Performance Criteria to Evaluate a Kinematically Redundant Robotic Cell for Machining Tasks

2012 ◽  
Vol 162 ◽  
pp. 413-422 ◽  
Author(s):  
Kévin Subrin ◽  
Laurent Sabourin ◽  
Grigore Gogu ◽  
Youcef Mezouar
Keyword(s):  
High Speed ◽  
Dynamic Capabilities ◽  
Industrial Robot ◽  
Kinematic Model ◽  
Geometrical Model ◽  
Industrial Robots ◽  
Machining Process ◽  
Performance Criteria ◽  
Robotic Cell ◽  
Speed Accuracy

Machine tools and robots have both evolved fundamentally and we can now question the abilities of new industrial robots concerning accurate task realization under high constraints. Requirements in terms of kinematic and dynamic capabilities in High Speed Machining (HSM) are increasingly demanding. To face the challenge of performance improvement, parallel and hybrid robotic architectures have emerged and a new generation of industrial serial robots with the ability to perform machining tasks has been designed. In this paper, we propose to evaluate the performance criteria of an industrial robot included in a kinematically redundant robotic cell dedicated to a machining task. Firstly, we present the constraints of the machining process (speed, accuracy etc.). We then detail the direct geometrical model and the kinematic model of a robot with closed chain in the arm and we propose a procedure for managing kinematic redundancy whilst integrating various criteria. Finally, we present the evolution of the criteria for a given trajectory in order to define the best location for a rotary table and to analyze the manipulators stiffness.

Study on Improving Accuracy in Robotic Milling of Aluminum Alloy

2018 ◽  
Author(s):  
Shaochun Sui ◽  
Kai Guo ◽  
Jie Sun ◽  
Yiran Zang
Keyword(s):  
Aluminum Alloy ◽  
Industrial Robot ◽  
Vibration Signal ◽  
Industrial Robots ◽  
Machining Process ◽  
Cnc Machine ◽  
Machined Surface ◽  
Improving Accuracy ◽  
High Level ◽  
Monolithic Components

Nowadays, the application of using industrial robots in manufacture is a diminutive due to its own low rigidity and low stiffness. This leads to high level of vibrations that limits the quality and the precision of the workpiece. So they are usually used for welding, grinding and paint shop. However, the potential of industrial robot applications in machining has be realized. The volume of monolithic components is large and there are many issues in machining process such as geometric tolerance and quality of machined surface. In such cases the traditional CNC machine is replaced by industrial robots, which will reduce the production cost, reduce labor and increase the efficiency. In this paper, the milling experiment of 7050-T7451 aeronautical aluminum alloy was carried out by using industrial robot KR210 R2700. In addition, the experiment was employed to study the influence of milling speed, feed-rate, cutting depth and cutting width on vibrations, surface roughness was also measured to evaluate the machining quality. Besides, the axis of angle was changed which led to the different industrial robot’s postures. The vibration signal of different postures was acquired, which was used to analysis the optimal workspace of industrial robot. The best process parameters were obtained, which will play a guiding significance on the actual production.

EFFECT OF SERVO SYSTEMS ON THE CONTOURING ERRORS IN INDUSTRIAL ROBOTS

2012 ◽  
Vol 36 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Mohamed Slamani ◽  
Albert Nubiola ◽  
Ilian A. Bonev
Keyword(s):  
High Speed ◽  
Industrial Robot ◽  
Statistical Tests ◽  
Measurement Instrument ◽  
Servo System ◽  
Industrial Robots ◽  
Structural Vibration ◽  
Tool Centre Point ◽  
Prediction Capability ◽  
Radius Size

Two important aspects of the performance of a servo system, tracking errors and contour errors, significantly affect the accuracy of industrial robots under high-speed motion. Careful tuning of the control parameters in a servo system is essential, if the risk of severe structural vibration and a large contouring error is to be avoided. In this paper, we present an overview of a method to diagnose contouring errors caused by the servo control system of an ABB IRB 1600 industrial robot by measuring the robot’s motion accuracy in a Cartesian circular shape using a double ballbar (DBB) measurement instrument. Tests were carried out at different TCP (tool centre-point) speed and trajectory radii to investigate the main sources of errors that affect circular contouring accuracy. Results show that radius size errors and out-of-roundness are significant. A simple experimental model based on statistical tests was also developed to represent and predict the radius size error. The model was evaluated by comparing its prediction capability in several experiments. An excellent error prediction capability was observed.

