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1 – 6 of 6Gang Chen, Wei‐gong Zhang and Xiao‐na Zhang
The paper aims to overcome the shortcomings that proportional‐integral‐derivative (PID) control for unmanned robot applied to automotive test (URAT) needs a priori manual…
Abstract
Purpose
The paper aims to overcome the shortcomings that proportional‐integral‐derivative (PID) control for unmanned robot applied to automotive test (URAT) needs a priori manual retuning, has large speed fluctuations and is hard to adjust control parameters. A novel control approach based on fuzzy neural network applied to URAT was proposed.
Design/methodology/approach
According to the target vehicle speed and driving command table, the multiple manipulator coordinated control model was established. After that, the displacement of throttle mechanical leg, clutch mechanical leg, brake mechanical leg and shift mechanical arm for URAT was used as input of fuzzy neural network (FNN) model, and vehicle speed was used as output of FNN model. The number of membership functions was three, and the type of that was generalized bell membership function (gbellmf). The hybrid learning algorithm which combined with back propagation algorithm and least square method was applied to train the model. The Sugeno model was selected as fuzzy reasoning model.
Findings
Experimental results demonstrated that compared with PID control method, the proposed approach can greatly improve the accuracy of vehicle speed tracking. The approach can accurately realize the vehicle speed tracking of given driving test cycle. Therefore, it can ensure the accuracy and effectiveness of automotive test results.
Research limitations/implications
Future work will focus on improving the efficiency of this learning algorithm.
Practical implications
The paper provides effective methods for improving the accuracy of speed tracking and repeatability.
Originality/value
After establishing the multiple manipulator coordinated control model, this paper proposes a novel control approach based on FNN for URAT.
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The purpose of this paper is to present a prototype simulation system for driving performance of an electromagnetic unmanned robot applied to automotive test (URAT) to solve that…
Abstract
Purpose
The purpose of this paper is to present a prototype simulation system for driving performance of an electromagnetic unmanned robot applied to automotive test (URAT) to solve that it is difficult and dangerous to online debug control program and to quickly obtain test vehicle dynamic performance.
Design/methodology/approach
The driving performance of the electromagnetic URAT can be evaluated by the prototype simulation system. The system can simulate various driving conditions of test vehicles. An improved vehicle longitudinal dynamics model matching to the electromagnetic URAT is established. The proposed model has good real-time, and it is easy to implement. The displacement of throttle mechanical leg, brake mechanical leg, clutch mechanical leg and shift mechanical arm is used for the system input. Test vehicle speed and engine speed are used for the system output, and they are obtained by the computation of the established vehicle longitudinal dynamics model.
Findings
Driving conditions simulation test and vehicle emission test are performed using a Ford Focus car. Simulation and experiment results show that the proposed prototype simulation system in the paper can simulate the driving conditions of actual vehicles, and the performance that electromagnetic URAT drives an actual vehicle is evaluated by the simulation system.
Research limitations/implications
Future research will focus on improving the real time of the proposed simulation system.
Practical implications
The autonomous driving performance of electromagnetic URAT can be evaluated by the proposed prototype simulation system.
Originality/value
A prototype simulation system for driving performance of an electromagnetic URAT based on an improved vehicle longitudinal dynamics model is proposed in this paper, so that it can solve the difficulty and danger of online debugging control program, quickly obtaining the test vehicle performance.
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Dong Wang, Guoyu Lin, Wei-gong Zhang, Ning Zhao and Han Pang
One of the major shortcomings in the data process of the traditional wheel force transducers (WFTs) is the theoretical errors of initial value determination. A new method to…
Abstract
Purpose
One of the major shortcomings in the data process of the traditional wheel force transducers (WFTs) is the theoretical errors of initial value determination. A new method to identify the initial values of the WFT for the solution of this problem is proposed in this paper. The paper aims to discuss these issues.
Design/methodology/approach
With this method, the initial values can be obtained by equations which are established based on multiple stops on horizontal road.
Findings
The calibration and contrast tests on the MTS calibration platform illustrate the better performance with the new method. Moreover, the real vehicle test confirms the effectiveness in practice.
Originality/value
The test results show that the new method of initial calibration has an advanced performance compared to the traditional one. In addition, it is effective in the brake test with a real vehicle.
