A Semiparametric Model-Based Friction Compensation Method for Multi-Joint Industrial Robot

2021 ◽  
Author(s):  
Miao He ◽  
Xiaomin Wu ◽  
Guifang Shao ◽  
Yuhua Wen ◽  
Tundong Liu
Keyword(s):  
Industrial Robot ◽  
Lyapunov Theory ◽  
Industrial Robots ◽  
Learning Ability ◽  
Robot System ◽  
Joint Friction ◽  
Tracking Tasks ◽  
Physical Information ◽  
The Stability ◽  
Six Degree Of Freedom

Abstract Industrial robots have received enormous attention due to their widespread uses in modern manufacturing. However, due to the frictional discontinuous and other unknown dynamics in robotic system, existing researches are limited to simulation and single- or double-joint robot. In this paper, we introduce a semiparametric controller combined by a radial basis function neural network (RBFNN) and complete physical model considering joint friction. First, to extend the NN controller to real-world problems, the continuously differentiable friction (CDF) model is adopted to bring physical information into the learning process. Then, RBFNN is employed to approximate the model error and other unmolded dynamics, and the parameters of CDF model are updated online according to its learning ability. The stability of the robot system can be guaranteed by the Lyapunov theory. The primary parameters of CDF model are determined by the identification experiment and subsequently iteratively updated by the NN. Real-time tracking tasks are performed on a six degree of freedom (DoF) manipulator to follow the desired trajectory. Experimental results demonstrate the effectiveness and superiority of the proposed controller, especially at low speed.

scholarly journals A new joint friction model for parameter identification and sensor-less hand guiding in industrial robots

2020 ◽  
Vol 47 (6) ◽  
pp. 847-857
Author(s):  
Guanghui Liu ◽  
Qiang Li ◽  
Lijin Fang ◽  
Bing Han ◽  
Hualiang Zhang
Keyword(s):  
Industrial Robot ◽  
Angular Displacement ◽  
Weighted Least Squares ◽  
Friction Model ◽  
Industrial Robots ◽  
Model Parameters ◽  
Dynamic Parameters ◽  
Content Type ◽  
Joint Friction ◽  
Six Dof

Purpose The purpose of this paper is to propose a new joint friction model, which can accurately model the real friction, especially in cases with sudden changes in the motion direction. The identification and sensor-less control algorithm are investigated to verify the validity of this model. Design/methodology/approach The proposed friction model is nonlinear and it considers the angular displacement and angular velocity of the joint as a secondary compensation for identification. In the present study, the authors design a pipeline – including a manually designed excitation trajectory, a weighted least squares algorithm for identifying the dynamic parameters and a hand guiding controller for the arm’s direct teaching. Findings Compared with the conventional joint friction model, the proposed method can effectively predict friction factors during the dynamic motion of the arm. Then friction parameters are quantitatively obtained and compared with the proposed friction model and the conventional friction model indirectly. It is found that the average root mean square error of predicted six joints in the proposed method decreases by more than 54%. The arm’s force control with the full torque using the estimated dynamic parameters is qualitatively studied. It is concluded that a light-weight industrial robot can be dragged smoothly by the hand guiding. Practical implications In the present study, a systematic pipeline is proposed for identifying and controlling an industrial arm. The whole procedure has been verified in a commercial six DOF industrial arm. Based on the conducted experiment, it is found that the proposed approach is more accurate in comparison with conventional methods. A hand-guiding demo also illustrates that the proposed approach can provide the industrial arm with the full torque compensation. This essential functionality is widely required in many industrial arms such as kinaesthetic teaching. Originality/value First, a new friction model is proposed. Based on this model, identifying the dynamic parameter is carried out to obtain a set of model parameters of an industrial arm. Finally, a smooth hand guiding control is demonstrated based on the proposed dynamic model.

scholarly journals Dynamic Model Identification for 6-DOF Industrial Robots

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Li Ding ◽  
Hongtao Wu ◽  
Yu Yao ◽  
Yuxuan Yang
Keyword(s):  
Robot Manipulator ◽  
Industrial Robot ◽  
Model Identification ◽  
Friction Model ◽  
Industrial Robots ◽  
Parameters Identification ◽  
Identification Algorithm ◽  
Unknown Parameters ◽  
Joint Friction ◽  
Dynamical Parameters

A complete and systematic procedure for the dynamical parameters identification of industrial robot manipulator is presented. The system model of robot including joint friction model is linear with respect to the dynamical parameters. Identification experiments are carried out for a 6-degree-of-freedom (DOF) ER-16 robot. Relevant data is sampled while the robot is tracking optimal trajectories that excite the system. The artificial bee colony algorithm is introduced to estimate the unknown parameters. And we validate the dynamical model according to torque prediction accuracy. All the results are presented to demonstrate the efficiency of our proposed identification algorithm and the accuracy of the identified robot model.

scholarly journals Analysis of Core Technology Problems and Countermeasures in the Robot Industry

