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1 – 10 of over 39000Abstract
Purpose
The purpose of this paper is to propose a two-degrees-of-freedom wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring, in order to improve the robot’s athletic ability, load capacity and rigidity, and to ensure the coordination of multi-modal motion.
Design/methodology/approach
First, based on the rotation transformation matrix and closed-loop constraint equation of the parallel trunk joint mechanism, the mathematical model of its inverse position solution is constructed. Then, the Jacobian matrix of velocity and acceleration is derived by time derivative method. On this basis, the stiffness matrix of the parallel trunk joint mechanism is derived on the basis of the principle of virtual work and combined with the deformation effect of the rope driving pair and the spring elastic restraint pair. Then, the eigenvalue distribution of the stiffness matrix and the global stiffness performance index are used as the stiffness evaluation index of the mechanism. In addition, the performance index of athletic dexterity is analyzed. Finally, the distribution map of kinematic dexterity and stiffness is drawn in the workspace by numerical simulation, and the influence of the introduced spring on the stiffness distribution of the parallel trunk joint mechanism is compared and analyzed. It is concluded that the stiffness in the specific direction of the parallel trunk joint mechanism can be improved, and the stiffness distribution can be improved by adjusting the spring elastic structure parameters of the rope-driven branch chain.
Findings
Studies have shown that the wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring has a great kinematic dexterity, load-carrying capacity and stiffness performance.
Research limitations/implications
The soft-mixed structure is not mature, and there are few new materials for the soft-mixed mixture; the rope and the rigid structure are driven together with a large amount of friction and hindrance factors, etc.
Practical implications
It ensures that the multi-motion mode hexapod mobile robot can meet the requirement of sufficient different stiffness for different motion postures through the parallel trunk joint mechanism, and it ensures that the multi-motion mode hexapod mobile robot in multi-motion mode can meet the performance requirement of global stiffness change at different pose points of different motion postures through the parallel trunk joint mechanism.
Social implications
The trunk structure is a very critical mechanism for animals. Animals in the movement to achieve smooth climbing, overturning and other different postures, such as centipede, starfish, giant salamander and other multi-legged animals, not only rely on the unique leg mechanism, but also must have a unique trunk joint mechanism. Based on the cooperation of these two mechanisms, the animal can achieve a stable, flexible and flexible variety of motion characteristics. Therefore, the trunk joint mechanism has an important significance for the coordinated movement of the whole body of the multi-sport mode mobile robot (Huang Hu-lin, 2016).
Originality/value
In this paper, based on the idea of combining rigid parallel mechanism with wire-driven mechanism, a trunk mechanism is designed, which is composed of four spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism in series. Its spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism can make the multi-motion mode mobile robot have better load capacity, mobility and stiffness performance (Qi-zhi et al., 2018; Cong-hao et al., 2018), thus improving the environmental adaptability and reliability of the multi-motion mode mobile robot.
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S. Arzanpour, J. Fung, J.K. Mills and W.L. Cleghorn
To design a reconfigureable flexible fixture for the assembly of a set of sheet metal automotive body parts. Reconfigureable fixturing permits different parts to be grasped for…
Abstract
Purpose
To design a reconfigureable flexible fixture for the assembly of a set of sheet metal automotive body parts. Reconfigureable fixturing permits different parts to be grasped for assembly by a fixture without the need to conduct costly redesign and fabrication of hardware fixtures, which is an industry standard in widespread use in industry. While somewhat more complex than fixtures in current use, reconfigureable fixtures provide one solution to the problem of costly redesign of fixtures due to changes in dimensions, or geometry of parts to be assembled.
Design/methodology/approach
We propose a novel reconfigureable fixture for robotic assembly of a number of different parts. Motivated by the marine organism, O. vulgaris, commonly referred to as an octopus, which grasps different objects or prey using suction cups, the proposed fixture has three fingers, each equipped with a suction cup, to facilitate the grasping process and increase grasp flexibility. Using this design approach, the fixture is sufficiently general in design to grasp several different parts. To position the suction cups located on the flexible fixture, two linkage‐based mechanisms are employed. Pneumatic cylinders and electric motors are used as actuators. A prototype flexible fixture has been built and experimental results with this prototype confirm the effectiveness of the proposed flexible fixture. Software has been developed to calculate the relative positions and angles in the mechanism as required for reconfiguration.
