A manufacturing-oriented error modelling method for a hybrid machine tool based on the 3-PRS parallel spindle head

Abstract

Five-axis hybrid machine tools are widely used due to the advantages of high speed, high precision, and good performance in the aviation and aerospace manufacturing industry. Many scholars have studied the basic theories and key technologies along with the widespread attention of academia and industry thereon. An integrated geometric error modelling method, under the unified coordinate system framework for a general five-axis hybrid machine tool based on a 3-PRS parallel spindle head, is proposed. The kinematic inverse model of a hybrid machine tool is built using a vector chain method. On the basis of the analysis of the various error sources, an integrated geometric error model is developed based on perturbation theory. Then, the influence of each error source of a hybrid machine tool is investigated at the end-effector. Screw theory is applied to research error source separation for the 3-PRS parallel spindle head of a hybrid machine tool, and a sensitivity analysis of the error sources is undertaken using statistical methods. Based on this, the compensable error sources and non-compensable error sources of a hybrid machine tool are separated successfully. The non-compensable error sources must be strictly controlled in the process of design and manufacture, while the compensable error sources can be compensated inexpensively by software after reaching some degree of accuracy in the design and manufacture. This research provides a theoretical reference for this kind of machine tool design and its use in manufacturing.

Type Synthesis of 2T1R Planar Parallel Mechanisms and Their Moduling Development Applications

“…Among the aforementioned lower-mobility PMs, 3-DOF 2T1R (two translational DOF and one rotational DOF) [15] and 2R1T (two rotational DOF and one translational DOF) [16] PMs especially in the field of constructing 5-DOF hybrid manipulators achieve more and more applications. For example, the parallel part of the five-axis serial-parallel kinematic milling machine SPKM165 [17] is a 3-DOF 2T1R PM, and other well-known five-axis machining centers, such as Ecospeed [18], Tricept [19], Exechon [13], and TriMule [20], are all constructed based on the 3-DOF 2R1T PMs. Up to now, many literatures have studied the valuable 3-DOF 2R1T PMs, but in addition to the 2T1R PM mentioned above, there are few 2T1R PMs available for constructing 5-DOF hybrid manipulators.…”

Minimum-jerk trajectory planning pertaining to a translational 3-degree-of-freedom parallel manipulator through piecewise quintic polynomials interpolation

“…The last three decades have witnessed a considerable development of parallel kinematic manipulators (PKMs) which can be treated as positive encouraging candidates for many advanced automation processes and digitalization applications. [1][2][3][4][5] Undoubtedly, the apparent advantages of PKMs are low moving inertia, high stiffness, high dexterity, and high payload-toweight ratio. These distinct characteristics determine PKMs' increasing widespread utilization in the fields of industrial assembly and practical operations such as high-speed picking and placing, 6 vibration simulator, 7 precise microsurgery, 8 cardiopulmonary resuscitation 9 and so on.…”