2021 ◽  
Vol 5 (6) ◽  
pp. 19-24
Author(s):  
Xiguang Zhang
Keyword(s):  
Industrial Robot ◽  
Strong Dependence ◽  
Industrial Robots ◽  
Robot System ◽  
High Quality ◽  
Core Technology ◽  
Key Technologies ◽  
Core Components ◽  
Basic Technology ◽  
Technology Level

Since 2013, China has been the world’s largest market for industrial robots. Despite the gradual maturity of the industrial robot system, the lagging R&D and backward technology level of industrial robots have led to a strong dependence on the import of core components and key technologies, which to a certain extent has restricted the development and improvement of industrial robots. At present, the “neck problem” in the field of industrial robots in China is not only in the reducer, controller, and servo but also in the basic processing equipment, basic technology, and basic materials. In this paper, we propose measures to improve the “neck problem” of industrial robots to promote the high-quality development of industrial robots in China.

An Analytical Inverse Kinematics Solution Method for Robotic Manipulators

2000 ◽  
Author(s):  
Tuna Balkan ◽  
M. Kemal Özgören ◽  
M. A. Sahir Arikan ◽  
H. Murat Baykurt
Keyword(s):  
Inverse Kinematics ◽  
Industrial Robot ◽  
Robotic Manipulators ◽  
Inverse Kinematic ◽  
Industrial Robots ◽  
Solution Approach ◽  
Joint Variable ◽  
Forward Kinematic ◽  
Six Degree Of Freedom ◽  
Kinematic Solution

Abstract In this study, an inverse kinematic solution approach applicable to six degree-of-freedom industrial robotic manipulators is introduced. The approach is based on a previously introduced kinematic classification of industrial robotic manipulators by Balkan et al. (1999), and depending on the kinematic structure, either an analytical or a semi-analytical inverse kinematic solution is obtained. The semi-analytical method is named as the parametrized joint variable (PJV) method. Compact forward kinematic equations obtained by utilizing the properties of exponential rotation matrices. In the inverse kinematic solutions of the industrial robots surveyed in the previous study, most of the simplified compact equations can be solved analytically and the remaining few of them can be solved semi-analytically through a numerical solution of a single univariate equation. In these solutions, the singularities and the multiple configurations of the manipulators can be determined easily. By the method employed in this study, the kinematic and inverse kinematic analysis of any manipulator or designed-to-be manipulator can be performed and using the solutions obtained, the inverse kinematics can also be computerized by means of short and fast algorithms. As an example for the demonstration of the applicability of the presented method to manipulators with closed-chains, ABB IRB2000 industrial robot is selected which has a four-bar mechanism for the actuation of the third link, and its compact forward kinematic equations are given as well as the inverse kinematic solution.

Hochpräzises Bearbeiten von Schiffspropellern*/High-precision machining of very large ship propellers

2017 ◽  
Vol 107 (03) ◽  
pp. 182-188
Author(s):  
S. Dryba ◽  
J. Meißner ◽  
M.-C. Prof. Wanner ◽  
O. Wurst
Keyword(s):  
Industrial Robot ◽  
Vital Role ◽  
Industrial Robots ◽  
Precision Machining ◽  
Heavy Duty ◽  
Robot System ◽  
Work Spaces ◽  
Large Ship ◽  
Flexible Applications ◽  
Large Work

In der industriellen Fertigung sind Industrieroboter weit verbreitet [1]. Durch ihre Flexibilität und Schnittstellenvielfalt sind sie für den Ansatz Industrie 4.0 von immenser Bedeutung. Einige Bereiche der Industrie, beispielsweise Gießereien, sind bisher von dieser Entwicklung ausgeschlossen. Viele Werkstücke, die hier zu handhaben oder bearbeiten sind, überschreiten die Arbeitsräume und Lastmomente verfügbarer Industrierobotersysteme. Der Fachbeitrag beschreibt die Entwicklung eines Schwerlast-Großrobotersystems sowie dessen Applikation in einer Gießerei für große Werkstücke.   The use of industrial robots is prevalent in today’s industry [1]. Due to flexible applications and a large variety of interface options, they play a vital role in implementing “Industry 4.0”. As industrial robots offering sufficiently large work spaces and handling heavy payloads are not available today, specific industrial areas, such as foundries, have been mostly excluded from this progress. This paper describes the development of a new heavy-duty industrial robot system, as well as its application in a foundry for large workpieces.

scholarly journals Eyes on the Line

2005 ◽  
Vol 127 (08) ◽  
pp. 25-27
Author(s):  
Gayle Ehrenman
Keyword(s):  
Automotive Industry ◽  
Food Packaging ◽  
Industrial Robot ◽  
Low Cost ◽  
Ease Of Use ◽  
Consumer Electronics ◽  
Industrial Robots ◽  
Production Lines ◽  
Robot System ◽  
Pharmaceutical Production

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.

