Geometric errors characterization of a five-axis machine tool through hybrid motion of linear-rotary joints

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ORIGINAL ARTICLE

Geometric errors characterization of a five-axis machine tool through hybrid motion of linear-rotary joints Xiaogeng Jiang 1,2 & Hao Wang 1,2 & Sihan Yao 1,2 & Chang Liu 1,2 Received: 18 June 2020 / Accepted: 19 October 2020 / Published online: 11 November 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020

Abstract Position independent geometric errors (PIGEs) of rotary axes, which are caused by imperfections during assembly of machine tools, are proved to be one of the major error sources of a five-axis machine tool. In this paper, PIGEs’ characterization method through hybrid motion of linear-rotary axes using a double ball bar (DBB) is proposed. The coordinated motions involving the motion of a linear and rotary axes are designed, namely, the XC, YC, and ZB motion pairs. The comprehensive error model of the machine tool is established using the screw theory based on the machine tool topology. The asynchronization between the synthetized velocity of the spindle tool cup relative to the workpiece tool cup during the coordinated motions has been resolved based on optimal motion trajectories. The PIGEs are identified using the particle swarm optimization method and simulated using the comprehensive machine tool model. A compensation strategy of the identified errors is proposed using the machine inverse kinematics. The effectiveness of the proposed characterization method is proved by the compensation results. Keywords Position independent geometric errors . Five-axis machine tools . Double ball bar

1 Introduction With the development of modern manufacture, five-axis machine tools have been widely used in aerospace, automobile manufacturing, medical equipment, and many other high added value industries because of their advantages such as better flexibility and higher processing efficiency. Traditional three-axis machine tools are not capable of machining parts with complex shapes such as impellers, blades, and crankshafts, while these parts can be easily processed by five-axis machine tools thanks to the additional rotary axes. But like three-axis machine tools, machining with five-axis machine tools also has error-prone problems due to their complex structure [1]. Researchers have classified machine tool errors according to their sources into geometric errors, thermally induced errors, cutting force-induced errors, and installation errors [1]. Among them, geometric errors are mainly

* Chang Liu [email protected] 1

Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology, Tiangong University, Tianjin 300387, China

2

School of Mechanical Engineering, Tiangong University, Tianjin 300387, China

caused by machine tool assembling errors and component manufacturing defects, forming an important part of the machine tool errors [2]. According to ISO 230-1, geometric errors can be further classified as position dependent geometric errors (PDGEs) and position independent geometric errors (PIGEs) [3]. PDGEs are caused by defects in the machine components, and PIGEs result