Search results
1 – 4 of 4Cristian Alejandro Vergara, Gianni Borghesan, Erwin Aertbeliën and Joris De Schutter
The purpose of this paper is to develop a control strategy for human–robot collaborative manipulation tasks that can deal with proximity signals from 373 interconnected cells of…
Abstract
Purpose
The purpose of this paper is to develop a control strategy for human–robot collaborative manipulation tasks that can deal with proximity signals from 373 interconnected cells of an artificial skin.
Design/methodology/approach
The robot and the operator accomplish an industrial task while interacting in a shared workspace. The robot controller detects and avoids collisions based on the information from the artificial skin. Conflicting constraints can be handled by prioritizing between hard and soft constraints or by weighing the different constraints.
Findings
Weak soft constraints (low weight) are specified to command the robot to move along a nominal path with constant velocity. Stronger soft constraints (higher weight) prevent collisions by means of either moving the end effector backward along the path or circumventing an obstacle. The proposed approach is validated experimentally.
Originality/value
As a first contribution, this paper proposes a discrete optimization algorithm activates an a priori selected maximum number of cells. The algorithm selects the appropriate distribution based on the amplitude of each signal and the spatial distribution of the proximity measurements. A second contribution is the specification of a human–robot collaborative application as an optimization problem using eTaSL (expression graph-based task specification language), which provides reactive control.
Details
Keywords
This paper explores the paradigm of international development that has persisted for the past five decades, and asks whether a fresh approach is needed – one that builds on the…
Abstract
Purpose
This paper explores the paradigm of international development that has persisted for the past five decades, and asks whether a fresh approach is needed – one that builds on the developmental potential of the corporate sector, not just on donor aid.
Design/methodology/approach
This article explores both how corporations contribute to development and also the challenges in incorporating them into the wider processes of international development. This is achieved through the examination of two key sets of literature. The first is that regarding the effectiveness of the existing approach to international development. The second, smaller but growing, explores the impact that the corporate sector has had on raising countries out of poverty.
Findings
This paper finds that despite the cost and effort, most developing countries remain just that – developing. Where countries have developed, there is strong evidence to suggest that this has been the result, not of international aid, but of a thriving corporate sector. Yet companies remain outside the prevailing development paradigm, and their contribution to lifting countries out of poverty remains poorly understood. This paper makes a number of recommendations in relation to further research that is needed, and also policy approaches that need to be explored.
Research limitations/implications
It is apparent from this paper that more and detailed scholarly work is needed to improve further our understanding of how companies contribute to development.
Practical implications
For policy makers this paper demonstrates an urgent need to develop better and more thorough‐going processes to engage with the corporate sector.
Originality/value
The role that companies play in international development remains under‐explored. This paper is therefore a novel contribution to this debate, and one that has significant implications for both the academic and policy communities.
Details
Keywords
Md. Hazrat Ali, Gani Issayev, Essam Shehab and Shoaib Sarfraz
In recent years, 3D printing technologies have been widely used in the construction industry. 3D printing in construction is very attractive because of its capability of process…
Abstract
Purpose
In recent years, 3D printing technologies have been widely used in the construction industry. 3D printing in construction is very attractive because of its capability of process automation and the possibility of saving labor, waste materials, construction time and hazardous procedures for humans. Significant researches were conducted to identify the performance of the materials, while some researches focused on the development of novel techniques and methods, such as building information modeling. This paper aims to provide a detailed overview of the state-of-the-art of currently used 3D printing technologies in the construction areas and global acceptance in its applications.
Design/methodology/approach
The working principle of additive manufacturing in construction engineering (CE) is presented in terms of structural design, materials used and theoretical background of the leading technologies that are used to construct buildings and structures as well as their distinctive features.
Findings
The trends of 3D printing processes in CE are very promising, as well as the development of novel materials, will gain further momentum. The findings also indicate that the digital twin (DT) in construction technology would bring the industry a step forward toward achieving the goal of Industry 5.0.
Originality/value
This review highlights the prospects of digital manufacturing and the DT in construction engineering. It also indicates the future research direction of 3D printing in various constriction sectors.
Details
Keywords
Guanghui Liu, Qiang Li, Lijin Fang, Bing Han and Hualiang Zhang
The purpose of this paper is to propose a new joint friction model, which can accurately model the real friction, especially in cases with sudden changes in the motion direction…
Abstract
Purpose
The purpose of this paper is to propose a new joint friction model, which can accurately model the real friction, especially in cases with sudden changes in the motion direction. The identification and sensor-less control algorithm are investigated to verify the validity of this model.
Design/methodology/approach
The proposed friction model is nonlinear and it considers the angular displacement and angular velocity of the joint as a secondary compensation for identification. In the present study, the authors design a pipeline – including a manually designed excitation trajectory, a weighted least squares algorithm for identifying the dynamic parameters and a hand guiding controller for the arm’s direct teaching.
Findings
Compared with the conventional joint friction model, the proposed method can effectively predict friction factors during the dynamic motion of the arm. Then friction parameters are quantitatively obtained and compared with the proposed friction model and the conventional friction model indirectly. It is found that the average root mean square error of predicted six joints in the proposed method decreases by more than 54%. The arm’s force control with the full torque using the estimated dynamic parameters is qualitatively studied. It is concluded that a light-weight industrial robot can be dragged smoothly by the hand guiding.
Practical implications
In the present study, a systematic pipeline is proposed for identifying and controlling an industrial arm. The whole procedure has been verified in a commercial six DOF industrial arm. Based on the conducted experiment, it is found that the proposed approach is more accurate in comparison with conventional methods. A hand-guiding demo also illustrates that the proposed approach can provide the industrial arm with the full torque compensation. This essential functionality is widely required in many industrial arms such as kinaesthetic teaching.
Originality/value
First, a new friction model is proposed. Based on this model, identifying the dynamic parameter is carried out to obtain a set of model parameters of an industrial arm. Finally, a smooth hand guiding control is demonstrated based on the proposed dynamic model.
Details