purpose of this paper is to explore the nonlinear analysis on the relay feedback technology (RFT) applied to parameters identification of servo mechanism.
Abstract
Purpose
The purpose of this paper is to explore the nonlinear analysis on the relay feedback technology (RFT) applied to parameters identification of servo mechanism.
Design/methodology/approach
In order to investigate nonlinear elements' influence on RFT, the analysis was conducted in the velocity and current control loops, respectively. The RFT algorithm for modeling servo mechanism with friction was developed to overcome the nonlinear influence. Furthermore, the results from experiments were presented to validate the analysis and illustrated the advantages of the proposed method.
Findings
The Coulomb friction and current changing are the main nonlinear influence on the RFT application in servo mechanism. The friction effects should be included to servo system modeling based on RFT.
Practical implications
Some suggestions concluded from nonlinear analysis are useful to optimize the selection of parameters in RFT. And the proposed algorithm is applicable to modeling servo mechanism with friction.
Originality/value
The nonlinear analysis in the different control loops of servo mechanism based on RFT is presented and the effective identification approach is proposed in this paper.
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Peng Dong, Shengdun Zhao, Shuqin Fan, Muzhi Zhu and Peng Zhang
The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump…
Abstract
Purpose
The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump with through shaft driving and valve plate distribution.
Design/methodology/approach
The working principle of the pump is discussed in detail. In this radial piston pump, valve plate distribution parts are designed to distribute oil to the piston chambers, and the distribution shaft is replaced. A bearing is installed between the stator and rotator to reduce the friction. The transmission shaft is supported by two bearings to ensure smooth operation. The support force of the transmission shaft is optimized. In addition, the flow pulsation principle is presented. To accomplish the change, the displacement of the radial piston pump, the proportional control system is designed.
Findings
After completing the machining and assembly of the pump, an experimental study was carried out. The results show that the output flow of the pump is basically the same as the theoretical flow.
Originality/value
The friction between the slipping shoes and the stator is greatly reduced due to the function of rolling bearings. The higher stability of the driveshaft is obtained for the reason of double-sided support. The radial piston pump has a novel structural design in reducing the friction between the shoes and the stator and improving the stability of the transmission shaft.
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Jianhua Liu, Zibo Wu, Jiajia Liu and Yao Zou
In order to solve the problem of how to reduce the service delay of edge computing, this paper proposes an edge cloud framework, which contains four groups under different…
Abstract
Purpose
In order to solve the problem of how to reduce the service delay of edge computing, this paper proposes an edge cloud framework, which contains four groups under different locations between mobile edge nodes and users. A feasible cost scheme can be obtained by calculating the cost in different simulation groups. Furthermore, we give suggestions on how to deploy edge nodes at a reasonable cost for users effectively.
Design/methodology/approach
This paper is motivated by the IoT-Cloud framework; they are divided according to whether the nodes have templates required by users and the distance from users to distinguish various consumption levels and classify the testing result. Based on four different groups satisfying reasonable resource allocation, the cost was studied. The work focuses on the unpredictable movement within the test range. For assignment and scheduling of template tasks at each time slot, the Edge-Cloud scheme is proposed to reduce the cost.
Findings
According to the simulation results in this paper, the total cost of the four groups is lower when the closest node-set satisfies the user service directly. To improve the probability that the closest node-set can meet general requests of users and provide them with faster and more economical network services, increasing the number of edge nodes within the range of user activities is suggested.
Originality/value
An Edge-Cloud framework is constructed in four groups, and the conclusion of a feasible cost scheme came out.
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Linhai Wu, Qipeng Hu, Jianhua Wang and Dian Zhu
In China, a major grain producer, rice losses during harvest cannot be ignored. The purpose of this paper is to assess the extent of rice harvest losses in major grain-producing…
Abstract
Purpose
In China, a major grain producer, rice losses during harvest cannot be ignored. The purpose of this paper is to assess the extent of rice harvest losses in major grain-producing areas in China by a sampling survey, and to further analyze the main factors influencing rice harvest losses using an ordered multinomial logistic model.
Design/methodology/approach
In this study, data were collected using a multi-stage sampling method from ten major rice-producing provinces/regions in China. On this basis, five counties were selected from each of these provinces/regions. In the actual survey, house numbers were randomly selected, and then corresponding farmer households were visited by trained investigators.
Findings
The survey found that 56.22 percent of respondents believed that rice harvest losses were 4 percent or lower in China, though there were differences among the provinces. The proportion of family business income, planting scale, mechanization level, timely harvest, and operational meticulousness had negative effects on rice harvest losses. On the other hand, farmers’ experience of employment as migrant workers had a positive effect on rice harvest losses. In addition, bad weather and short handedness during harvest significantly increased rice harvest losses.
Originality/value
The meaning of rice harvest losses was defined based on previous research findings on the definition of grain harvest losses and the realities in China. The current rice harvest losses in different areas in China were analyzed based on sampling survey data from 957 farmers in ten provinces in China.
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Tingting Hou, Shixuan Fu, Yichen Cao, Xiaojiang Zheng and Jianhua (Jordan) Yu
This research is motivated by the increasing need for international interactions during the gradual recovery of the tourism industry. By recognizing the paucity of research on…
Abstract
Purpose
This research is motivated by the increasing need for international interactions during the gradual recovery of the tourism industry. By recognizing the paucity of research on cultural closeness and accommodation categories, this research aims to illuminate the influencing mechanisms of psychological closeness and travelers’ willingness to book an accommodation-sharing property while booking an accommodation.