Findings
The proposed reconfigureable fixture, used as an end‐of‐arm tool, permits each of a set of four sheet metal parts to be successfully grasped permitting assembly of these four components, in a robotic assembly work cell.
Research limitations/implications
The proposed flexible fixture is a simple proof‐of‐concept device that is suitable for a laboratory setting. We do not consider part localization of parts when grasped by the reconfigureable fixture.
Practical implications
Assembly operations, in industrial manufacturing operations, are typically heavily reliant on hardware fixtures devices to orient and clamp parts together during assembly operations. While of great importance in such operations, hardware fixtures are very costly to design and build. Further, fixtures are designed for use with parts of specific dimensions and geometry, hence cannot be used to grasp or orient parts with even very small differences in dimensions or geometry. Typically, if parts with different dimensions or geometry are to be assembled, new hardware fixtures must be designed and manufactured to grasp and orient these parts. This lack of flexibility leads to substantial manufacturing costs associated with fixturing. Reconfigureable fixtures permit parts with different geometries to be grasped and oriented for assembly.
Originality/value
Reconfigureable fixtures for use in the automotive manufacturing sector is an important development due to the highly competitive nature of this industry. Rapid introduction of new models of vehicles is greatly facilitated through the use of reconfigureable fixtures which can be reprogrammed to grasp parts of different geometries required for new vehicle models.
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Nielen Stander and Erwin Stein
Using examples of flexible mechanisms, demonstrates that while the Newmark method is unstable for nonlinear dynamics, time step refinement could in some cases lead to even earlier…
Abstract
Using examples of flexible mechanisms, demonstrates that while the Newmark method is unstable for nonlinear dynamics, time step refinement could in some cases lead to even earlier onset of instability in the form of a blown‐up response. As a remedy, develops a plane finite beam element based on the Simo‐Vu Quoc formulation for dynamics and integrates it with an energy‐conserving midpoint time‐stepping rule for solving problems in nonlinear dynamics. Shows that this combination produces a consistently stable and accurate dynamic analysis method even for large time steps.
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Abstract
Purpose
The purpose of this paper is to provide an accurate dynamic model for the flexible cable capture mechanism and to analyze the dynamic characteristics in the capturing process.
Design/methodology/approach
The absolute nodal coordinate formulation (ANCF) that based on the continuum mechanics approach is applied in the capture task using flexible cables. An ANCF cable element in which axial and bending strain energy are taken into account is presented to model the flexible cables. The generalized coordinates of ANCF are absolute displacements and slopes and make no small deformation assumptions; therefore, this element has a remarkable superiority in the large rotation and deformation analysis of flexible cables compared to the conventional floating frame of reference formulation (FFRF). The mass matrix of the cable element is constant, which will reduce the degree of non-linearity of the dynamic equations. The contact force between the steel cables and capture rod is calculated by the non-linear contact dynamic model, in which material and geometry properties of contact bodies are considered.
Findings
The stress distribution of steel cables is investigated in the numerical studies which show that the closer to the ends of the cable, the larger axial forces and smaller bending moments they will be. The reduction of grasping velocity will lead to a decrease in the contact force and the oversize peak value of contact force is more likely to be avoided when reducing the elastic modulus of steel cables to obtain a greater soft capture capability.
Practical implications
The work shows a practical possibility to improve modeling accuracy of the capture mechanism. Results of the analyses can provide references for the design and analysis of the capture task.
Originality/value
The ANCF is first used in the analysis of the capture task with flexible cables, and some useful results which have not been published before are obtained.
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Woongsun Jeon, Inho Kim, Jungwan Park and Hyunseok Yang
The purpose of this paper is to propose a high‐mobility in‐pipe robot platform and its navigation strategy for navigating in T‐branch pipes efficiently.
Abstract
Purpose
The purpose of this paper is to propose a high‐mobility in‐pipe robot platform and its navigation strategy for navigating in T‐branch pipes efficiently.
