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Article
Publication date: 9 February 2021

Hao Guo, Feng Ju, Ning Wang, Bai Chen, Xiaoyong Wei, Yaoyao Wang and Dan Wang

Continuum manipulators are often used in complex and narrow space in recent years because of their flexibility and safety. Vision is considered to be one of the most…

Abstract

Purpose

Continuum manipulators are often used in complex and narrow space in recent years because of their flexibility and safety. Vision is considered to be one of the most direct methods to obtain its spatial shape. However, with the improvement of the cooperation requirements of multiple continuum manipulators and the increase of space limitation, it is impossible to obtain the complete spatial shape information of multiple continuum manipulators only by several cameras.

Design/methodology/approach

This paper proposes a fusion method using inertial navigation sensors and cameras to reconstruct the shape of continuum manipulators in the whole workspace. The camera is used to obtain the position information, and the inertial navigation sensor is used to obtain the attitude information. Based on the above two information, the shape of the continuum manipulator is reconstructed by fitting Bézier curve.

Findings

The experiment result of single continuum manipulator shows that the cubic Bézier curves is applicable to curve fitting of variable curvature, the maximum fitting error is about 2 mm. Meanwhile, the experiment result shows that this method is not affected by obstacles and can still reconstruct the shape of the continuum manipulators in 3-D space by detecting the position and attitude information of the end.

Originality/value

According to the authors’ knowledge, this is the first study on spatial shape reconstruction of multiple continuum manipulators and the first study to introduce inertial navigation sensors and cameras into the field of shape reconstruction of multiple continuum manipulators in narrow space. This method is suitable for shape reconstruction of manipulator with variable curvature continuum manipulator. When the vision of multiple continuum manipulators is blocked by obstacles, the spatial shape can still be reconstructed only by exposing the end point. The structure is simple, but it has certain accuracy within a certain range.

Details

Industrial Robot: the international journal of robotics research and application, vol. 48 no. 3
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 6 April 2020

Jing Yang, Jie Zhong, Fang Xie, Xiaoyang He, Liwen Du, Yaqian Yan, Meiyu Li, Wuqian Ma, Wenxin Wang and Ning Wang

The purpose of this work is to controllably synthesize a carbon aerogel with programmable functionally graded performance via a simple and effective strategy.

Abstract

Purpose

The purpose of this work is to controllably synthesize a carbon aerogel with programmable functionally graded performance via a simple and effective strategy.

Design/methodology/approach

This work uses polyvinyl alcohol (PVA) via the controllable sol-gel, lyophilization, and carbonization approach to achieve a programmable carbon aerogel. This design has the advantages of low raw material and preparation cost, simple and controllable synthetic process and low carbonization temperature.

Findings

The thermal stability and microstructure of PVA aerogel can be controlled by the crosslinking agent content within a certain range. The crosslinking agent content and the carbonization temperature are the key factors for functionally graded programming of carbon aerogels, including microstructure, oxygen-containing functional groups and adsorption performance. The adsorption ratio and adsorption rate of uranium can be controlled by adjusting initial concentration and pH value of the uranium solution. The 2.5%25 carbon aerogel with carbonization temperature of 350 °C has excellent adsorption performance when the initial concentration of uranium solution is 32 ppm at pH 7.5.

Research limitations/implications

As a new type of lightweight nano-porous amorphous carbon material, this carbon aerogel has many excellent properties.

Originality/value

This work presents a simple, low cost and controllable strategy for functionally graded programming of novel carbon aerogel. This carbon aerogel has great potential for application in various fields such as uranium recovery, wastewater treatment, sound absorption and shock absorption.

Details

Pigment & Resin Technology, vol. 50 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 23 January 2019

Ning Wang and Maryna Murdock

This paper aims to revisit the assumption of the cyclicality of the property-liability insurance market and identify a scenario in which the so-called underwriting cycles…

Abstract

Purpose

This paper aims to revisit the assumption of the cyclicality of the property-liability insurance market and identify a scenario in which the so-called underwriting cycles are unpredictable, according to a dynamic cash flow model which generates non-cyclical output dynamics.

