Binrui Wang, Jiqing Huang, Guoyang Shen and Dijian Chen
Active compliance control is the key technology for Tri-Co robots (coexisting–cooperative–cognitive robots) to interact with the environment and people. This study aims to make…
Abstract
Purpose
Active compliance control is the key technology for Tri-Co robots (coexisting–cooperative–cognitive robots) to interact with the environment and people. This study aims to make the robot arm shake hands compliantly with people; the paper proposed two closed-loop-compliant control schemes for the dynamic identification of cascade elbow joint.
Design/methodology/approach
The active compliance control strategy consists of inner and outer loops. The inner loop is the position control using sliding mode control with disturbance observer (SMCDO), in which a new saturation function is designed to replace the traditional signal function of sliding mode control (SMC) law so as to mitigate chatter. The outer loop is the admittance control to regulate the dynamic behaviours of the elbow joint, i.e. its impedance. The simulation is carried out to verify the performance of the proposed control scheme.
Findings
The results show that the chatter of traditional SMC can be effectively eliminated by using SMCDO with this saturation function. In addition, for the handshake task, the value of threshold force and elbow joint compliance is defined. Then, the threshold force tests, impact tests and elbow-joint compliance tests are carried out. The results show that, in the impedance model, the elbow joint compliance only depends on the stiffness parameters, not on the position control loop.
Practical implications
The effectiveness of the admittance control based on SMCDO can improve the adaptability of industrial manipulator in different working environments to some degree.
Originality/value
The admittance control with SMCDO completed trajectory tracking has higher accuracy than that based on SMC.
Details
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Hailiang Su, Fengchong Lan, Yuyan He and Jiqing Chen
Meta-model method has been widely used in structural reliability optimization design. The main limitation of this method is that it is difficult to quantify the error caused by…
Abstract
Purpose
Meta-model method has been widely used in structural reliability optimization design. The main limitation of this method is that it is difficult to quantify the error caused by the meta-model approximation, which leads to the inaccuracy of the optimization results of the reliability evaluation. Taking the local high efficiency of the proxy model, this paper aims to propose a local effective constrained response surface method (LEC-RSM) based on a meta-model.
Design/methodology/approach
The operating mechanisms of LEC-RSM is to calculate the index of the local relative importance based on numerical theory and capture the most effective area in the entire design space, as well as selecting important analysis domains for sample changes. To improve the efficiency of the algorithm, the constrained efficient set algorithm (ESA) is introduced, in which the sample point validity is identified based on the reliability information obtained in the previous cycle and then the boundary sampling points that violate the constraint conditions are ignored or eliminated.
Findings
The computational power of the proposed method is demonstrated by solving two mathematical problems and the actual engineering optimization problem of a car collision. LEC-RSM makes it easier to achieve the optimal performance, less feature evaluation and fewer algorithm iterations.
Originality/value
This paper proposes a new RSM technology based on proxy model to complete the reliability design. The originality of this paper is to increase the sampling points by identifying the local importance of the analysis domain and introduce the constrained ESA to improve the efficiency of the algorithm.
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Hailiang Su, Fengchong Lan, Yuyan He and Jiqing Chen
Because of the high computational efficiency, response surface method (RSM) has been widely used in structural reliability analysis. However, for a highly nonlinear limit state…
Abstract
Purpose
Because of the high computational efficiency, response surface method (RSM) has been widely used in structural reliability analysis. However, for a highly nonlinear limit state function (LSF), the approximate accuracy of the failure probability mainly depends on the design point, and the result is that the response surface function composed of initial experimental points rarely fits the LSF exactly. The inaccurate design points usually cause some errors in the traditional RSM. The purpose of this paper is to present a hybrid method combining adaptive moving experimental points strategy and RSM, describing a new response surface using downhill simplex algorithm (DSA-RSM).
Design/methodology/approach
In DSA-RSM, the operation mechanism principle of the basic DSA, in which local descending vectors are automatically generated, was studied. Then, the search strategy of the basic DSA was changed and the RSM approximate model was reconstructed by combining the direct search advantage of DSA with the reliability mechanism of response surface analysis.
Findings
The computational power of the proposed method is demonstrated by solving four structural reliability problems, including the actual engineering problem of a car collision. Compared to specific structural reliability analysis methods, the approach of modified DSA interpolation response surface for structural reliability has a good convergent capability and computational accuracy.
