Real-time velocity scaling and obstacle avoidance for industrial robots using fuzzy dynamic movement primitives and virtual impedances

2018 ◽  
Vol 45 (1) ◽  
pp. 110-126 ◽  
Author(s):  
Iman Kardan ◽  
Alireza Akbarzadeh ◽  
Ali Mousavi Mohammadi
Keyword(s):  
Real Time ◽  
Obstacle Avoidance ◽  
Time Constant ◽  
Fuzzy System ◽  
Industrial Robots ◽  
Simple Method ◽  
Content Type ◽  
Dynamic Movement ◽  
Steering Mechanism ◽  
Novel Method

Purpose This paper aims to increase the safety of the robots’ operation by developing a novel method for real-time implementation of velocity scaling and obstacle avoidance as the two widely accepted safety increasing concepts. Design/methodology/approach A fuzzy version of dynamic movement primitive (DMP) framework is proposed as a real-time trajectory generator with imbedded velocity scaling capability. Time constant of the DMP system is determined by a fuzzy system which makes decisions based on the distance from obstacle to the robot’s workspace and its velocity projection toward the workspace. Moreover, a combination of the DMP framework with a human-like steering mechanism and a novel configuration of virtual impedances is proposed for real-time obstacle avoidance. Findings The results confirm the effectiveness of the proposed method in real-time implementation of the velocity scaling and obstacle avoidance concepts in different cases of single and multiple stationary obstacles as well as moving obstacles. Practical implications As the provided experiments indicate, the proposed method can effectively increase the real-time safety of the robots’ operations. This is achieved by developing a simple method with low computational loads. Originality/value This paper proposes a novel method for real-time implementation of velocity scaling and obstacle avoidance concepts. This method eliminates the need for modification of original DMP formulation. The velocity scaling concept is implemented by using a fuzzy system to adjust the DMP’s time constant. Furthermore, the novel impedance configuration makes it possible to obtain a non-oscillatory convergence to the desired path, in all degrees of freedom.

Design of Fazl-Tash novel method for sustainable resilient comprehensive supplier selection problem

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamed Fazlollahtabar ◽  
Navid Kazemitash
Keyword(s):  
Supplier Selection ◽  
Huge Number ◽  
Simple Method ◽  
Content Type ◽  
Novel Method ◽  
Rank And Select ◽  
The Cost ◽  
Supplier Selection Problem ◽  
Industrial Company

Purpose However, due to the huge number of studies and on the other hand to be new and creative, the represented models and methods – as the two main parts of this field – have been got more complicated, which consequently have been turned into unpractical research studies for the realistic situations. Therefore, the purpose of this study is the representation of a novel and simple method to deal with the aforementioned gap. Design/methodology/approach To this end, Fazl-Tash method have been proposed, in which a thorough and complete model including 114 criteria and a simple technique to rank and select the best supplier have been presented. Sustainability and resiliency are considered in collecting criteria effective on supplier selection. Findings The method was carried out in a case study in an industrial company. The efficiency of the proposed method is evaluated in comparison with other conventional approaches. Originality/value As selecting the supplier plays a crucial role to bring some important advantages for companies, such as coping with the cost and time problems and influencing the majority of contemporary markets’ requirements, in recent years, there have been representing more effective studies in the supplier selection literature.

scholarly journals The ZKIR Assay, a Real-Time PCR Method for the Detection of Klebsiella pneumoniae and Closely Related Species in Environmental Samples

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Elodie Barbier ◽  
Carla Rodrigues ◽  
Geraldine Depret ◽  
Virginie Passet ◽  
Laurent Gal ◽  
...  
Keyword(s):  
Public Health ◽  
Klebsiella Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Health Concern ◽  
Complex Matrices ◽  
Content Type ◽  
Novel Method ◽  
Pcr Method