Design/methodology/approach

This paper is on the intersection of real business cycle models and financial cycles. The authors construct a dynamic model of an insurer’s cash flows with stochastic loss shocks and capacity constraints, in which loss shocks have a dual impact on both underwriting profits and access to external capital. They simulate the insurer’s optimal output responses to loss shocks, including output movements in underwriting coverage and external capital, to explore the source of unpredictable underwriting cycles through linear quadratic approximation in the model economy.

Findings

The authors find that the effect of loss shocks on the insurer’s cash flows could spread out and amplify over time because of the dynamic interaction between its underwriting capability and ability to raise external capital. This dynamic interaction can generate a non-cyclical pattern of changes in underwriting coverage and access to external capital in the benchmark economy. Applied to different experimental economies, the simulation results reveal that the determinants of the level of output fluctuations include the size of loss shocks, the sensitivity of capital market to loss shocks and the tightness of capital market.

Originality/value

To the best of the authors’ knowledge, there has been no attempt to study insurance output cyclicality with a dynamic cash flow model based upon the real business cycle literature, in which the dynamic interaction between underwriting and access to external capital because of loss shocks has an amplifying effect on output markets. This paper contributes to the current body of research by being able to simulate and show the insurance output dynamics resulting from the amplifying effect under capacity constraints.

Details

The Journal of Risk Finance, vol. 20 no. 1
Type: Research Article
ISSN: 1526-5943

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Article
Publication date: 4 September 2017

Jian-jun Yuan, Weiwei Wan, Xiajun Fu, Shuai Wang and Ning Wang

This paper aims to propose a novel method to identify the parameters of robotic manipulators using the torque exerted by the robot joint motors (measured by current sensors).

Abstract

Purpose

This paper aims to propose a novel method to identify the parameters of robotic manipulators using the torque exerted by the robot joint motors (measured by current sensors).

Design/methodology/approach

Previous studies used additional sensors like force sensor and inertia measurement unit, or additional payload mounted on the end-effector to perform parameter identification. The settings of these previous works were complicated. They could only identify part of the parameters. This paper uses the torque exerted by each joint while performing Fourier periodic excited trajectories. It divides the parameters into a linear part and a non-linear part, and uses linear least square (LLS) parameter estimation and dual-swarm-based particle swarm optimization (DPso) to compute the linear and non-linear parts, respectively.

Findings

The settings are simpler and can identify the dynamic parameters, the viscous friction coefficients and the Coulomb friction coefficients of two joints at the same time. A SIASUN 7-Axis Flexible Robot is used to experimentally validate the proposal. Comparison between the predicted torque values and ground-truth values of the joints confirms the effectiveness of the method.

Originality/value

The proposed method identifies two joints at the same time with satisfying precision and high efficiency. The identification errors of joints do not accumulate.

Details

Assembly Automation, vol. 37 no. 4
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 19 March 2021

Zhenyu Lu and Ning Wang

Dynamic movement primitives (DMPs) is a general robotic skill learning from demonstration method, but it is usually used for single robotic manipulation. For cloud-based…

Abstract

Purpose

Dynamic movement primitives (DMPs) is a general robotic skill learning from demonstration method, but it is usually used for single robotic manipulation. For cloud-based robotic skill learning, the authors consider trajectories/skills changed by the environment, rebuild the DMPs model and propose a new DMPs-based skill learning framework removing the influence of the changing environment.

Design/methodology/approach

The authors proposed methods for two obstacle avoidance scenes: point obstacle and non-point obstacle. For the case with point obstacles, an accelerating term is added to the original DMPs function. The unknown parameters in this term are estimated by interactive identification and fitting step of the forcing function. Then a pure skill despising the influence of obstacles is achieved. Using identified parameters, the skill can be applied to new tasks with obstacles. For the non-point obstacle case, a space matching method is proposed by building a matching function from the universal space without obstacle to the space condensed by obstacles. Then the original trajectory will change along with transformation of the space to get a general trajectory for the new environment.

Findings

The proposed two methods are certified by two experiments, one of which is taken based on Omni joystick to record operator’s manipulation motions. Results show that the learned skills allow robots to execute tasks such as autonomous assembling in a new environment.