Digital Twin: Concept of Hybrid Programming for Industrial Robots — Use Case

2019 ◽  
Author(s):  
Vladimir Kuts ◽  
Martinš Sarkans ◽  
Tauno Otto ◽  
Toivo Tähemaa ◽  
Yevhen Bondarenko
Keyword(s):  
Industrial Robot ◽  
Industrial Robots ◽  
Programming Method ◽  
Shop Floor ◽  
Cell Design ◽  
Robotic Cell ◽  
Digital Twin ◽  
Advantages And Disadvantages ◽  
University Of Technology ◽  
Programming Process

Abstract Modern Industrial Robot (IR) programming process is mainly performed by using three different methods — manual, offline, and online programming. Each of these methods has various advantages and disadvantages. Prominent automotive industries often use a combination of them, as there is no way to avoid one or another form of programming on one factory. However, the use of a combination of different programming methods is time-consuming and demands the operator’s presence on site for reconfiguration of the IR. The primary goal of this study is to introduce and test the concept of a hybrid IR programming method, which combines both: offline and online robotic cell design, programming, and re-configuration methods. Testing of this method is based on fully synchronized robotic cell’s Digital Twin (DT), developed in Industrial Virtual and Augmented Laboratory of Tallinn University of Technology. Usage of the virtual replica allows to plan and program robotic cell on the means of telepresence and interfere with the predefined path of the robot by online programming method. Moreover, this approach reduces the time for robotic cell design and re-programming, enables to minimize downtime of the robotic cell on the factory shop floor. Included Virtual Reality (VR) environment allows simulating a full-scale operator presence on site. Thus, the proposed approach supports an immersive and safe environment for the IR and similar equipment programming purposes.

HIGH-SPEED INDUSTRIAL REAL-TIME NETWORK OF CYBERPHYSICAL SYSTEMS

2019 ◽  
pp. 46-52
Author(s):  
A. A. Zelensky
Keyword(s):  
Real Time ◽  
Cycle Time ◽  
High Speed ◽  
High Efficiency ◽  
Industrial Robot ◽  
Field Tests ◽  
Industrial Robots ◽  
Third Party ◽  
Industrial Equipment ◽  
Industrial Automation

The construction of a high-speed industrial real-time network based on FPGA (Field-Programmable Gate Array) for the control of machines and industrial robots is considered. A brief comparative analysis of the performance of the implemented Ethernet-based Protocol with industrial protocols of other leading manufacturers is made. The aim of the research and development of its own industrial automation Protocol was to reduce the dependence on third-party real-time protocols based on Ethernet for controlling robots, machines and technological equipment. In the course of the study, the requirements for the network of the motion control system of industrial equipment were analyzed. In order to synchronize different network nodes and provide short exchange cycle time, an industrial managed switch was developed, as well as a specialized hardware controller for processing Ethernet packets for end devices, presented as a IP-core. A key feature of the developed industrial network is that the data transmission in it is completely determined, and the exchange cycle time for each of the network devices can be configured individually. High efficiency and performance of implemented network devices became possible due to the use of hardware solutions based on FPGAs. All solutions described in the article as part of a modular digital system have been successfully tested in the control of machines and industrial robot. The results of field tests show that the use of FPGAs and soft processors with specialized peripheral IP-blocks can significantly reduce the tact of managing industrial equipment through the use of hardware computing structures, which indicates the promise of the proposed approach for solving industrial automation tasks.