Positioning Accuracy Reliability of Industrial Robots Through Probability and Evidence Theories

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Dequan Zhang ◽  
Zhouyuan Peng ◽  
Guosong Ning ◽  
Xu Han
Keyword(s):  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Industrial Robots ◽  
Uncertain Parameters ◽  
Analysis Model ◽  
Kinematic Equation ◽  
Positioning Accuracy ◽  
Hybrid Reliability ◽  
The Stability ◽  
Stability And Accuracy

Abstract The positioning accuracy of industrial robots has an important influence on the stability and accuracy of robotic motion, which is one of the important indexes to measure the performance of robots. At present, some probability theory based methods are used to evaluate the positioning accuracy reliability of industrial robots. In practical engineering, the precise probability distribution of some robot’s parameters cannot be obtained directly. This study first uses the aleatory-epistemic hybrid model to describe the uncertain parameters of industrial robots. Second, the uncertain parameters are considered to construct the kinematic equation of industrial robots. Third, a probability-evidence hybrid reliability analysis model of industrial robots is established. Finally, the reliability interval of industrial robots under different thresholds can be obtained. Compared with the traditional method, the reliability results of industrial robots obtained by this method is an interval, which can more objectively evaluate the kinematics reliability of industrial robots. In the example, the effectiveness of the proposed method is verified by a six degrees of freedom (6-DoF) industrial robot.

scholarly journals Research on Trajectory Planning of Six Degrees of Freedom Robot

2019 ◽  
Vol 25 ◽  
pp. 01010
Author(s):  
Hao Zhou
Keyword(s):  
Trajectory Planning ◽  
Degrees Of Freedom ◽  
Simulation Analysis ◽  
Industrial Robot ◽  
Research Direction ◽  
Industrial Robots ◽  
Degree Of Freedom ◽  
Continuous Development ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

With the continuous development of industrial automation, the demand for industrial robots in the manufacturing field is gradually increasing. In order to meet the needs of different occasions and functions, the planning of the trajectory of the robot becomes the research direction of the six-degree-of-freedom robot. The research object of this paper is a six-degree-of-freedom industrial robot. According to engineering needs, a structure of a handling robot is designed. The kinematics of the robot and its trajectory planning are studied, and the simulation analysis is made.

scholarly journals New Approaches to the General Relativistic Poynting-Robertson Effect

2020 ◽  
Vol 4 (3) ◽  
pp. 214-227
Author(s):  
Vittorio De Falco
Keyword(s):  
Three Dimensional ◽  
Analytical Form ◽  
Lyapunov Theory ◽  
Lagrangian Formalism ◽  
Theoretical Approaches ◽  
Effect Model ◽  
Physical Information ◽  
General Relativistic ◽  
The Stability ◽  
First Time

Objectives: A systematic study on the general relativistic Poynting-Robertson effect has been developed so far by introducing different complementary approaches, which can be mainly divided in two kinds: (1) improving the theoretical assessments and model in its simple aspects, and (2) extracting mathematical and physical information from such system with the aim to extend methods or results to other similar physical systems of analogue structure. Methods/Analysis: We use these theoretical approaches: relativity of observer splitting formalism; Lagrangian formalism and Rayleigh potential with a new integration method; Lyapunov theory os stability. Findings: We determined the three-dimensional formulation of the general relativistic Poynting-Robertson effect model. We determine the analytical form of the Rayleigh potential and discuss its implications. We prove that the critical hypersurfaces (regions where there is a balance between gravitational and radiation forces) are stable configurations. Novelty/Improvement: Our new contributions are: to have introduced the three-dimensional description; to have determined the general relativistic Rayleigh potential for the first time in the General Relativity literature; to have provided an alternative, general and more elegant proof of the stability of the critical hypersurfaces.

High Accuracy Analysis of SCARA Industrial Robot Based on Screw Theory

2011 ◽  
Vol 130-134 ◽  
pp. 249-255
Author(s):  
Liang Zhao ◽  
Meng Su ◽  
Yun Chen Miao
Keyword(s):  
Screw Theory ◽  
Industrial Robot ◽  
Dynamic Error ◽  
Error Model ◽  
Industrial Robots ◽  
Inertia Force ◽  
Static System ◽  
Static Error ◽  
Robot System ◽  
Error Sources

Error sources which influence the end-executor’s accuracy are summarized. Based on an analysis of influence caused by the structural error and transmission error, we build a pose error model of industrial robots with screw theory. If regarding the inertia force of the robot system as the external force, the robot system will become a static system. The rigidity can be analyzed using the screw theory, then we establish the dynamic error modle which is caused by the inertia force and gravity. After the error parameters which influence the static error of Selective Compliance Assembly Robot Arm (SCARA) robot are expressed by two-dimensional discrete variable, error space of the end-executor’s track of robot are made. Position error which influenced by the error sources are analysed by comparision of difference. Total accuracy can be improved through controlling the error direction of the static error to counteract the dynamic error's influence. The error model provides an effective theoretical support for the design of industrial robots with different accuracy requirements.

Sign in / Sign up

Export Citation Format

Share Document