ABSTRACT Klebsiella pneumoniae is of growing public health concern due to the emergence of strains that are multidrug resistant, virulent, or both. Taxonomically, the K. pneumoniae complex (“Kp”) includes seven phylogroups, with Kp1 (K. pneumoniae sensu stricto) being medically prominent. Kp can be present in environmental sources such as soils and vegetation, which could act as reservoirs of animal and human infections. However, the current lack of screening methods to detect Kp in complex matrices limits research on Kp ecology. Here, we analyzed 1,001 genome sequences and found that existing molecular detection targets lack specificity for Kp. A novel real-time PCR method, the ZKIR (zur-khe intergenic region) assay, was developed and used to detect Kp in 96 environmental samples. The results were compared to a culture-based method using Simmons citrate agar with 1% inositol medium coupled to matrix-assisted laser desorption ionization–time of flight mass spectrometry identification. Whole-genome sequencing of environmental Kp was performed. The ZKIR assay was positive for the 48 tested Kp reference strains, whereas 88 non-Kp strains were negative. The limit of detection of Kp in spiked soil microcosms was 1.5 × 10−1 CFU g−1 after enrichment for 24 h in lysogeny broth supplemented with ampicillin, and it was 1.5 × 103 to 1.5 × 104 CFU g−1 directly after soil DNA extraction. The ZKIR assay was more sensitive than the culture method. Kp was detected in 43% of environmental samples. Genomic analysis of the isolates revealed a predominance of phylogroups Kp1 (65%) and Kp3 (32%), a high genetic diversity (23 multilocus sequence types), a quasi-absence of antibiotic resistance or virulence genes, and a high frequency (50%) of O-antigen type 3. This study shows that the ZKIR assay is an accurate, specific, and sensitive novel method to detect the presence of Kp in complex matrices and indicates that Kp isolates from environmental samples differ from clinical isolates. IMPORTANCE The Klebsiella pneumoniae species complex Kp includes human and animal pathogens, some of which are emerging as hypervirulent and/or antibiotic-resistant strains. These pathogens are diverse and classified into seven phylogroups, which may differ in their reservoirs and epidemiology. Proper management of this public health hazard requires a better understanding of Kp ecology and routes of transmission to humans. So far, detection of these microorganisms in complex matrices such as food or the environment has been difficult due to a lack of accurate and sensitive methods. Here, we describe a novel method based on real-time PCR which enables detection of all Kp phylogroups with high sensitivity and specificity. We used this method to detect Kp isolates from environmental samples, and we show based on genomic sequencing that they differ in antimicrobial resistance and virulence gene content from human clinical Kp isolates. The ZKIR PCR assay will enable rapid screening of multiple samples for Kp presence and will thereby facilitate tracking the dispersal patterns of these pathogenic strains across environmental, food, animal and human sources.

Fuzzy logic control to improve the performance of the direct power control based DFIG

2013 ◽  
Vol 33 (1/2) ◽  
pp. 254-272 ◽  
Author(s):  
Mohammad Verij Kazemi ◽  
Morteza Moradi ◽  
Reza Verij Kazemi
Keyword(s):  
Fuzzy Logic ◽  
Power Control ◽  
Fuzzy System ◽  
Fuzzy Controller ◽  
New Method ◽  
Direct Power ◽  
Direct Power Control ◽  
Simple Method ◽  
Content Type ◽  
Sector Rotation

Purpose – A direct power control (DPC) of the doubly-fed induction generator (DFIG) is presented. A new method, which is based on the rotation of the space sector, clockwise or vice versa, is proposed to improve the performance of the switching table. Then, it is combined with a fuzzy system to have advantages of both rotation sector and fuzzy controller. The paper aims to discuss these issues. Design/methodology/approach – In this paper, a new DPC of the DFIG is presented. To improve the performance of the switching table, a new method is proposed. The method is based on the rotation of the space sector, clockwise or vice versa. The excellence of the proposed method is proven. Then, it is shown that the performance of the system can be enhanced by using a fuzzy logic controller. The rotation method is combined with a fuzzy system. Findings – Simulation shows that although sector rotation and fuzzy controller can improve the performance of the DFIG, a combination of both demonstrates a smoother response in order that reactive and active power ripples and THD of the injected current decrease in different speeds. Also, it is demonstrated that the proposed method is robust against parameters variations. However, a hardware experiment should be performed to be practically verified. Originality/value – A sector rotation is proposed and its effect on the performance of the DFIG is considered. A simple method to write rules table is presented and the performance of sector rotation and fuzzy controller on the DFIG is analysed.

Acquisition of welding skills in industrial robots

2015 ◽  
Vol 42 (2) ◽  
pp. 156-166 ◽  
Author(s):  
J.F. Aviles-Viñas ◽  
I. Lopez-Juarez ◽  
R. Rios-Cabrera
Keyword(s):  
Real Time ◽  
Learning Process ◽  
Vision System ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Welding Parameters ◽  
Bead Geometry ◽  
Content Type ◽  
Welding Machine ◽  
Vision Algorithm

Purpose – The purpose of this paper was to propose a method based on an Artificial Neural Network and a real-time vision algorithm, to learn welding skills in industrial robotics. Design/methodology/approach – By using an optic camera to measure the bead geometry (width and height), the authors propose a real-time computer vision algorithm to extract training patterns and to enable an industrial robot to acquire and learn autonomously the welding skill. To test the approach, an industrial KUKA robot and a welding gas metal arc welding machine were used in a manufacturing cell. Findings – Several data analyses are described, showing empirically that industrial robots can acquire the skill even if the specific welding parameters are unknown. Research limitations/implications – The approach considers only stringer beads. Weave bead and bead penetration are not considered. Practical implications – With the proposed approach, it is possible to learn specific welding parameters despite of the material, type of robot or welding machine. This is due to the fact that the feedback system produces automatic measurements that are labelled prior to the learning process. Originality/value – The main contribution is that the complex learning process is reduced into an input-process-output system, where the process part is learnt automatically without human supervision, by registering the patterns with an automatically calibrated vision system.