Originality/value

This is a new innovation for DMPs-based cloud robotic skill learning from multi-scene tasks and generalizing new skills following the changes of the environment.

Details

Assembly Automation, vol. 41 no. 3
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 5 April 2021

Shifeng Lin and Ning Wang

In multi-robot cooperation, the cloud can share sensor data, which can help robots better perceive the environment. For cloud robotics, robot grasping is an important…

Abstract

Purpose

In multi-robot cooperation, the cloud can share sensor data, which can help robots better perceive the environment. For cloud robotics, robot grasping is an important ability that must be mastered. Usually, the information source of grasping mainly comes from visual sensors. However, due to the uncertainty of the working environment, the information acquisition of the vision sensor may encounter the situation of being blocked by unknown objects. This paper aims to propose a solution to the problem in robot grasping when the vision sensor information is blocked by sharing the information of multi-vision sensors in the cloud.

Design/methodology/approach

First, the random sampling consensus algorithm and principal component analysis (PCA) algorithms are used to detect the desktop range. Then, the minimum bounding rectangle of the occlusion area is obtained by the PCA algorithm. The candidate camera view range is obtained by plane segmentation. Then the candidate camera view range is combined with the manipulator workspace to obtain the camera posture and drive the arm to take pictures of the desktop occlusion area. Finally, the Gaussian mixture model (GMM) is used to approximate the shape of the object projection and for every single Gaussian model, the grabbing rectangle is generated and evaluated to get the most suitable one.

Findings

In this paper, a variety of cloud robotic being blocked are tested. Experimental results show that the proposed algorithm can capture the image of the occluded desktop and grab the objects in the occluded area successfully.

Originality/value

In the existing work, there are few research studies on using active multi-sensor to solve the occlusion problem. This paper presents a new solution to the occlusion problem. The proposed method can be applied to the multi-cloud robotics working environment through cloud sharing, which helps the robot to perceive the environment better. In addition, this paper proposes a method to obtain the object-grabbing rectangle based on GMM shape approximation of point cloud projection. Experiments show that the proposed methods can work well.

Details

Assembly Automation, vol. 41 no. 3
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 18 May 2021

Ning Wang, Haitao Zhang and Huizhong Xiong

In order to unravel the evolution of microstructure characteristics and the change of mechanical properties of bituminous mixture in the freezing and thawing environment…

Abstract

Purpose

In order to unravel the evolution of microstructure characteristics and the change of mechanical properties of bituminous mixture in the freezing and thawing environment in cold region, this study starts from macroscopic experiments and analyzes the changes in mechanical properties of asphalt mixtures before and after freezing and thawing in detail. On this basis, the displacement of key particles in the structure of asphalt mixture under the action of external forces (before and after freezing and thawing) is simulated through the combination macroscopic and microscopic methods.

Design/methodology/approach

The climate in China exhibits high complexity and diversity, divided into five zones based on the temperature difference from south to north. Considering that the significant effect of geography and natural climate on the design, construction and maintenance of asphalt pavement, the criterion for the road construction at different areas should be highly different.

Findings

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.

Originality/value

The results show that the mechanical properties of asphalt mixture greatly decrease due to the influence of freeze-thaw, and the displacement of key particles in the structure of asphalt mixture (several representative particle sizes were selected through experiments) is obviously observed because of the action of external force. By analyzing the variation of several key particle sizes after freezing-thawing cycle, the gradation standard of asphalt mixture aggregate suitable for cold area was obtained. The research results have certain theoretical and practical value for the design and application of asphalt mixture in cold area.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 24 January 2020

Xiujuan Tian, Manhua Wu, Lin Ma and Ning Wang

The purpose of this paper is to empirically investigate the effect of rural finance on industrial integration of rural primary, secondary and tertiary industries.

Abstract

Purpose

The purpose of this paper is to empirically investigate the effect of rural finance on industrial integration of rural primary, secondary and tertiary industries.

Design/methodology/approach

Using household-level data collected by Third National Agricultural Census and the provincial-level data collected from Wind database, the authors estimated the impacts of rural finance on rural industrial integration using Logit and Probit regression models. Further, the authors examined how the effect of rural finance varies with the age and education of householders, and with household and provincial characteristics by investigating the moderating effect.

