Fusheng Dai, Shuaifeng Zhang, Runsheng Li and Haiou Zhang
This paper aims to present a series of approaches for three-related issues in multiaxis in wire and arc additive manufacturing (WAAM) as follows: how to achieve a stable and…
Abstract
Purpose
This paper aims to present a series of approaches for three-related issues in multiaxis in wire and arc additive manufacturing (WAAM) as follows: how to achieve a stable and robust deposition process and maintain uniform growth of the part; how to maintain consistent formation of a melt pool on the surface of the workpiece; and how to fabricate an overhanging structure without supports.
Design/methodology/approach
The principal component analysis-based path planning approach is proposed to compute the best scanning directions of slicing contours for the generation of filling paths, including zigzag paths and parallel skeleton paths. These printing paths have been experimented with in WAAM. To maintain consistent formation of a melt pool at overhanging regions, the authors introduce definitions for the overhanging point, overhanging distance and overhanging vector, with which the authors can compute and optimize the multiaxis motion. A novel fabricating strategy of depositing the overhanging segments as a support for the deposition of filling paths is presented.
Findings
The second principal component of a planar contour is a reasonable scanning direction to generate zigzag filling paths and parallel skeleton filling paths. The overhanging regions of a printing layer can be supported by pre-deposition of overhanging segments. Large overhangs can be successfully fabricated by the multiaxis WAAM process without supporting structures.
Originality/value
An intelligent approach of generating zigzag printing paths and parallel skeleton printing paths. Optimizations of depositing zigzag paths and parallel skeleton paths. Applications of overhanging point overhanging distance and overhanging vector for multiaxis motion planning. A novel fabricating strategy of depositing the overhanging segments as a support for the deposition of filling paths.
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Fusheng Dai, Haiou Zhang and Runsheng Li
The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the…
Abstract
Purpose
The study aims to fabricate large metal components with overhangs built on cylindrical or conical surfaces with a high dimensional precision. It proposes methods to address the problems of generating tool-paths on cylindrical or conical surfaces simply and precisely, and planning the welding process on these developable surfaces.
Design/methodology/approach
The paper presents the algorithm of tool-paths planning on conical surfaces using a parametric slicing equation and a spatial mapping method and deduces the algorithm of five-axis transformation by addressing the rotating question of two sequential points. The welding process is investigated with a regression fitting model on a flat surface, and experimented on a conical surface, which can be flattened onto a flat surface.
Findings
The paper provides slicing and path-mapping expressions for cylindrical and conical surfaces and a curvature-speed-width (CSW) model for wire and arc additive manufacturing to improve the surface appearances. The path-planning method and CSW model can be applied in the five-axis fabrication of the prototype of an underwater thruster. The CSW model has a confidence coefficient of 98.02% and root mean squared error of 0.2777 mm. The reverse measuring of the finished blades shows the residual deformation: an average positive deformation of about 0.5546 mm on one side of the blades and an average negative deformation of about −0.4718 mm on the other side.
Research limitations/implications
Because of the chosen research approach, the research results may lack generalizability for the fabrication based on arbitrary surfaces.
Originality/value
This paper presented an integrated slicing, tool-path planning and welding process planning method for five-axis wire and arc additive manufacturing.
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Runsheng Li, Haiou Zhang, Fusheng Dai, Cheng Huang and Guilan Wang
Large-scale aircraft parts usually with many frame features, which consist of intersections. Profile and tensile properties of junctions in wire and arc additive manufacturing…
Abstract
Purpose
Large-scale aircraft parts usually with many frame features, which consist of intersections. Profile and tensile properties of junctions in wire and arc additive manufacturing (WAAM) are significantly affected by path strategies. The purpose of this paper is to propose a novel path strategy for intersections in WAAM and compare it with commonly used ones.
