scholarly journals Positioning Error Compensation for Industrial Robots Based on Stiffness Modelling

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yingjie Li ◽  
Guanbin Gao ◽  
Fei Liu
Keyword(s):  
Error Compensation ◽  
Compensation Method ◽  
Industrial Robots ◽  
Radial Deformation ◽  
Positioning Error ◽  
Axial Deformation ◽  
Element Analysis ◽  
Positioning Accuracy ◽  
Positioning Errors ◽  
Deformation Error

Insufficient stiffness of industrial robots is a significant factor which affects its positioning accuracy. To improve the positioning accuracy, a novel positioning error compensation method based on the stiffness modelling is proposed in this paper. First, the positioning errors considering the end load and gravity of industrial robots due to stiffness are analyzed. Based on the results of analysis, it is found that the positioning errors can be described by two kinds of deformation errors at joints: the axial deformation error and the radial deformation error. Then, the axial deformation error is modelled by the differential relationship of kinematics equations. The model of radial deformation error is deduced through the recurrence method and rotation transformation between joints. Finally, these two models are transformed into a Cartesian coordinate system, and a positioning error compensation method based on these two models is presented. Simulations based on the finite element analysis are implemented to verify the positioning error compensation method. The results show that the suggested method can efficiently predict the positioning error according to the gravity and loads, so that the positioning accuracy of industrial robots can be improved with the proposed method.

scholarly journals A Non-Delay Error Compensation Method for Dual-Driving Gantry-Type Machine Tool

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 748
Author(s):  
Qi Liu ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Yu Qiao ◽  
Qian Cheng ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Prediction Method ◽  
Compensation Method ◽  
Industrial Robots ◽  
Numerical Control ◽  
Heavy Duty ◽  
Positioning Errors ◽  
Compensation Methods ◽  
Type Machine

The drive at the center of gravity (DCG) principle has been adopted in computer numerical control (CNC) machines and industrial robots that require heavy-duty and quick feeds. Using this principle requires accurate corrections of positioning errors. Conventional error compensation methods may cause vibrations and unstable control performances due to the delay between compensation and motor motion. This paper proposes a new method to reduce the positioning errors of the dual-driving gantry-type machine tool (DDGTMT), namely, a typical DCG-principle-based machine tool. An error prediction method is proposed to characterize errors online. An algorithm is proposed to quickly and accurately compensate the errors of the DDGTMT. Experiment results verify that the non-delay error compensation method proposed in this paper can effectively improve the accuracy of the DDGTMT.

scholarly journals Research on Visualization and Error Compensation of Demolition Robot Attachment Changing

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2428 ◽  
Author(s):  
Qian Deng ◽  
Shuliang Zou ◽  
Hongbin Chen ◽  
Weixiong Duan
Keyword(s):  
Coordinate System ◽  
Coordinate Transformation ◽  
Error Compensation ◽  
Compensation Method ◽  
Positioning Error ◽  
Nuclear Facility ◽  
Reference Coordinate System ◽  
Accuracy Requirement ◽  
Docking Accuracy ◽  
Changing Process

Attachment changing in demolition robots has a high docking accuracy requirement, so it is hard for operators to control this process remotely through the perspective of a camera. To solve this problem, this study investigated positioning error and proposed a method of error compensation to achieve a highly precise attachment changing process. This study established a link parameter model for the demolition robot, measured the error in the attachment changing, introduced a reference coordinate system to solve the coordinate transformation from the dock spot of the robot’s quick-hitch equipment to the dock spot of the attachment, and realized error compensation. Through calculation and experimentation, it was shown that the error compensation method proposed in this study reduced the level of error in attachment changing from the centimeter to millimeter scale, thereby meeting the accuracy requirements for attachment changing. This method can be applied to the remote-controlled attachment changing process of demolition robots, which provides the basis for the subsequent automatic changing of attachments. This has the potential to be applied in nuclear facility decommissioning and dismantling, as well as other radioactive environments.

scholarly journals A Positioning Error Compensation Method for a Mobile Measurement System Based on Plane Control

