Load Estimation and Compensation Control of a Vertical Two-Link Robot

1990 ◽  
Vol 2 (2) ◽  
pp. 107-113
Author(s):  
Yoshitake Kobayashi ◽  
◽  
Kazuo Yamafuji ◽  

It is widely recognized that the industrial robots used in production lines or in other engineering fields are installed with comparatively higher rated actuators and have higher rigidity than required, whereas they have too small payload capacity. To achieve high speed drive and accurate positioning under a high payload is indispensable for an advanced industrial robot. In order to increase payload/deadweight ratio without losing high speed driving and accurate control of robots, the nonlinear terms in the equations of motion relating to their load and attitude must be well compensated. The authors have developed and examined two kinds of load estimation and compensation control methods for a vertical-type manipulating robot, which are based on gravity estimation-compensation and fuzzy-set theory. It is confirmed experimentally that although both compensating methods are useful, the fuzzy theory is much better than the gravity compensation method.

2011 ◽  
Vol 464 ◽  
pp. 272-278 ◽  
Author(s):  
Wei You ◽  
Min Xiu Kong ◽  
Li Ning Sun ◽  
Chan Chan Guo

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.


Author(s):  
Mohamed Slamani ◽  
Albert Nubiola ◽  
Ilian A. Bonev

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.


Author(s):  
A. A. Zelensky

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Hubert Gattringer ◽  
Roland Riepl ◽  
Matthias Neubauer

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.


2021 ◽  
Vol 12 (1) ◽  
pp. 479-486
Author(s):  
Haibo Liu ◽  
Baoliang Liu ◽  
Meng Lian ◽  
Pingping Li ◽  
Tianran Liu ◽  
...  

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.


2005 ◽  
Vol 127 (08) ◽  
pp. 25-27
Author(s):  
Gayle Ehrenman

This article discusses vision-enabled robots that are helping factories to keep the production lines rolling, even when the parts are out of place. The automotive industry was one of the earliest to adopt industrial robots, and continues to be one of its biggest users, but now industrial robots are turning up in more unusual factory settings, including pharmaceutical production and packaging, consumer electronics assembly, machine tooling, and food packaging. No current market research is available that breaks down vision-enabled versus blind robot usage. However, all the major industrial robot manufacturers are turning out models that are vision-enabled; one manufacturer said that its entire current line of robots are vision enabled. All it takes to change over the robot system is some fairly basic tooling changes to the robot's end-effector, and some programming changes in the software. The combination of speed, relatively low cost , flexibility, and ease of use that vision-enabled robots offer is making an increasing number of factories consider putting another set of eyes on their lines.


2012 ◽  
Vol 162 ◽  
pp. 413-422 ◽  
Author(s):  
Kévin Subrin ◽  
Laurent Sabourin ◽  
Grigore Gogu ◽  
Youcef Mezouar

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.


2019 ◽  
Vol 8 (3) ◽  
pp. 6280-6284

Teleoperation is an operation needed to complete a variety of robot tasks in dangerous and difficult-to-reach environments. In the industrial world, teleoperation robots can be used to help humans complete dangerous tasks such as grasping and lifting in the nuclear industry. Controlling industrial robots can be done remotely via the Internet. However, communication still needs to be improved so that it can achieve low latency, be safe, high reliability, and be interoperable. This study proposes the use of the XMPP protocol to handle data interactions between robots and cloud platform. We modified the Robot Operating System (ROS) package by adding a special node that bridges communication using the XMPP protocol. We compare the performance of MQTT with the HTTP protocol. The test results show that the MQTT latency time is better than HTTP. The results of this study can be used in robot teleoperation operations in various industries that consider aspects of communication quality


2021 ◽  
Vol 49 (1) ◽  
pp. 44-55
Author(s):  
Mikhail Polishchuk ◽  
M. Tkach

At present, robotization of assembly processes is achieved through the use of industrial robots with high positioning accuracy in conjunction with tactile means of adaptation to the conditions of assembly of precision parts. The cost of such robots is many times higher than the cost of simple robots with low positioning accuracy of the robot arm. The research in this article is aimed at reducing the cost of assembly processes for precision parts by applying the position correction of the connected parts not by the robot hand, but by an additional technological module that is installed on the manipulator of a simple robot and performs high-speed stochastic mismatch scan of assembly objects. The article presents the results of a full factorial experiment of the process of joining precision cylindrical parts with a gap of no more than 3...5 microns. A regression model of this process is proposed, a formula for calculating the quasi-optimal modes of precision assembly and graphanalytical dependences of the assembly time on the scanning modes of the misalignment of assembly objects are given. The proposed high-speed method for compensating for the positioning error of an industrial robot makes it possible to assemble precision parts in a very short time within 1...3(s). The main economic effect of the research results is that the device for scanning the misalignment of assembly objects, which is installed on the arm of an inexpensive robot with a low positioning accuracy, can significantly increase the assembly speed and reduce capital investments in robotic assembly of high-precision parts.


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