Design/methodology/approach
The authors employ a mixed-methods approach, including an experiment and semistructured interviews.
Findings
Results show that hosts’ higher cultural identity congruence leads to travelers’ higher willingness to book an accommodation-sharing property. Psychological closeness mediates the positive effect of cultural identity congruence on travelers’ willingness to book. The authors further explore the moderating role of room types (entire room vs. private room) and find that the mediation effect is stronger for booking an entire room.
Originality/value
The current research underlines the importance of cultural identity congruence and accommodation type on travelers’ willingness to book an accommodation-sharing property and psychological closeness.
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Zhiwei Li, Dingding Li, Yulong Zhou, Haoping Peng, Aijun Xie and Jianhua Wang
This paper aims to contribute to the performance improvement and the broader application of hot-dip galvanized coating.
Abstract
Purpose
This paper aims to contribute to the performance improvement and the broader application of hot-dip galvanized coating.
Design/methodology/approach
First, the ability to provide barrier protection, galvanic protection, and corrosion product protection provided by hot-dip galvanized coating is introduced. Then, according to the varying Fe content, the growth process of each sublayer within the hot-dip galvanized coating, as well as their respective microstructures and physical properties, is presented. Finally, the electrochemical corrosion behaviors of the different sublayers are analyzed.
Findings
The hot-dip galvanized coating is composed of η-Zn sublayer, ζ-FeZn13 sublayer, δ-FeZn10 sublayer, and Γ-Fe3Zn10 sublayer. Among these sublayers, with the increase in Fe content, the corrosion potential moves in a noble direction.
Research limitations/implications
There is a lack of research on the corrosion behavior of each sublayer of hot-dip galvanized coating in different electrolytes.
Practical implications
It provides theoretical guidance for the microstructure control and performance improvement of hot-dip galvanized coatings.
Originality/value
The formation mechanism, coating properties, and corrosion behavior of different sublayers in hot-dip galvanized coating are expounded, which offers novel insights and directions for future research.
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Shixuan Fu, Jianhua Jordan Yu, Huimin Gu and Xiaoxiao Song
Shifting to OLSL classes during the pandemic can bring learners ambivalent experiences: negative, positive or both appraisals toward the technologies. However, few studies have…
Abstract
Purpose
Shifting to OLSL classes during the pandemic can bring learners ambivalent experiences: negative, positive or both appraisals toward the technologies. However, few studies have examined how ambivalent experiences can influence students' learning behaviors, specifically cyberslacking and active participation. Using the challenge-hindrance stressor framework, this study investigates the impact of challenge and hindrance appraisals on these learning behaviors.
Design/methodology/approach
This study uses a mixed methods approach to answer research questions. An interview was conducted to identify the key components of ambivalent appraisals, and a survey was conducted to empirically examine the impact of challenge and hindrance appraisals on learners' behaviors in online live streaming learning (OLSL) contexts. The data of 675 university students were analyzed using structural equation modeling.
Findings
This study found that hindrance appraisal leads to cyberslacking while challenge appraisal leads to active participation, but it can also cause cyberslacking. Social presence has a double-edged effect, acting as both a facilitator and inhibitor, strengthening the effect of hindrance appraisal on cyberslacking and the impact of challenge appraisal on active participation.
Originality/value
Prior studies have primarily focused on the negative side (techno-distress) of technology appraisals. This study simultaneously examines the positive side, techno-eustress, on learners' behaviors in OLSL contexts, and explores the moderating effects of social presence. This study contributes to the technostress and technology adaptation literature by revealing how technology-induced ambivalent appraisals impact behavioral responses. It offers important theoretical and practical implications for education tool designers.
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Abdul Hakeem Waseel, Jianhua Zhang, Muhammad Usman Shehzad, Irshad Hussain Sarki and Muhammad Wajid Kamran
This study examines the link between the knowledge creation process, ambidextrous innovation, and competitive advantage. Further, this study also tested the moderating role of…
Abstract
Purpose
This study examines the link between the knowledge creation process, ambidextrous innovation, and competitive advantage. Further, this study also tested the moderating role of organizational agility on the relationship between the knowledge creation process and ambidextrous innovation.
Design/methodology/approach
The empirical study’s data were collected by surveying 306 respondents employed in 140 Pakistani Small and Medium Enterprises (SMEs). The questionnaire was designed according to the study’s requirements and was based on theoretical knowledge and findings from previous research on the knowledge-creation process, ambidextrous innovation, and competitive advantage. All hypotheses were tested using a structured regression method.
Findings
The study indicates that the knowledge creation process significantly impacts a firm’s competitive advantage. Additionally, this study demonstrates that ambidextrous innovation can moderate the relationship between the knowledge-creation process and competitive advantage.
Research limitations/implications
Future studies should examine mediating factors, such as organizational culture, leadership style, and industry characteristics, as well as moderating variables, such as environmental turbulence.
Practical implications
This study guides SME leaders on the importance of knowledge creation and ambidextrous innovation in achieving operational success and gaining a competitive advantage.
Originality/value
This study explores how the knowledge creation process directly and indirectly, enhances organizational capacity for competitive advantage through the mediating roles of ambidextrous innovation and the moderating role of organizational agility.