Design/methodology/approach
For high mobility, this robot is developed based on inchworm locomotion. An extensor mechanism with flexible links and clamper mechanisms enable the robot to conduct both steering and inchworm locomotion. The locomotion of the robot is modeled based on a pseudo‐rigid‐body model. From the developed model, this paper introduces a navigation strategy based on defining relay points and generating a path from a main pipe to a T‐branch pipe.
Findings
With this navigation strategy, the robot can avoid collisions and enter T‐branch pipes effectively. The path generation algorithm is verified by experiment. In addition, both the navigation strategy and mobility of the robot are demonstrated by experiments conducted in a commercial pipe configuration.
Originality/value
This paper describes the mechanism of an inchworm‐type in‐pipe robot that is able to steer and adapt to pipe diameter changes. This paper also describes navigation strategy that enables a robot to avoid collisions and enter T‐branch pipes effectively. This research will help the construction of a fully autonomous in‐pipe robot that can navigate through various types of pipes.
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The purpose of this paper is to investigate employee perceptions of the flexibility they utilize or have available to them in an NHS Trust and relate these perceptions to the…
Abstract
Purpose
The purpose of this paper is to investigate employee perceptions of the flexibility they utilize or have available to them in an NHS Trust and relate these perceptions to the concept of control.
Design/methodology/approach
The paper adopts a constructivist approach and uses semi‐structured interviews, allowing employees, in their own way, to explain what flexibility policies, and practice mean to them. The paper conducted 43 interviews and one focus group across five directorates, to include a range of staff levels and job types.
Findings
The findings in this paper show that informal rather than formal flexibility was more widely used and valued; and that, although staff needed to be proactive to access formal flexibility, some staff did not see formal flexibility as relevant to themselves; and informal flexibility generated an increased sense of employee responsibility. Uses the perspective of employee control over their working lives, in order to interpret the impact of flexible working.
Research limitations/implications
The paper shows that these findings may be context‐specific, and further investigation of informal flexible working is needed in different settings.
Practical implications
This paper shows that organizations need to communicate flexibility well, and train their managers' adequately but, critically, they need to understand what different forms of flexibility mean to employees, and how they are valued.
Originality/value
The paper shows the prevalence and value of informal flexible working, and its potential. Uses the concept of control to explain why different individuals value different forms of flexible working differentially.
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Guoda Chen, Huafeng Yang, Huiqiang Cao, Shiming Ji, Xi Zeng and Qian Wang
For the climbing rod object with large diameter variation and the need of obstacle crossing, this paper aims to propose a new embracing-type climbing robot named as EVOC-I robot.
Abstract
Purpose
For the climbing rod object with large diameter variation and the need of obstacle crossing, this paper aims to propose a new embracing-type climbing robot named as EVOC-I robot.
Design/methodology/approach
The design philosophy and structural scheme are introduced. The kinematic analysis of embracing and telescoping mechanisms is carried out to provide the theoretical foundation for the effective climbing of the robot. Based on the prototype robot, three preliminary experiments are carried out to verify the effectiveness of the designed robot.
Findings
The theoretical and experimental analyses have verified the reasonability and effectiveness of the proposed robot design.
Research limitations/implications
As the preliminary study, the prototype still need a lot of improvement. The experimental verification is also limited. Future work will focus on improving the design and increasing the theoretical analysis, especially increasing experimental study and designing the next generation of the rod climbing robot.
Practical implications
The designed climbing robot can be used for climbing the rod with variation diameter and flange obstacle, especially the lightening rod in the transformer substation.
Originality/value
The paper designs a new climbing robot that integrates the ability of large variation diameter adaptation and obstacle crossing.
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Keywords
The concept of “routines” is used to classify diverse enterprise application systems (EAS) into a framework. The purpose of this paper is to discuss the theoretical underpinnings…
Abstract
Purpose
The concept of “routines” is used to classify diverse enterprise application systems (EAS) into a framework. The purpose of this paper is to discuss the theoretical underpinnings and EAS falling into each of the framework quadrants. The framework provides a guideline for firms to meet their EAS‐organizational alignment challenges.