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 294
Author(s):  
Bo Shi ◽  
Fan Zhang ◽  
Fanlin Yang ◽  
Yanquan Lyu ◽  
Shun Zhang ◽  
...  
Keyword(s):  
Measurement System ◽  
Error Compensation ◽  
Point Cloud ◽  
Satellite System ◽  
Compensation Method ◽  
Positioning Error ◽  
Signal Loss ◽  
Middle Point ◽  
Existing Building ◽  
Mobile Measurement

Global navigation satellite system (GNSS)/inertial navigation system (INS) navigation technology is one of the core technologies in a mobile measurement system and can provide real-time geo-referenced information. However, in the environment measurements, buildings cover up the GNSS signal, causing satellite signals to experience loss-of-lock. At this time errors of INS independent navigation accumulate rapidly, so it cannot meet the needs of the mobile measurement system. In this paper, a positioning error compensation method based on plane control is proposed by analyzing the error characteristics of position and orientation caused by satellite signal loss-of-lock in the urban environment. This method control uses planar features and the laser point cloud positioning equation to establish an adjustment model that ignores the influence of the attitude error and finds the positioning error at the middle point of the GNSS signal loss-of-lock time period, and then compensates for the error at other points by using the characteristics of the positioning error. The experimental results show that the accuracy of the compensated laser point cloud has been significantly improved, and the feasibility of the method is verified. Meanwhile, the method can rely on the existing building plane so the method is adaptable and easy to implement.

Positioning Error Compensation for Machining Center Based on Spline Interpolation

2012 ◽  
Vol 472-475 ◽  
pp. 3029-3034
Author(s):  
Peng Li ◽  
Ying Hu ◽  
Zi Ma
Keyword(s):  
Error Compensation ◽  
Laser Interferometer ◽  
Spline Interpolation ◽  
Machining Process ◽  
Accuracy Evaluation ◽  
Positioning Error ◽  
Positioning Errors ◽  
Machining Center ◽  
Compensation Function ◽  
Manual Correction

Related to the machining precision, especially for the middle and low end machining center, the positioning error is often considered as a major factor, which can be traditionally decreased by the pitch compensation function integrated in the CNC system. However, the function is just founded on that all of positioning errors remain constant in the machining process, and it is difficulty to meet the compensation needs in different machining condition. At the same time, it involves a mass of parameters that need professional manual correction. Therefore, the software error compensation method is put forward. Firstly, based on cubic spline interpolation, the error compensation model is designed through the processing of positioning error which is collected by the laser interferometer. Secondly, with the characteristics of G codes, the database is established for error compensation, which can effectively correct different machining G codes with enough error information. Finally, by the experiment and accuracy evaluation, results show that after the positioning error of machining center is compensated by the presented scheme, its precision is improved obviously.

The Parameter Identification and Error Compensation of Robot Based on Dynacal System

2014 ◽  
Vol 701-702 ◽  
pp. 788-792 ◽  
Author(s):  
Fei Qi ◽  
Xue Liang Ping ◽  
Jie Liu ◽  
Yi Jiang
Keyword(s):  
Parameter Identification ◽  
Error Compensation ◽  
Compensation Method ◽  
Positioning Accuracy ◽  
Mean Error ◽  
Robot Positioning ◽  
The Mean

According to the robot positioning accuracy, this paper proposed an error compensation method after updating the controller parameters based on the D-H parameters model and Dynacal system. The proposed method is effectiveand was validated on the developed robot of which the mean error was reduced to 0.092mm. The method can greatly improve the positioning accuracy of the robot.

scholarly journals Compensation for absolute positioning error of industrial robot considering the optimized measurement space

2020 ◽  
Vol 17 (2) ◽  
pp. 172988142092164
Author(s):  
Junde Qi ◽  
Bing Chen ◽  
Dinghua Zhang
Keyword(s):  
Industrial Robot ◽  
Measurement Data ◽  
Joint Space ◽  
Industrial Robots ◽  
Positioning Error ◽  
Positioning Accuracy ◽  
Decoupling Method ◽  
Absolute Positioning ◽  
Motion Characteristics ◽  
High Flexibility

