The repeatability positioning analysis of the industrial robot arm

2014 ◽  
Vol 34 (3) ◽  
pp. 285-295 ◽  
Author(s):  
Rafał Kluz ◽  
Tomasz Trzepieciński
Keyword(s):  
Empirical Distribution ◽  
Industrial Robot ◽  
Random Variable ◽  
Design Stage ◽  
Assembly Process ◽  
Positioning Error ◽  
Robot Arm ◽  
Optimal Position ◽  
Content Type ◽  
Wide Range

Purpose – The purpose of the following work was to work out the dependency to allow for the determination of the repeatability positioning error value of the robot at any given point in its workspace, without the necessity of conducting time-consuming measurements while routing a precise surface of repeatability positioning. Design/methodology/approach – The presented dependency permits for the possibility to determine, even at the planning phase, the optimal connection point in the workspace, ensuring the best parameters for the process of machine assembly, without needless overestimation of precision of the utilized equipment. To solve the task the sequential quadratic programming (SQP) method implemented in the MATLAB(R) environment was used. To verify the hypothesis of the compatibility of the empirical distribution with the hypothetical distribution of the robot’s positioning error, the Kolmogorov test was used. Findings – In this paper, it has been demonstrated theoretically and experimentally that the industrial robot accuracy can vary over a very wide range in the workspace. This provides an additional opportunity to increase reliability of the assembly process through the appropriate choice of the point of parts joining. The methodology presented here allows the designer of assembly workstations to rapidly estimate the repeatability of robot positioning and to allocate at the design stage of assembly process the optimal position in the robot workspace to ensure the required precision, without unnecessarily high accuracy of equipment used and, therefore, without inflated costs. Originality/value – An alternative solution to the stated problem can be the proposed method for determining the robot’s positioning errors, requiring a much smaller amount of measurements to be taken that would be necessary to determine the parameters of the random variable errors of the joint coordinates of the robot and for their verification by the repeatability of positioning in randomly selected points in the workspace. Additionally discussed in the study, the methodology of identifying connection place was designed for typical combinations of machine parts, most frequently encountered in assembly process and was taken into account, typical limitations occurring in actual manufacturing conditions.

scholarly journals Digital information technologies for prevention through design (PtD): a literature review and directions for future research

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Karim Farghaly ◽  
William Collinge ◽  
Mojgan Hadi Mosleh ◽  
Patrick Manu ◽  
Clara Man Cheung
Keyword(s):  
Literature Review ◽  
Rapid Development ◽  
Digital Technologies ◽  
Construction Safety ◽  
Design Stage ◽  
Future Research ◽  
Digital Information ◽  
Content Type ◽  
Wide Range ◽  
Prevention Through Design

Purpose With the rapid development of digital information and modelling software applications for construction, questions have arisen about their impact on construction safety. Meanwhile, recognition that designers can help reduce risks involved in construction, operation and maintenance via a prevention through design (PtD) approach (also known as design for safety) highlights the significance of digital technologies and tools to PtD. Thus, this paper aims to provide a systematic review of a wide range of digital technologies for enhancing PtD. Design/methodology/approach A five-stage systematic literature review with coding and synthesis of findings is presented. The review covers journal articles published between 2000 and 2020 related to the applications of various digital technologies, such as building information modelling (BIM), 4D, databases, ontologies, serious games, virtual reality and augmented reality, for addressing safety issues during the design phase in construction. Findings Analysis of the articles yielded a categorisation of the digital applications for PtD into four main areas: knowledge-based systems; automatic rule checking; hazard visualization; and safety training for designers. The review also highlighted designers’ limited knowledge towards construction safety and the possibility to address this by using gaming environments for educating designers on safety management and using artificial intelligence for predicting hazards and risks during design stage in a BIM environment. Additionally, the review proposes other directions for future research to enhance the use of digital technologies for PtD. Originality/value This paper contextualises current digital technology applications for construction health and safety and enables future directions of research in the field to be identified and mapped out.

An innovative strategy to create equivalent elements for modelling assembly points in joined structures

2014 ◽  
Vol 31 (3) ◽  
pp. 453-466 ◽  
Author(s):  
Maxime Bérot ◽  
Julien Malrieu ◽  
François Bay
Keyword(s):  
Finite Element ◽  
Experimental Tests ◽  
Element Model ◽  
Design Stage ◽  
Computational Time ◽  
Assembly Process ◽  
Mechanical State ◽  
Complete Model ◽  
Content Type ◽  
Innovative Strategy