Control System Design for High Payload Industrial Robot via High Speed Communication Bus and Real-Time System

2011 ◽  
Vol 464 ◽  
pp. 272-278 ◽  
Author(s):  
Wei You ◽  
Min Xiu Kong ◽  
Li Ning Sun ◽  
Chan Chan Guo
Keyword(s):  
Control System ◽  
Real Time ◽  
High Speed ◽  
Industrial Robot ◽  
Engineering Application ◽  
Industrial Robots ◽  
Centralized Control ◽  
Time System ◽  
Real Time System ◽  
High Payload

In this paper, aiming at solving the problems of dynamic coupling effects and flexibility of joints and links, a kind of control system specialized for high payload industrial robots is proposed . After the comparisons between the control systems in all kinds of robots and numerical machines, industrial PC with TwinCAT real-time system is chosen as the motion control unit, EtherCAT is used for command transmitting. The whole control system has a decoupled and centralized control structure. The proposed control system is applied in control of a kind of high payload material handling robots with complex compound control algorithms. The final results shows that the control commands can be easily calculated and transmitted in one sample unit. The proposed control scheme is meaningful to real engineering application.

Study of Neural-Kinematics Architectures for Model-Less Calibration of Industrial Robots

2021 ◽  
Vol 33 (1) ◽  
pp. 158-171
Author(s):  
Monica Tiboni ◽  
◽  
Giovanni Legnani ◽  
Nicola Pellegrini
Keyword(s):  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Kinematic Model ◽  
Back Propagation ◽  
Simulated Data ◽  
Industrial Robots ◽  
Robot Calibration ◽  
Feed Forward Neural Network ◽  
Comparative Performance ◽  
Order Of Magnitude

Modeless industrial robot calibration plays an important role in the increasing employment of robots in industry. This approach allows to develop a procedure able to compensate the pose errors without complex parametric model. The paper presents a study aimed at comparing neural-kinematic (N-K) architectures for a modeless non-parametric robotic calibration. A multilayer perceptron feed-forward neural network, trained in a supervised manner with the back-propagation learning technique, is coupled in different modes with the ideal kinematic model of the robot. A comparative performance analysis of different neural-kinematic architectures was executed on a two degrees of freedom SCARA manipulator, for direct and inverse kinematics. Afterward the optimal schemes have been identified and further tested on a three degrees of freedom full SCARA robot and on a Stewart platform. The analysis on simulated data shows that the accuracy of the robot pose can be improved by an order of magnitude after compensation.

scholarly journals Optimizing Industrial Robots for Accurate High-Speed Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Hubert Gattringer ◽  
Roland Riepl ◽  
Matthias Neubauer
Keyword(s):  
High Speed ◽  
Industrial Robot ◽  
Optimization Techniques ◽  
Industrial Robots ◽  
Industrial Control ◽  
Geometric Calibration ◽  
One Step ◽  
Point Trajectories ◽  
Optimal Efficiency ◽  
Point To Point

Today’s standard robotic systems often do not meet the industry’s demands for accurate high-speed robotic applications. Any machine, be it an existing or a new one, should be pushed to its limits to provide “optimal” efficiency. However, due to the high complexity of modern applications, a one-step overall optimization is not possible. Therefore, this contribution introduces a step-by-step sequence of multiple nonlinear optimizations. Included are optimal configurations for geometric calibration, best-exciting trajectories for parameter identification, model-based control, and time/energy optimal trajectory planning for continuous path and point-to-point trajectories. Each of these optimizations contributes to the improvement of the overall system. Existing optimization techniques are adapted and extended for use with a standard industrial robot scenario and combined with a comprehensive toolkit with discussions on the interplay between the separate components. Most importantly, all procedures are evaluated in practical experiments on a standard robot with industrial control hardware and the recorded measurements are presented, a step often missing in publications in this area.

scholarly journals Industrial robot-based system design of thickness scanning measurement using ultrasonic

2021 ◽  
Vol 12 (1) ◽  
pp. 479-486
Author(s):  
Haibo Liu ◽  
Baoliang Liu ◽  
Meng Lian ◽  
Pingping Li ◽  
Tianran Liu ◽  
...  
Keyword(s):  
High Speed ◽  
Measurement Method ◽  
Industrial Robot ◽  
Thickness Measurement ◽  
Industrial Robots ◽  
Measurement Unit ◽  
Ultrasonic Probe ◽  
State Discrimination ◽  
Thin Walled ◽  
Ultrasonic Thickness