Industrial robots are getting widely applied due to their low use-cost and high flexibility. However, the low absolute positioning accuracy limits their expansion in the area of high-precision manufacturing. Aiming to improve the positioning accuracy, a compensation method for the positioning error is put forward in terms of the optimization of the experimental measurement space and accurate modelling of the positioning error. Firstly, the influence of robot kinematic performance on the measurement accuracy is analysed, and a quantitative index describing the performance is adopted. On this basis and combined with the joints motion characteristics, the optimized measurement space in joint space as well as Cartesian space is obtained respectively, which can provide accurate measurement data to the error model. Then the overall model of the positioning error is constructed based on modified Denavit–Hartenberg method, in which the geometric errors and compliance errors are considered comprehensively, and an error decoupling method between them is carried out based on the error-feature analyses. Experiments on the KUKA KR210 robot are carried out finally. The mean absolute positioning accuracy of the robot increases from 1.179 mm to 0.093 mm, which verifies the effectiveness of the compensation methodology in this article.

A calibration method for enhancing robot accuracy through integration of kinematic model and spatial interpolation algorithm

2021 ◽  
pp. 1-27
Author(s):  
Junde Qi ◽  
Bing Chen ◽  
Dinghua Zhang
Keyword(s):  
Spatial Interpolation ◽  
Residual Error ◽  
Compensation Method ◽  
Industrial Robots ◽  
Interpolation Algorithm ◽  
Random Errors ◽  
Spatial Error ◽  
Positioning Accuracy ◽  
Absolute Positioning ◽  
The Impact

Abstract Industrial robots are finding their niche in the field of machining due to their advantages of high flexibility, good versatility and low cost. However, limited by the low absolute positioning accuracy, there are still huge obstacles in high precision machining processes such as grinding. Aiming at this problem, a compensation method combining analytical modeling for quantitative errors with spatial interpolation algorithm for random errors is proposed based on the full consideration of the source and characteristics of positioning errors. Firstly, as for the quantitative errors, namely geometric parameter and compliance error in this paper, a kinematics-based error model is constructed taking the coupling effect of errors into consideration. Then avoiding the impact of random errors, the extended Kalman filtering algorithm (EKF) is adopted to identify the error parameters. Secondly, based on the similarity principle of spatial error, spatial interpolation algorithm is used to model the residual error caused by temperature, gear clearance etc. Based on the spatial anisotropy characteristics of robot motion performance, an adaptive mesh division algorithm was proposed to balance the accuracy and efficiency of mesh division. Then, an inverse distance weighted interpolation algorithm considering the influence degree of different joints on the end position was established to improve the approximation accuracy of residual error. Finally, the rough-fine two-stage serial error compensation method was carried out. Experimental results show the mean absolute positioning accuracy is improved from 1.165 mm to 0.106 mm, which demonstrates the effectiveness of the method in this paper.

An Immediate Error Compensation Method for PCB Alignment Based on Image Measurement

2014 ◽  
Vol 602-605 ◽  
pp. 1693-1697
Author(s):  
Qi Zhang ◽  
Hong Lin Ma ◽  
Yong Ting Zhao ◽  
Jie Yang ◽  
Bin Zheng
Keyword(s):  
Error Compensation ◽  
Compensation Method ◽  
Alignment Method ◽  
Image Measurement ◽  
Motion Direction ◽  
Positioning Accuracy ◽  
Experimental Prototype ◽  
Initial Design

The parallelism between an industrial camera and a servo motion direction is corrected with the help of image measurement to shadowed geometric contours. Then a nearly orthogonal angle between XY servo motion directions is obtained according to an inherent geometry relationship in contours. The installation error of a PCB in platform is compensated based on automatic multi-spot imaging finally. An experimental prototype was built while the PCB alignment was implemented on a lot of samples according to the method introduced above. It proves that the developed immediate alignment method as well as its specific embodiment fulfills the requirement of positioning accuracy in the initial design.

Sign in / Sign up

Export Citation Format

Share Document