Purpose – Large structures (e.g. plane, bridge, etc.) often include several hundreds of assembly points. Structural computations often use over-simplistic approximations for these points; among others, they do not take into account the thermo-mechanical history due to the assembling process. Running computations with each assembly point modelled completely would require too much time to achieve a simulation. There is thus a need to create equivalent elements for assembly points in order to: take into account the mechanical state of the assembly point in the design stage – while reducing the computational time cost at the same time. This paper aims to discuss these issues. Design/methodology/approach – This paper introduces an innovative strategy based on a coupling procedure between a finite element tool for modelling the assembly process in order to access to the mechanical state of the assembly point and an optimisation algorithm, in order to identify the equivalent element parameters. Findings – The strategy has proven to be successful. A connector model easier to use and much faster than the complete model, has been obtained. Results obtained with this element are in good agreement with experimental tests in the case of multipoint assemblies and with the simulation results of the complete numerical model. Finally the connector model appears to be easier to use and much faster than the complete model, more difficult to model properly. Originality/value – The main innovative aspects of this strategy lie in the fact that the creation of this equivalent element is based on a complete numerical approach. The thermo-mechanical history due to the assembly process is considered – the element parameters are identified thanks to an evolution strategy based on the coupling between a finite element model and a zero-order minimisation algorithm.

Quantifying the complexity of subassemblies in a fully automated assembly system

2019 ◽  
Vol 39 (5) ◽  
pp. 803-812 ◽  
Author(s):  
Yicong Gao ◽  
Chuan He ◽  
Bing Zheng ◽  
Hao Zheng ◽  
Jianrong Tan
Keyword(s):  
Predictive Model ◽  
Design Stage ◽  
Design Solution ◽  
Assembly System ◽  
Assembly Process ◽  
Automated Assembly ◽  
Content Type ◽  
Dependency Matrix ◽  
Assembly Design ◽  
Main Challenge

Purpose Complexity is the main challenge for present and future manufacturers. Assembly complexity heavily affects a product’s final quality in the fully automated assembly system. This paper aims to propose a new method to assess the complexity of modern automated assembly system at the assembly design stage with respect to the characteristics of both manufacturing system and each single component to be mounted. Aiming at validating the predictive model, a regression model is additionally presented to estimate the statistic relationship between the real assembly defect rate and predicted complexity of the fully automated assembly system. Design/methodology/approach The research herein extends the S. N. Samy and H. A. ElMaraghy’s model and seeks to redefine the predictive model using fuzzy evaluation against a fully automated assembly process at the assembly design stages. As the evaluation based on the deterministic scale with accurate crisp number can hardly reflect the uncertainty of the judgement, fuzzy linguistic variables are used to measure the interaction among influence factors. A dependency matrix is proposed to estimate the assembly complexity with respect to the interactions between mechanic design, electric design and process factors and main functions of assembly system. Furthermore, a complexity attributes matrix of single part is presented, to map the relationship between all individual parts to be mounted and three major factors mentioned in the dependency matrix. Findings The new proposed model presents a formal quantification to predict assembly complexity. It clarifies that how the attributes of assembly system and product components complicate the assembly process and in turn influence the manufacturing performance. A center bolt valve in the camshaft of continue variable valve timing is used to demonstrate the application of the developed methodology in this study. Originality/value This paper presents a developed method, which can be used to improve the design solution of assembly concept and optimize the process flow with the least complexity.

Design and performance analysis of an industrial robot arm for robotic drilling process

2019 ◽  
Vol 46 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Longfei Sun ◽  
Fengyong Liang ◽  
Lijin Fang
Keyword(s):  
Control Method ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Ball Screw ◽  
Robotic Arm ◽  
Drilling Process ◽  
Robot Arm ◽  
Content Type ◽  
Robotic Drilling

Purpose The purpose of this paper is to present a robotic arm that can offer better stiffness than traditional industrial robots for improving the quality of holes in robotic drilling process. Design/methodology/approach The paper introduces a five-degree of freedom (DOF) robot, which consists of a waist, a big arm, a small arm and a wrist. The robotic wrist is composed of two DOFs of pitching and tilting. A parallelogram frame is used for robotic arms, and the arm is driven by a linear electric cylinder in the diagonal direction. Double screw nuts with preload are used in the ball screw to remove the reverse backlash. In addition, dual-motor drive is applied for each DOF in the waist and the wrist to apply anti-backlash control method for eliminating gear backlash. Findings The proposed robotic arm has the potential for improving robot stiffness because of its truss structure. The robot can offer better stiffness than industrial robots, which is beneficial to improve the quality of robotic drilling holes. Originality/value This paper includes the design of a five-DOF robot for robotic drilling tasks, and the stiffness modeling of the robot is presented and verified by the experiment. The robotic system can be used instead of traditional industrial robots for improving the hole quality to a certain extent.

scholarly journals On the Shifting Balance: the Case of Staphylococcus aureus CC398

mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Fernando Baquero
Keyword(s):  
Staphylococcus Aureus ◽  
Fitness Landscape ◽  
Peak Position ◽  
Bacterial Populations ◽  
Optimal Position ◽  
Content Type ◽  
Perfect Model ◽  
Wide Range ◽  
Shifting Balance ◽  
And Migration

