Optimal measurement configurations for kinematic calibration of six-DOF serial robot

2011 ◽  
Vol 18 (3) ◽  
pp. 618-626 ◽  
Author(s):  
Tian Li ◽  
Kui Sun ◽  
Zong-wu Xie ◽  
Hong Liu
Keyword(s):  
Kinematic Calibration ◽  
Optimal Measurement ◽  
Serial Robot ◽  
Six Dof

Kinematic calibration of serial robot using dual quaternions

2019 ◽  
Vol 46 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Guozhi Li ◽  
Fuhai Zhang ◽  
Yili Fu ◽  
Shuguo Wang
Keyword(s):  
Kinematic Analysis ◽  
Quaternion Algebra ◽  
Error Model ◽  
Kinematic Calibration ◽  
Dual Quaternion ◽  
Robot Calibration ◽  
Geometrical Meaning ◽  
Content Type ◽  
Dual Quaternions ◽  
Serial Robot

Purpose The purpose of this paper is to propose an error model for serial robot kinematic calibration based on dual quaternions. Design/methodology/approach The dual quaternions are the combination of dual-number theory and quaternion algebra, which means that they can represent spatial transformation. The dual quaternions can represent the screw displacement in a compact and efficient way, so that they are used for the kinematic analysis of serial robot. The error model proposed in this paper is derived from the forward kinematic equations via using dual quaternion algebra. The full pose measurements are considered to apply the error model to the serial robot by using Leica Geosystems Absolute Tracker (AT960) and tracker machine control (T-MAC) probe. Findings Two kinematic-parameter identification algorithms are derived from the proposed error model based on dual quaternions, and they can be used for serial robot calibration. The error model uses Denavit–Hartenberg (DH) notation in the kinematic analysis, so that it gives the intuitive geometrical meaning of the kinematic parameters. The absolute tracker system can measure the position and orientation of the end-effector (EE) simultaneously via using T-MAC. Originality/value The error model formulated by dual quaternion algebra contains all the basic geometrical parameters of serial robot during the kinematic calibration process. The vector of dual quaternion error can be used as an indicator to represent the trend of error change of robot’s EE between the nominal value and the actual value. The accuracy of the EE is improved after nearly 20 measurements in the experiment conduct on robot SDA5F. The simulation and experiment verify the effectiveness of the error model and the calibration algorithms.

Simultaneous identification of joint stiffness, kinematic and hand-eye parameters of measurement system integrated with serial robot and 3D camera

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinlei Zhuang ◽  
Ruifeng Li ◽  
Chuqing Cao ◽  
Yunfeng Gao ◽  
Ke Wang ◽  
...  
Keyword(s):  
Measurement System ◽  
Measurement Accuracy ◽  
Joint Stiffness ◽  
Calibration Method ◽  
Identification Accuracy ◽  
Kinematic Calibration ◽  
Content Type ◽  
3D Camera ◽  
Serial Robot ◽  
Measurement Principle

Purpose This paper aims to propose a measurement principle and a calibration method of measurement system integrated with serial robot and 3D camera to identify its parameters conveniently and achieve high measurement accuracy. Design/methodology/approach A stiffness and kinematic measurement principle of the integrated system is proposed, which considers the influence of robot weight and load weight on measurement accuracy. Then an error model is derived based on the principle that the coordinate of sphere center is invariant, which can simultaneously identify the parameters of joint stiffness, kinematic and hand-eye relationship. Further, considering the errors of the parameters to be calibrated and the measurement error of 3D camera, a method to generate calibration observation data is proposed to validate both calibration accuracy and parameter identification accuracy of calibration method. Findings Comparative simulations and experiments of conventional kinematic calibration method and the stiffness and kinematic calibration method proposed in this paper are conducted. The results of the simulations show that the proposed method is more accurate, and the identified values of angle parameters in modified Denavit and Hartenberg model are closer to their real values. Compared with the conventional calibration method in experiments, the proposed method decreases the maximum and mean errors by 19.9% and 13.4%, respectively. Originality/value A new measurement principle and a novel calibration method are proposed. The proposed method can simultaneously identify joint stiffness, kinematic and hand-eye parameters and obtain not only higher measurement accuracy but also higher parameter identification accuracy, which is suitable for on-site calibration.

A kinematic calibration method based on the product of exponentials formula for serial robot using position measurements

Robotica ◽  
2014 ◽  
Vol 33 (6) ◽  
pp. 1295-1313 ◽  
Author(s):  
Ruibo He ◽  
Xiwen Li ◽  
Tielin Shi ◽  
Bo Wu ◽  
Yingjun Zhao ◽  
...  
Keyword(s):  
Calibration Method ◽  
Kinematic Parameter ◽  
Kinematic Calibration ◽  
Position Measurement ◽  
Error Models ◽  
Position Errors ◽  
Zero Position ◽  
Prismatic Joints ◽  
Serial Robot ◽  
Initial Transformation

SUMMARYBased on product of exponentials (POE) formula, three explicit error models are given in this paper for kinematic calibration of serial robot through measuring its end-effector positions. To obtain these error models, the tool frame should be chosen as reference frame at first, and then each position–error-related segment in the error models using pose measurement should be selected. And during kinematic parameter identification, all the errors in joint twists are identifiable, and the initial transformation errors and the joint zero-position errors can be identified conditionally. Namely, the initial transformation errors are identifiable if they do not contain orientation errors. And the joint zero-position errors are identifiable when a robot only consists of prismatic joints and the coordinates of its joint twists are linearly independent.The effectiveness of this calibration method has been validated by simulations and experiments. The results show that: (1) the identification algorithms are robust and practical. (2) The method of position measurement is superior to that of pose measurement.

Robotic microassembly for meso-scale application

2015 ◽  
Vol 42 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Xin Ye ◽  
Jun Gao ◽  
Zhijing Zhang ◽  
Chao Shao ◽  
Pan Liu
Keyword(s):  
Vision System ◽  
Optical Resolution ◽  
Image Plane ◽  
Objective Lens ◽  
Content Type ◽  
Space Transformation ◽  
Serial Robot ◽  
Six Dof ◽  
Robotic Microassembly ◽  
Meso Scale

Purpose – The purpose of this paper is to design and develop 14-degree of freedom (DOF) robotic micromanipulator with which LIGA devices and axle hole part can be both manipulated and assembled. Design/methodology/approach – The in-house robotic microassembly system is composed of a 6-DOF large motion serial robot with microgrippers, a hexapod six-DOF precision alignment worktable and a vision system whose optical axis of the microscope is parallel with the horizontal plane. A prism with special coating is fixed in front of the objective lens, thus, two-part figures can be acquired simultaneously by the microscope with 1.67 to 9.26 micron optical resolution. The relative discrepancy between the two parts can be calculated from image plane coordinate instead of calculating the space transformation matrix. A modified microgripper was designed to clamp meso-scale parts and its effectiveness was confirmed experimentally. Through the use of the other vision system, the insert action can be successfully manipulated. A laser ranger finder was integrated in this micro-assembly system to measure the assembly result. Findings – A new 14-DOF robotic micromanipulator, including eight axes automatically and six axes manually, has been developed for the assembly of LIGA meso-scale flat parts and axle hole parts. The microassembly system with coaxial alignment function (MSCA) system is able to concurrently manipulate all eight axes automatically and six axes manually. Originality/value – The robotic microassembly is applied in the assembly of meso-scale parts. The new capabilities of the MSCA will allow for the assembly of microsystems more efficiently and more precisely.

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