Design/methodology/approach
The EAS‐organizational alignment framework in this paper is developed through a synthesis of literature. The framework links EAS and organizational routines according to intra‐ and inter‐levels of organizational analysis and inflexible and flexible governance mechanisms.
Findings
The findings suggest that a fit between EAS routines and organizational routines leads to successful EAS deployments and hence improved business performance.
Research limitations/implications
The findings provide researchers with reasons to incorporate routines into existing research models to better explain EAS‐organizational alignment. The next step is to empirically validate the EAS‐organizational alignment framework.
Practical implications
Firms can gain an understanding of how EAS routines and organizational routines can be manipulated to positively influence EAS‐organizational alignment and hence increase business performance. Firms can use routines as strategic tools for adoption and successful deployment of EAS across their global operations.
Originality/value
The paper's findings provide a perspective, different from past research, on our understanding of EAS‐organizational alignment and offer valuable guidance for future research in this area.
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Huan Liu, Rui Wang, Junyao Wang, Xingyu Chen, Yunpeng Li, Bowen Cui, Tianhong Lang and Weihua Zhu
Flexible pressure sensor arrays have promising applications in analog haptics, reconfiguration of sensory functions, artificial intelligence, wearable devices and human-computer…
Abstract
Purpose
Flexible pressure sensor arrays have promising applications in analog haptics, reconfiguration of sensory functions, artificial intelligence, wearable devices and human-computer interaction. The force disturbance generated by the connecting material between the sensor array units will reduce the detection accuracy of the unit. The purpose of this paper is to propose a flexible pressure sensor with interference immunity capability. A C-type bridge flexible piezoelectric structure is used to improve the pressure perturbation. The interference immunity capability of the sensor has been improved.
Design/methodology/approach
In this paper, a C-type pressure sensor array structure by rapid injection moulding is manufactured through the positive piezoelectric effect of a piezoelectric material. The feasibility of C-type interference immunity structure in a flexible sensor array is verified by further analysis and experiment. A flexible pressure sensor array with C-type interference immunity structure has been proposed.
Findings
In this paper, we present the results of the perturbation experiment results of the C-type pressure sensor array, showing that the perturbation error is less than 8%. The test of the flexible sensor array show that the sensor can identify the curved angle of up to 120 °, and the output sensitivity of the sensor in the horizontal state reaches 0.12 V/N, and the sensor can withstand the pressure of 80 N. The flexible sensor can work stably in the stretch rate range of 0–8.6% and the stretch length range of 0–6 mm.
Originality/value
In this paper, C-type pressure sensor array structure is fabricated by rapid injection moulding for the first time. The research in this paper can effectively reduce the disturbance of input pressure on the sensor’s internal array and improve the output accuracy. The sensor can intuitively reflect the number of fingers sliding on the sensor by the order in which the maximum voltage appears. Due to the strong interference immunity capability and flexibility of the flexible sensor array mechanism, it has a broad application prospect in the practical fields of haptic simulation, perceptual function reconstruction, artificial intelligence, wearable devices and human–computer interaction.
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The purpose of this paper is to address the key issues, how organizational networks influence the strategic business performance (SBP) through the mediating role of organizational…
Abstract
Purpose
The purpose of this paper is to address the key issues, how organizational networks influence the strategic business performance (SBP) through the mediating role of organizational flexibility, and the moderating role of entrepreneurial orientation (EO). Contextualizing small and medium enterprises in developing countries, the authors have developed and tested a theoretical model of SBP to provide a framework for analyzing its major antecedents.
Design/methodology/approach
This research used a quantitative approach with cross-sectional data. The authors used correlation, regression and Baron and Kenny Approach (Causal Step Approach) for analyzing the data collected from 737 CEOs/MDs/owners of different small and medium enterprises to test the theoretical model developed for this study.
Findings
Findings revealed that organizational flexibility mediates the relationship between organizational network and SBP. Furthermore, stronger EO strengthens the relationship between organizational flexibility and SBP.
Originality/value
This study contributes in two ways: first, it provides empirical evidences that how to flourish the mechanism of SBP in SMEs. Second, this work contributes to understand the effects of organizational networks, flexibility and EO on SBP.
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