Findings

The findings show that rural finance has a significant and positive effect on promoting farmers’ participation in new agricultural management organizations. This effect is more obvious in families whose householders are 40–50 years old, or families that have more educated members. This is because the middle-aged or educated people are more willing to accept and take part in industrial integration. The results further indicate that rural finance has a greater effect on industrial integration in provinces with a high degree of marketization, and in provinces with the high output value of industries and services in agricultural intermediate input.

Originality/value

The authors investigated the impact of rural finance on rural industrial integration empirically, and this topic is rarely covered before. The findings of this study also enrich the literature on financial development and economic growth as well as provide policy suggestions on how to promote rural industrial integration.

Details

China Agricultural Economic Review, vol. 12 no. 2
Type: Research Article
ISSN: 1756-137X

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Article
Publication date: 11 April 2016

Qiyin Lin, Zhengying Wei, Ning Wang and Yubin Zhang

The purpose of this paper is to study the influences of recess configurations on the performances of high-speed hybrid journal bearing. Hybrid journal bearing earns…

Abstract

Purpose

The purpose of this paper is to study the influences of recess configurations on the performances of high-speed hybrid journal bearing. Hybrid journal bearing earns increasing attention in high-speed machine tool spindle owing to its intrinsic outstanding performances of low temperature rise and high stability.

Design/methodology/approach

To investigate the coupled effects of temperature, turbulence and the interaction between lubricant and journal/bearing bush, a thermal fluid-structure interaction approach is presented and validated by the experimental results.

Findings

Ladder-type recess has excellent tribological characteristics in decreasing temperature rise, improving stability and inhibiting cavitation, which are all beneficial to improve the performances of high-speed spindle system.

Originality/value

This work can be a valuable guide for the future high-speed hybrid journal bearing design.

Details

Industrial Lubrication and Tribology, vol. 68 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Book part
Publication date: 26 June 2013

Yee-Ching Lilian Chan

This study looks at board governance in Ontario hospitals.

Abstract

Purpose

This study looks at board governance in Ontario hospitals.

Methodology/approach

We conducted a research of the hospitals’ websites and a survey of board directors to study the board structure and examine governance practice in Ontario hospitals.

Findings

The findings suggest that the board structure and process in Ontario hospitals are in compliance with Accreditation Canada’s Governance Standards, and such administrative controls are appropriate. Ontario hospital boards, in general, have fulfilled their key functions of governance in terms of working as an effective board; developing a clear direction; supporting the organization to achieve its mandate; maintaining positive relationships with external stakeholders; and being accountable and achieving sustainable results. Building knowledge through information is an area where improvement is needed.

Research implications

Ontario hospitals have implemented appropriate administrative controls in terms of board composition and committee structure. The results of a survey of 99 board directors from over 25 hospitals suggest that directors, in general, have a good understanding of their governance role and relationship with senior management as well as the government. The findings are also supportive of good governance practice where executives manage and nonexecutive directors monitor the performance of the executives. According to the respondents, Ontario’s hospital boards are actively involved in setting the mission, strategic goals and objectives of their organizations, and they take appropriate steps to ensure that risk management, client safety, and quality improvements are incorporated in their governance and strategic planning process. In order to discharge their fiduciary duty effectively, respondents would like to have more information from different sources. This is an area where management accounting professionals can become involved such that relevant information from a variety of sources, especially external sources, are provided to board directors for decision making.

Practical implications

Ontario’s hospital sector has undertaken initiatives through research and publications to promote good governance practice. Such leadership is critical to ensure that directors have the competence and skills to discharge their duties and responsibilities diligently. Hospital boards should focus on renewal while ensuring that board directors are equipped for the challenging task of governing through professional development and continuing education.

Limitations and future research

Limitations related to the use of questionnaire applies to this research study. Self-selection bias and low response rate limit the generalizability of the findings. Future research can examine the behavior of directors in the boardroom and the impact of governance variables on hospital performance, such as quality of care and patient safety.

Details

Advances in Management Accounting
Type: Book
ISBN: 978-1-78190-842-6

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