Originality/value
This paper proposes a new RSM technology based on proxy model to complete the reliability analysis. The originality of this paper is to present an improved RSM that adjusts the position of the experimental points judiciously by using the DSA principle to make the fitted response surface closer to the actual limit state surface.
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Zhi Ding, Xiao Zhang, Xinsheng Yin and Jiqing Jiang
This paper aims to analyse the effect of soft soil grouting on the deformation of the closed shield tunnel with the measured data.
Abstract
Purpose
This paper aims to analyse the effect of soft soil grouting on the deformation of the closed shield tunnel with the measured data.
Design/methodology/approach
Combining the measured data of vertical, horizontal and convergence deformation of the adjacent tunnel during the grouting construction in foundation pit engineering, the influence of grouting on metro tunnel in soft soil area is analyzed.
Findings
The researches indicate that early grouting has the main effect on the horizontal displacement of the tunnel; Due to the disturbing effect of the uninterrupted grouting construction on the soil and the transfer pressure of the rheological soil to the bottom of the tunnel, the tunnel is obviously lifted; And the convergence deformation of the tunnel increases caused by the overburden pressure in the vertical direction, so that the tunnel appears the phenomenon of staggered seam, large opening of bolted joint, damaged segment even leakage of water.
Originality/value
The study based on the field monitoring data is rarely reported, especially the topic about inadvertent grouting in soft soil area is likely to cause severe deformation of adjacent metro tunnel.
Details
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Yu Xia, Jiqing Xie, Guangsi Zhang and Weijun Zhu
Upstream suppliers attempt to outsource product after-sales services to midstream third-party service providers while selling the product directly to downstream sellers, forming a…
Abstract
Purpose
Upstream suppliers attempt to outsource product after-sales services to midstream third-party service providers while selling the product directly to downstream sellers, forming a networked supply chain. However, a problem of information asymmetry in the market demand among supply chain members exists. The authors investigate the impact of demand information asymmetry among third-party service providers, upstream suppliers and downstream sellers in the supply chain on the supplier's contract selection under the networked framework.
Design/methodology/approach
The authors establish a model in which the supplier can use a wholesale price contract and facilitate a signaling game between the third-party service provider and the seller. Conversely, the supplier could use a menu contract to establish an incentive mechanism to solve information asymmetry. The authors propose heuristic algorithms to quickly estimate a supplier's optimal profit.
Findings
The results show that when the demand forecasting bias is relatively small, the use of a menu contract by the supplier could eliminate information asymmetry; when the demand forecasting bias is large enough, the signaling mechanism between the third-party service provider and the seller could alleviate the double marginalization effect in the supply chain. Although it is common to solve the asymmetric information problem by establishing incentive mechanisms, the authors found that in the latter case, the supplier is better off when no incentive mechanisms are implemented in the networked supply chain.
Originality/value
This study compares screening and signaling effects and compares firms' profits in both cases.
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Ling Liang, Jiqing Xie, Jie Ren, Jialiang Wang and Chang Wang
Information opacity in donation crowdfunding activities has constrained the healthy development of China’s public welfare activities. Addressing the trust crisis and enhancing…
Abstract
Purpose
Information opacity in donation crowdfunding activities has constrained the healthy development of China’s public welfare activities. Addressing the trust crisis and enhancing public engagement warrants further investigation. This study aims to uncover the moderating effect of activity transparency by utilizing data from 1,029 donation crowdfunding projects on the Sina Weibo Public Welfare Social Platform. In this way, we seek to elucidate the impact of donation crowdfunding events on fundraising ability.
Design/methodology/approach
This study selects text complexity, number of supporters, creator experience, and social capital as explanatory variables; innovatively selects the number of updates of online crowdfunding activities and total reading volume as moderating variables; selects the number of shares of crowdfunding activities as a mediating variable; and constructs a moderated mediation multiple regression model for fundraising ability.
Findings
Our findings indicate that independent variables, such as text complexity, number of supporters, and social capital, can significantly affect the dependent variable, fundraising ability. However, creator experience does not influence fundraising ability. Furthermore, social interaction has a mediating effect, whereas activity transparency has a reverse moderating effect. These results indicate that social interaction can enhance the fundraising ability of donation crowdfunding events. However, with an increase in information transparency, the fundraising ability of social media decreases.
Originality/value
The originality of this research is in clarifying the internal factors affecting fundraising ability through induction, making bold assumptions, and focusing on how social media’s effective interaction and activity transparency will affect public welfare crowdfunding fundraising ability.