ABSTRACT The recent study by L. Price et al. [mBio, 3(1):e00305-11, 2012] demonstrating the human origin of the livestock-associated CC398 Staphylococcus aureus provides an excellent example of how bacterial populations can explore a wide range of potential niches and acquire optimal adaptations for life in alternative hosts. The shifting balance theory proposed by Sewall Wright 80 years ago serves as a perfect model for understanding the observed facts: a possibly large CC398 population optimally positioned on the top of a fitness peak for living in a human host probably began evolving long ago by variation, drift, and migration, until it reached the low fitness edge of a neighboring alternative peak in the fitness landscape, one in a livestock host. The bacterial population then evolved again, moving uphill to reach a novel optimal “top of the peak” position in livestock. In the case of CC398, it is worrisome to think that it might readapt to human hosts without losing fitness in livestock; a double-host-adapted organism could certainly be in an optimal position for increasing its virulence and antibiotic resistance.

Adaptive arm motion generation of humanoid robot operating in dynamic environments

2014 ◽  
Vol 41 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Zulkifli Mohamed ◽  
Mitsuki Kitani ◽  
Genci Capi
Keyword(s):  
Humanoid Robot ◽  
Dynamic Environments ◽  
Robot Motion ◽  
Robot Arm ◽  
Objective Functions ◽  
Motion Generation ◽  
Content Type ◽  
Neural Controllers ◽  
Wide Range ◽  
Arm Motion

Purpose – The purpose of this paper is to compare the performance of the robot arm motion generated by neural controllers in simulated and real robot experiments. Design/methodology/approach – The arm motion generation is formulated as an optimization problem. The neural controllers generate the robot arm motion in dynamic environments optimizing three different objective functions; minimum execution time, minimum distance and minimum acceleration. In addition, the robot motion generation in the presence of obstacles is also considered. Findings – The robot is able to adapt its arm motion generation based on the specific task, reaching the goal position in simulated and experimental tests. The same neural controller can be employed to generate the robot motion for a wide range of initial and goal positions. Research limitations/implications – The motion generated yield good results in both simulation and experimental environments. Practical implications – The robot motion is generated based on three different objective functions that are simultaneously optimized. Therefore, the humanoid robot can perform a wide range of tasks in real-life environments, by selecting the appropriate motion. Originality/value – A new method for adaptive arm motion generation of a mobile humanoid robot operating in dynamic human and industrial environments.

scholarly journals Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

2015 ◽  
Vol 81 (7) ◽  
pp. 2481-2488 ◽  
Author(s):  
Volker Winstel ◽  
Petra Kühner ◽  
Bernhard Krismer ◽  
Andreas Peschel ◽  
Holger Rohde
Keyword(s):  
Plasmid Dna ◽  
Genetic Manipulation ◽  
Current Knowledge ◽  
Virulence Determinants ◽  
Coagulase Negative Staphylococci ◽  
Reliable Technique ◽  
Content Type ◽  
Research Activities ◽  
Wide Range ◽  
Genetic Barriers

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

scholarly journals A broadbanded pressure differential wave energy converter based on dielectric elastomer generators

2021 ◽  
Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Large Deformations ◽  
Dielectric Elastomer ◽  
Wave Energy Converter ◽  
Pressure Differential ◽  
Design Stage ◽  
Small Scale ◽  
Energy Converter ◽  
Wide Range ◽  
The Waves

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.

scholarly journals Research of Calibration Method for Industrial Robot Based on Error Model of Position

2021 ◽  
Vol 11 (3) ◽  
pp. 1287
Author(s):  
Tianyan Chen ◽  
Jinsong Lin ◽  
Deyu Wu ◽  
Haibin Wu
Keyword(s):  
Coordinate System ◽  
Industrial Robot ◽  
Calibration Method ◽  
Error Model ◽  
Position Error ◽  
Industrial Robots ◽  
Positioning Error ◽  
Robot Position ◽  
General Measurement ◽  
Parameter Error

Based on the current situation of high precision and comparatively low APA (absolute positioning accuracy) in industrial robots, a calibration method to enhance the APA of industrial robots is proposed. In view of the "hidden" characteristics of the RBCS (robot base coordinate system) and the FCS (flange coordinate system) in the measurement process, a comparatively general measurement and calibration method of the RBCS and the FCS is proposed, and the source of the robot terminal position error is classified into three aspects: positioning error of industrial RBCS, kinematics parameter error of manipulator, and positioning error of industrial robot end FCS. The robot position error model is established, and the relation equation of the robot end position error and the industrial robot model parameter error is deduced. By solving the equation, the parameter error identification and the supplementary results are obtained, and the method of compensating the error by using the robot joint angle is realized. The Leica laser tracker is used to verify the calibration method on ABB IRB120 industrial robot. The experimental results show that the calibration method can effectively enhance the APA of the robot.

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