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Wei Gong, Xiao-Yan Wang, Xiao Wang, Wen Wang and Yan-Li Yang
To ensure the reliable and safe operation of elevated-temperature pipes and equipment in the long term, it is essential to thoroughly assess the creep rupture life. Nevertheless…
Abstract
Purpose
To ensure the reliable and safe operation of elevated-temperature pipes and equipment in the long term, it is essential to thoroughly assess the creep rupture life. Nevertheless, there is currently no design code that specifies a creep rupture life evaluation method for non-nuclear elevated-temperature equipment. The paper aims to discuss this issue.
Design/methodology/approach
An analysis was conducted to compare the differences and conservativeness in calculating creep strain using three major codes (ASME-CC-2843, API-579 and BS-7910) based on the results of the 316H creep constitutive model and creep strain prediction. In addition, the creep resistances of 316H, 304H and 347H were compared. Subsequently, the ANSYS Usercreep subroutine was developed to compare the discrepancies between different codes under multiaxial stress conditions using numerical simulations.
Findings
BS-7910 employs the Norton creep model with calculation parameters for the average creep strain rate, which is not applicable for the engineering design stage. ASME-CC2843 code primarily focuses on the primary and secondary creep stages, making it more suitable for non-nuclear pipeline and equipment design. For 316H, the creep strain curves predicted by ASME-CC2843 and API-579 typically intersect at a specific point. By combining the creep strain predicted by ASME-CC2843 and API-579, 347H exhibits superior predicted creep resistance compared to 316H, whereas 316H exhibited better predicted creep resistance than 304H.
Originality/value
This study provides a guide for future evaluation methods and material choices for non-nuclear equipment and pipelines operating at elevated temperatures.
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Cheche Duan, Yicheng Zhou, Yuanqing Cai, Wei Gong, Chunzhen Zhao and Jian Ai
This paper investigates the relationship between human capital, economic freedom, governance performance, and economic growth and whether institutional factors such as governance…
Abstract
Purpose
This paper investigates the relationship between human capital, economic freedom, governance performance, and economic growth and whether institutional factors such as governance performance and economic freedom mediate the association between human capital and economic growth.
Design/methodology/approach
In this study, the authors apply the panel data regression method to verify five hypotheses and check the robustness of the empirical findings from four aspects (chow test, panel unit root test, granger test and generalized method of moments) based on the data covering China, India, Russia, Brazil and South Africa from 2000 to 2018.
Findings
After multiple tests with mixed methods, the empirical results show that the relationship between human capital and economic growth is not linear but inverted U-shaped. Furthermore, human capital has a positive effect on economic growth only in a certain period of time, and governance performance positively moderates the effect of human capital on economic growth in BRICS.
Originality/value
First, the impact of human capital on economic growth is not linear but an inverted U-shaped and governance performance moderates the effect of human capital on economic growth in BRICS. The study and research model enhances the authors’ insights on the advantage and challenges of human capital in the future. Second, the proposed multi-methods in the study accurately forecast economic growth which partially solves endogenous problems because of reverse causality.
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This study aims to analyze the subsequent investment success of EMNCs after their strategic asset-seeking foreign direct investments (FDIs), while internationalization…
Abstract
Purpose
This study aims to analyze the subsequent investment success of EMNCs after their strategic asset-seeking foreign direct investments (FDIs), while internationalization trajectories of multinational corporations from emerging economies (EMNCs) have been extensively studied, Post-internationalization investment success of EMNCs is defined as extensive technological knowledge access and transfer for knowledge combination. This paper focuses on EMNC explicit knowledge access and transfer.
Design/methodology/approach
This study analyzes US patents granted between 2000 and 2014 to leading innovation-oriented EMNCs from China and India as well as to their key competitors from mature industrialized countries (MMNCs). Wilcoxon Rank Sum Test is used to compare the explicit technological knowledge access and transfer patterns of EMNCs and MMNCs. With MMNCs as the benchmark, the comparison allows to imply the patterns and extent of technological knowledge access and transfer of EMNCs.
Findings
While subsidiary reverse knowledge transfer is largely missing, EMNCs adopt a parent-centric approach in which the parent directly accesses and transfers explicit knowledge from the external environment of host locations. In doing so, EMNCs at least partially achieve the knowledge access and transfer goals of strategic asset-seeking FDIs.
Originality/value
This study contributes to an in-depth understanding of EMNCs by empirically testing key predictions in extant EMNC literature, namely, the strategic asset-seeking in host locations and the systematic integration of accessed knowledge and resources with home country activities. This study also pioneers the use of the US patent and citation data to empirically study EMNCs.
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