Interfacing an industrial robot and MATLAB for predictive visual servoing

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Megha G. Krishnan ◽  
Abhilash T. Vijayan ◽  
Ashok S.
Keyword(s):  
Real Time ◽  
Control Algorithm ◽  
Visual Servoing ◽  
Industrial Robot ◽  
Effective Communication ◽  
Industrial Robots ◽  
Content Type ◽  
Robot Controller ◽  
Predictive Controller ◽  
And Control

Purpose Real-time implementation of sophisticated algorithms on robotic systems demands a rewarding interface between hardware and software components. Individual robot manufacturers have dedicated controllers and languages. However, robot operation would require either the knowledge of additional software or expensive add-on installations for effective communication between the robot controller and the computation software. This paper aims to present a novel method of interfacing the commercial robot controllers with most widely used simulation platform, e.g. MATLAB in real-time with a demonstration of visual predictive controller. Design/methodology/approach A remote personal computer (PC), running MATLAB, is connected with the IRC5 controller of an ABB robotic arm through the File Transfer Protocol (FTP). FTP server on the IRC5 responds to a request from an FTP client (MATLAB) on a remote computer. MATLAB provides the basic platform for programming and control algorithm development. The controlled output is transferred to the robot controller through Ethernet port as files and, thereby, the proposed scheme ensures connection and control of the robot using the control algorithms developed by the researchers without the additional cost of buying add-on packages or mastering vendor-specific programming languages. Findings New control strategies and contrivances can be developed with numerous conditions and constraints in simulation platforms. When the results are to be implemented in real-time systems, the proposed method helps to establish a simple, fast and cost-effective communication with commercial robot controllers for validating the real-time performance of the developed control algorithm. Practical implications The proposed method is used for real-time implementation of visual servo control with predictive controller, for accurate pick-and-place application with different initial conditions. The same strategy has been proven effective in supervisory control using two cameras and artificial neural network-based visual control of robotic manipulators. Originality/value This paper elaborates a real-time example using visual servoing for researchers working with industrial robots, enabling them to understand and explore the possibilities of robot communication.

Real-time control of bilateral teleoperation system with adaptive computed torque method

2017 ◽  
Vol 44 (3) ◽  
pp. 299-311 ◽  
Author(s):  
Tayfun Abut ◽  
Servet Soyguder
Keyword(s):  
Real Time ◽  
Industrial Robots ◽  
Torque Control ◽  
Position Tracking ◽  
Environment Interaction ◽  
Content Type ◽  
Teleoperation System ◽  
Six Dof ◽  
Visual Interface ◽  
Computed Torque

Purpose This paper aims to use the adaptive computed torque control (ACTC) method to eliminate the kinematic and dynamic uncertainties of master and slave robots and for the control of the system in the presence of forces originating from human and environment interaction. Design/methodology/approach In case of uncertainties in the robot parameters that are utilized in teleoperation studies and when the environment where interactions take place is not known and when there is a time delay, very serious problems take place in system performance. An adaptation rule was created to update uncertain parameters. In addition to this, disturbance observer was designed for slave robot. Lyapunov function was used to analyze the system’s position tracking and stability. A visual interface was designed to ensure that the movements of the master robot provided a visual feedback to the user. Findings In this study, a visual interface was created, and position and velocity control was achieved utilizing teleoperation; the system’s position tracking and stability were analyzed using the Lyapunov method; a simulation was applied in a real-time environment, and the performance results were analyzed. Originality/value This study consisted of both simulation and real-time studies. The teleoperation system, which was created in a laboratory environment, consisted of six-degree-of-freedom (DOF) master robots, six-DOF industrial robots and six-DOF virtual robots.

