Novel Kinematic Model of a SCARA-type Robot with Bi-directional Angular Positioning Deviation of Rotary Axes

Zhao Nan

Ibaraki Soichi

The International Journal of Advanced Manufacturing Technology

EISSN 1433-3015

NCID AA11625403

This paper proposed a kinematic model and its calibration scheme to further improve an industrial robot’s absolute positioning accuracy over the entire workspace. To demonstrate the proposed model and its effectiveness in simplified kinematics, this paper only targets a SCARA (Selective Compliance Assembly Robot Arm) -type robot. The proposed model includes not only link length errors and rotary axis angular offsets, widely known as the Denavit-Hartenberg (D-H) parameters, but also the “error map” of the angular positioning deviation of each rotary axis, modelled as a function of command angular position, and the rotation direction to model the influence of backlash. The angular positioning deviation of each rotary axis is identified by measuring the robot’s end-effector position by a laser tracker with indexing each rotary axis at prescribed angular positions. To verify the validity of the identified model, the effectiveness of the compensation based on it is experimentally investigated. By the compensation, the robot’s average absolute position error was reduced by 33% to 0.034mm. Furthermore, this paper experimentally demonstrates that the proposed model can be extended to the radial error motion, axis-to-axis cross talk, and the three-dimensional positioning with orientation errors of axis average lines.

Calibration

Compensation

Kinematic model

Industrial robot

eng

Springer

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature's AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s00170-022-08943-5

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[DOI] https://doi.org/10.1007/s00170-022-08943-5

日本学術振興会

Japan Society for the Promotion of Science

[Crossref Funder] https://doi.org/10.13039/501100001691

「ポータブル」ロボット切削加工システムの基礎となる空間精度の新しい測定法

「ポータブル」ロボット切削加工システムの基礎となる空間精度の新しい測定法

18K03874