Design/methodology/approach
Three typical intersections including T crossing (TC), square crossing (SC) and arbitrary-angle crossing (AAC) were built up with two commonly used path strategies (parallel and oscillation) and a proposed method named end lateral extension (ELE) which extends the weld track along the crossed direction. A robotic system and cold metal transfer (CMT) process were used to deposit Al-6.3Cu (2319) alloy. The profile of the bead was scanned by laser vision sensor. Tightened ratio (r), inter-layer height increment (Δh) and deviation to the fitting plane (df) are calculated based on the point cloud. Tensile tests were done for all built intersections.
Findings
Comparison to the commonly used path strategies, the proposed ELE method eliminated the tightened defects at the intersection, achieved a more stable inter-layer height increment (Δh) and improved the profile quality with a lower deviation to the fitting plane (df). Tensile tests show that the proposed strategy has exhibited favorable tensile properties.
Originality/value
In this paper, a novel path strategy named ELE is proposed, which provides a new path choice for fabricating intersections by WAAM.
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Xiyue Zheng, Fusheng Wang and Dongchao Zhang
The purpose of this study is to explore the influence of venture capital participation on corporate innovation and to assess how internationalization strategies (including both…
Abstract
Purpose
The purpose of this study is to explore the influence of venture capital participation on corporate innovation and to assess how internationalization strategies (including both the internationalization scope and speed) in mediating serve as intermediaries in the relationship between venture capital and corporate innovation.
Design/methodology/approach
Using hierarchical regression analysis, this research tests the hypothesized framework using survey data collected from 442 high-tech enterprises listed on the A-share markets in Shanghai and Shenzhen, China, spanning from 2010 to 2019.
Findings
The study reveals a non-linear (U-shaped) correlation between venture capital investment and innovation. This non-linear linkage is facilitated through the execution of enterprises’ strategies for international expansion. The primary finding suggests that venture capital participation positively influences the rapidity and extent of internationalization. Additionally, a U-shaped relationship is observed between corporate innovation and both the speed and scope of internationalization.
Originality/value
This document contributes insights into the micro-level mechanisms that explain the effects of venture capital and internationalization strategy on corporate innovation. The results offer multinational corporations practical guidance for executing their internationalization strategies effectively and fostering innovation.
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Fusheng Liu, Zhihang He, Yue Qiao, Xinxin Liu, Xuelong Li, Wang Wei, Bo Su and Ruina Dang
The purpose of this paper is specifically to provide a more intelligent locomotion planning method for a hexapod robot based on trajectory optimization, which could reduce the…
Abstract
Purpose
The purpose of this paper is specifically to provide a more intelligent locomotion planning method for a hexapod robot based on trajectory optimization, which could reduce the complexity of locomotion design, shorten time of design and generate efficient and accurate motion.
Design/methodology/approach
The authors generated locomotion for the hexapod robot based on trajectory optimization method and it just need to specify the high-level motion requirements. Here the authors first transcribed the trajectory optimization problem to a nonlinear programming problem, in which the specified motion requirements and the dynamics with complementarity constraints were defined as the constraints, then a nonlinear solver was used to solve. The leg compliance was taken into consideration and the generated motions were deployed on the hexapod robot prototype to prove the utility of the method and, meanwhile, the influence of different environments was considered.
Findings
The generated motions were deployed on the hexapod robot and the movements were demonstrated very much in line with the planning. The new planning method does not require lots of parameter-tuning work and therefore significantly reduces the cycle for designing a new locomotion.
Originality/value
A locomotion generation method based on trajectory optimization was constructed for a 12-degree of freedom hexapod robot. The variable stiffness compliance of legs was considered to improve the accuracy of locomotion generation. And also, different from some simulation work before, the authors have designed the locomotion in three cases and constructed field tests to demonstrate its utility.
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Abstract
Details
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Wei Guo, Shiyin Qiu, Fusheng Zha, Jing Deng, Xin Wang and Fei Chen
This paper aims to propose a novel balance-assistive control strategy for hip exoskeleton robot.
Abstract
Purpose
This paper aims to propose a novel balance-assistive control strategy for hip exoskeleton robot.
Design/methodology/approach
A hierarchical balance assistive controller based on the virtual stiffness model of extrapolated center of mass (XCoM) is proposed and tested by exoskeleton balance assistive control experiments.