Real-time monocular 3D perception with ORB-Features

2018 ◽  
Vol 45 (6) ◽  
pp. 776-783
Author(s):  
Babing Ji ◽  
Qixin Cao
Keyword(s):  
Real Time ◽  
3D Structure ◽  
Depth Map ◽  
Depth Estimation ◽  
Industrial Robots ◽  
3D Perception ◽  
Content Type ◽  
Structure Information ◽  
Monocular Camera ◽  
Indoor Scenarios

Purpose This paper aims to propose a new solution for real-time 3D perception with monocular camera. Most of the industrial robots’ solutions use active sensors to acquire 3D structure information, which limit their applications to indoor scenarios. By only using monocular camera, some state of art method provides up-to-scale 3D structure information, but scale information of corresponding objects is uncertain. Design/methodology/approach First, high-accuracy and scale-informed camera pose and sparse 3D map are provided by leveraging ORB-SLAM and marker. Second, for each frame captured by a camera, a specially designed depth estimation pipeline is used to compute corresponding 3D structure called depth map in real-time. Finally, depth map is integrated into volumetric scene model. A feedback module has been designed for users to visualize intermediate scene surface in real-time. Findings The system provides more robust tracking performance and compelling results. The implementation runs near 25 Hz on mainstream laptop based on parallel computation technique. Originality/value A new solution for 3D perception is using monocular camera by leveraging ORB-SLAM systems. Results in our system are visually comparable to active sensor systems such as elastic fusion in small scenes. The system is also both efficient and easy to implement, and algorithms and specific configurations involved are introduced in detail.

Dynamic movement primitives based cloud robotic skill learning for point and non-point obstacle avoidance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhenyu Lu ◽  
Ning Wang
Keyword(s):  
Obstacle Avoidance ◽  
Skill Learning ◽  
Unknown Parameters ◽  
Content Type ◽  
Learning Framework ◽  
Movement Primitives ◽  
Dynamic Movement ◽  
Forcing Function ◽  
Universal Space ◽  
Dynamic Movement Primitives

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.

Robust industrial robot real-time positioning system using VW-camera-space manipulation method

2014 ◽  
Vol 41 (1) ◽  
pp. 70-81 ◽  
Author(s):  
Yong Liu ◽  
Dingbing Shi ◽  
Steven Baard Skaar
Keyword(s):  
Real Time ◽  
Camera Calibration ◽  
Industrial Robot ◽  
Research Problem ◽  
Industrial Applications ◽  
Industrial Robots ◽  
Positioning System ◽  
Content Type ◽  
Time Performance ◽  
The Impact

Purpose – Vision-based positioning without camera calibration, using uncalibrated industrial robots, is a challenging research problem. To address the issue, an uncalibrated industrial robot real-time positioning system has been developed in this paper. The paper aims to discuss these issues. Design/methodology/approach – The software and hardware of this system as well as the methodology are described. Direct and inverse kinematics equations that map joint space into “camera space” are developed. The camera-space manipulation (CSM) algorithm has been employed and improved with varying weights on camera samples of the robot end effector, and the improved CSM is named VW-CSM. The experiments of robot positioning have been conducted using the traditional CSM algorithm and the varying-weight CSM (VW-CSM) algorithm, respectively, both without separate camera calibration. The impact on the accuracy and real-time performance of the system caused by different weights has been examined and discussed. Findings – The experimental results show that the accuracy and real-time performance of the system with the VW-CSM algorithm is better than the one with using the original CSM algorithm, and the impact on the accuracy and real-time performance of the system caused by different weights has been revealed. Originality/value – The accuracy and real-time performance of the system with the VW-CSM algorithm is verified. These results prove that the developed system using the VW-CSM algorithm can satisfy the requirements of most industrial applications and can be widely used in the field of industrial robots.

A novel robot kinematic calibration method based on common perpendicular line model

2018 ◽  
Vol 45 (6) ◽  
pp. 766-775 ◽  
Author(s):  
Chen Shen ◽  
Youping Chen ◽  
Bing Chen ◽  
Yu Qiao
Keyword(s):  
Industrial Robot ◽  
Calibration Method ◽  
Industrial Robots ◽  
Kinematic Calibration ◽  
The Novel ◽  
Perpendicular Line ◽  
Content Type ◽  
Novel Method ◽  
Two Parameters ◽  
Independent Parameters

Purpose This paper aims to propose a novel robot kinematic calibration method based on the common perpendicular line (CPL) model to improve the absolute accuracy of industrial robots. Design/methodology/approach The deviation between the nominal and actual twists is considered the CPL transformation, which includes the rotation about the CPL and the translation along the CPL. By using the invariance of the reciprocal product of the two spatial lines, the previous deviation was analyzed in the neighbor space of the base frame origin. In this space, the line vector of the CPL contained only four independent parameters: two orientation elements and two moment elements. Thus, the CPL model has four independent parameters for the revolute joint and two parameters for the prismatic joint. Findings By simulations and experiment conducted on a SCARA robot and a 6-DOF PUMA robot, the effectiveness of the novel method for calibration of industrial robot is validated. Originality/value The CPL model avoided the normalization and orthogonalization in the iterative identification procedure. Therefore, identifying the CPL model was not only simpler but also more accurate than that of the traditional model. In addition, the results of the CPL transformation strictly conformed to the constraints of the twist.

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