Abstract. Wall thickness is one of the core indicators for measuring the quality of large thin-walled parts such as rocket siding and aircraft skin. However, the traditional handheld thickness measurement method has high labor intensity, low efficiency and poor accuracy consistency. Therefore, an in situ ultrasonic automatic scanning thickness measurement method for large thin-walled parts based on industrial robots is proposed. This “industrial robot + ultrasound” integrated function is a compact system, and a set of innovative methodological or technical solutions is presented, such as (i) TCP and UDP communication protocols being constructed to realize a high-speed and stable communication relationship between the upper computer, robot motion controller and ultrasonic thickness measurement unit; (ii) a coupling gap adjustment method based on eddy-current sensors being adopted to ensure the adaptability of the ultrasonic probe to surface topography of the measured part during scanning measurement; and (iii) a multi-sensor coordinate unified model and coupling gap state discrimination model being established for robot-aided thickness measurement. To verify the feasibility of the proposed method, a series of calibrations and experiments were designed based on the KUKA robot platform and the developed ultrasonic pulse measurement system. Finally, the industrial robot-based ultrasonic thickness scanning measurement has been built and tested for performing the measurement of a rocket tank wall.

scholarly journals A Methodology for Industrial Robot Calibration Based on Measurement Sub-Regions

2021 ◽  
Author(s):  
Juan Sebastian Toquica ◽  
José Maurı́cio Motta
Keyword(s):  
Industrial Robot ◽  
Low Cost ◽  
Kinematic Model ◽  
Measurement Data ◽  
Industrial Applications ◽  
Industrial Robots ◽  
Robot Calibration ◽  
High Precision Measurement ◽  
Measurement Systems ◽  
Robot Accuracy

Abstract This paper proposes a methodology for calibration of industrial robots that uses a concept of measurement sub-regions, allowing low-cost solutions and easy implementation to meet the robot accuracy requirements in industrial applications. The solutions to increasing the accuracy of robots today have high-cost implementation, making calibration throughout the workplace in industry a difficult and unlikely task. Thus, reducing the time spent and the measured workspace volume of the robot end-effector are the main benefits of the implementation of the sub-region concept, ensuring sufficient flexibility in the measurement step of robot calibration procedures. The main contribution of this article is the proposal and discussion of a methodology to calibrate robots using several small measurement sub-regions and gathering the measurement data in a way equivalent to the measurements made in large volume regions, making feasible the use of high-precision measurement systems but limited to small volumes, such as vision-based measurement systems. The robot calibration procedures were simulated according to the literature, such that results from simulation are free from errors due to experimental setups as to isolate the benefits of the measurement proposal methodology. In addition, a method to validate the analytical off-line kinematic model of industrial robots is proposed using the nominal model of the robot supplier incorporated into its controller.

Low Frequency Vibration Consideration in Tool-Path Computation of Two-Link Serial Manipulator for Improved Accuracy

2014 ◽  
Author(s):  
Denis Juschanin ◽  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Mode Coupling ◽  
Tool Path ◽  
Industrial Robot ◽  
Research Question ◽  
Low Frequency ◽  
Industrial Robots ◽  
Machining Process ◽  
Future Research ◽  
Low Frequency Vibration ◽  
Path Computation

Industrial robots are flexible and cost-efficient tools for a multitude of applications such as, polishing, grinding, deburring, and welding. However, their utilization in machining tasks is currently limited due to insufficient position accuracy. This study aims to answer the research question: ‘Does including low frequency vibrations (mode coupling chatter) in tool path computation improve accuracy?’ For this purpose, the current paper focuses on setting-up a robust and flexible simulation framework. The framework implements a predictive cutting force method into a multibody dynamic (MBD) model of an industrial robot. The framework is structured in an extendable fashion for future research tasks. Future work will include mode coupling chatter into the MBD model to help mitigate the effects of chatter in robotic machining process, which in turn will increase tool-path accuracy.

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