Findings
Experiment results show that the proposed controller can accelerate the swing foot chasing XCoM and enlarge the margin of stability.
Originality/value
As a proof of concept, this paper shows the potential for exoskeleton to actively assist human regain balance in sagittal plane when human suffers from a forward or backward disturbing force.
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Fengwen Chen, Lu Zhang, Fu-Sheng Tsai and Bing Wang
This study focuses on the self-organized cooperative consumption of platform participants on social media platform, and reveals how the brand owner cooperates with two-sided…
Abstract
Purpose
This study focuses on the self-organized cooperative consumption of platform participants on social media platform, and reveals how the brand owner cooperates with two-sided customers to achieve value co-creation.
Design/methodology/approach
The authors adopted a case study approach to explore how a Chinese beauty startup developed collaborative networks from 2013 to 2022, and tracked the the changes of network structure and cooperation mechanism.
Findings
The study finds that the brand owner cooperates with two-sided customers to integrate resources and establish diverse relational trust, which enhances the evolution of a heterogeneous collaborative network for value co-creation.
Originality/value
The study builds upon traditional dyadic actor-to-actor interactions between providers and customers, develops a novel interaction framework of actor-to-network to explain the value co-creation by collaborative networking, reveals the self-organized mechanism of cooperative consumption on social media.
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Xianchun Zhang, Zhu Yao, Wan Qunchao and Fu-Sheng Tsai
Time pressure is the most common kind of work pressure that employees face in the workplace; the existing research results on the effect of time pressure are highly controversial…
Abstract
Purpose
Time pressure is the most common kind of work pressure that employees face in the workplace; the existing research results on the effect of time pressure are highly controversial (positive, negative, inverted U-shaped). Especially in the era of knowledge economy, there remains a research gap in the impact of time pressure on individual knowledge hiding. The purpose of this paper is to explore the impact of different time pressure (challenge and hindrance) on knowledge hiding and to explain why there is controversy about the effect of time pressure in the academics.
Design/methodology/approach
The authors collected two waves of data and surveyed 341 R&D employees in China. Moreover, they used regression analysis, bootstrapping and Johnson–Neyman statistical technique to verify research hypotheses.
Findings
The results show that challenge time pressure (CTP) has a significant negative effect on knowledge hiding, whereas hindrance time pressure (HTP) has a significant positive effect on knowledge hiding; job security mediates the relationship between time pressure and knowledge hiding; temporal leadership strengthen the positive impact of CTP on job security; temporal leadership can mitigate the negative impact of HTP on job security.
Originality/value
The findings not only respond to the academic debate about the effect of time pressure and point out the reasons for the controversy but also enhance the scholars’ attention and understanding of the internal mechanism between time pressure and knowledge hiding.
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Fashu Xu, Rui Huang, Hong Cheng, Min Fan and Jing Qiu
This paper aims at the problem of attaching the data of doctors, patients and the real-time sensor data of the exoskeleton to the cloud in intelligent rehabilitation applications…
Abstract
Purpose
This paper aims at the problem of attaching the data of doctors, patients and the real-time sensor data of the exoskeleton to the cloud in intelligent rehabilitation applications. This study designed the exoskeleton cloud-brain platform and validated its safety assessment.
Design/methodology/approach
According to the dimension of data and the transmission speed, this paper implements a three-layer cloud-brain platform of exoskeleton based on Alibaba Cloud's Lambda-like architecture. At the same time, given the human–machine safety status detection problem of the exoskeleton, this paper built a personalized machine-learning safety detection module for users with the multi-dimensional sensor data cloned by the cloud-brain platform. This module includes an abnormality detection model, prediction model and state classification model of the human–machine state.
Findings
These functions of the exoskeleton cloud-brain and the algorithms based on it were validated by the experiments, they meet the needs of use.
Originality/value
This thesis innovatively proposes a cloud-brain platform for exoskeletons, beginning the digitalization and intelligence of the exoskeletal rehabilitation process and laying the foundation for future intelligent assistance systems.