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Haicheng Jia, Jing Li, Ling Liang, Weicai Peng, Jiqing Xie and Jiaping Xie
The development of low-carbon production is impeded by the investment costs of green technology research and development (R&D) and carbon emission reduction while facing the…
Abstract
Purpose
The development of low-carbon production is impeded by the investment costs of green technology research and development (R&D) and carbon emission reduction while facing the uncertain risk of emission reduction investment. With the government's carbon emission constraints, green manufacturers implement the advance selling strategy to increase both profit and reduction level. However, few studies consider the consumer's green preference and emission constraints in advance selling market and spot market independently. The authors' paper investigates the optimal strategies of advance selling pricing and reduction effort for green manufacturers to maximize profits.
Design/methodology/approach
The authors' paper designs a stochastic model and investigates the manufacturer's optimal strategies of advance selling price and emission reduction efforts by categorizing different purchasing periods of low-carbon consumers. With the challenges of uncertain demand and government's emission constraints, the authors' develop the non-linear optimization model to investigate the manufacturer's profit-oriented decisions.
Findings
The results show the government's carbon constraints cannot influence the manufacturer's profit, but the consumer's low-carbon preference in the advance selling period can. Interestingly, the manufacturer will make fewer reduction efforts even when the consumers have stronger environmental awareness. In addition, the increasing consumer price sensitivity will exacerbate the profit loss from mandatory emissions reduction. Overall, for achieving a win–win situation between emission reduction and profit growth, green manufacturers should not only consider the sales strategies, market demand, and government constraints in a low-carbon market, but also pay attention to the uncertainty of green technology innovation.
Originality/value
With the consideration of the government's carbon emission constraints, uncertain demand, and low-carbon consumer's preferences, the authors' study innovatively incorporates the joint impacts of advance selling strategy and emission reduction effort strategy and then differentiates between two cases that pertain to the diverse carbon emission regulations.
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Tanja Sargent, Mingyu Chen, Yi-Jung Wu and Chentong Chen
When college entrance examinations act as gatekeepers to modern-sector jobs, the entire education system then becomes oriented toward these examinations. This occurs at the…
Abstract
When college entrance examinations act as gatekeepers to modern-sector jobs, the entire education system then becomes oriented toward these examinations. This occurs at the expense of learning for the sake of learning and other aspects of education that address the holistic development and well-being of students. In recent years in China, there has been growing concern that examination competition has compromised the quality of classroom teaching and learning and is detrimental to the development of skills necessary for the global knowledge economy. These concerns have given rise to a far-reaching set of education reforms known as the New Curriculum reforms which have aimed to move students to the center of teaching and learning and to transform teaching and learning so as to foster such capacities as creativity, innovation, collaboration, self-expression, engagement, enjoyment of learning, inquiry skills, problem-solving abilities, and ability to apply knowledge in practice. In this chapter, we use videotaped high school New Curriculum demonstration lessons to examine teaching and learning practices that are regarded as exemplary in the current reform context. We investigate how teachers are negotiating the competing demands of preparing students for the examinations and addressing the aims of the New Curriculum reforms. The nature of student participation in the classroom emerges in the analysis as a key indicator of the success of this negotiation.
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During the centennial anniversary of Xinhai Revolution in 2011, the Chinese People’s Political Consultative Conference and the State Administration of Radio, Film, and Television…
Abstract
Purpose
During the centennial anniversary of Xinhai Revolution in 2011, the Chinese People’s Political Consultative Conference and the State Administration of Radio, Film, and Television supported the production of 1911 for celebrating such an important event that lead to the rise of the Republic of China in the contemporary Chinese history. This paper aims to reflect upon this film in relation to China’s propagation of “Greater China” for the Empire-building project.
Design/methodology/approach
By scrutinizing the film text and following the strait controversies over the film, this paper demonstrates how the Chinese Communist agents employed the coproduction model with Hong Kong for globalizing a cinematic discourse of Greater China in part of their Empire-building project.
Findings
The study challenges how contemporary Chinese history is ideologically and politically manipulated for advancing the Chinese Communist propaganda over Taiwan. The overall objective is to reflect upon the longstanding historical divergences that stand on the current geopolitical envision and strategy of China for reunification.
Originality/value
This paper provides an interdisciplinary reflection upon the intricate post-Cold War politics in part of the contemporary Chinese cinema under the China–Hong Kong coproduction model. The findings advance novel and timely insights into China’s current envision and strategy for reunification.