Machine Tool Axis Dynamics

Whalley, R.; Ebrahimi, Morteza; Abdul-Ameer, A.

doi:10.1243/09544062c15904

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…Therefore, studying the detailed structure of the servo feed system and using computer simulation methods to estimate its behavior under the specified input are of great significance to research the dynamic processing performance for the five-axis machine tools. 22–24 Some researchers 25,26 have tried to use the model identification method 27,28 to obtain the transfer function of the servo feed system for a specific machine tool. At present, the machine tool control system on the market is no longer a simple proportional–integral–derivative (PID) control, 29,30 and its specific control methods are difficult to acquire.…”

Section: Introductionmentioning

confidence: 99%

A novel method for evaluating the validity of dynamic accuracy test pieces for five-axis machine tools

Wang

Guan

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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The detection method for direct machining the standard test pieces, which is commonly employed to exhibit the machining precision of five-axis machine tools, can truly reflect the dynamic accuracy of five-axis machine tools in the actual machining process. Existing theories on explaining the phenomenon that the ability of S-shaped test pieces to detect dynamic accuracy for five-axis machine tools are stronger than those of NAS979 test pieces mostly used the qualitative research methods, and they cannot be quantitatively used to reveal the mathematical relationship between machine tools and test pieces. Therefore, this article makes the first attempt to investigate the quantitative evaluation method for the validity of dynamic accuracy test pieces. The dynamic error function of the servo feed system in the frequency domain was derived first by establishing the mechanical system model and control system model. The method of dipole cancellation was used to acquire a simplified transfer function for the dynamic error affected by the input. Based on the zero-order hold property of the discrete input signals, the expression of dynamic error affected by input in the time domain, which intuitively shows the mathematical relationship among the machine tool performances, the test piece characteristics and the dynamic error of the servo feed system, was obtained. Then, the novel evaluation methods of the linear combinatorial value and the combinatorial linear combinatorial value were proposed. A series of comparative analyses between an S-shaped test piece and an NAS979 test piece were carried out based on the proposed new evaluation methods. A machining experiment conducted on a five-axis machine tool is used to verify the evaluation results.

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Section: Introductionmentioning

confidence: 99%

A novel method for evaluating the validity of dynamic accuracy test pieces for five-axis machine tools

Wang

Guan

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Research efforts have been primarily concentrated on dynamic modeling of the screw, nut, bearings, motor and guide [5]. Many researchers focusing on the improvement of more accurate modeling [6][7][8][9]. The discrepancy between the simulation and measurements are still existed, even the virtual design and analysis model of the ball-screw drive is useful during prototyping of the machine tool and controller [10].…”

Section: Introductionmentioning

confidence: 99%

Rapid prototyping and numerical identification of feed drive system using hardware-in-loop realization

Chen

2020

Eng. Res. Express

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Nowadays, the virtual manufacturing is proved to be the promising technology to design a completely digital feed drive system. Especially, the initial parameters tuning, tests, error prediction and diagnostics at the actual location of the feed drive system are at a risk of stressing and even damaging the machine tool. This paper presents an analytical identification method of feed drive system based on HILS (Hardware-In-Loop System), allowing a real CNC to be prototyped quickly from standard library functions for feed drive control laws. The main purpose of drive identification outside the CNC is that it may not be performed when the drive is installed in the CNC and user has no access to the internal control structure. So, it is proposed to identify it outside CNC in the proposed HILS on the basis of a comparison of the real object and its nominal dynamic model. The rapid prototyping model can be easily executed for initial parameters tuning, testing and the risk of stressing and damaging the machine tool during the diagnosis can be avoided effectively as well. The methodology is quite general and applicable to linear or ball screw drives, controlled with commonly used controllers. Furthermore, additional CNC modules can easily be prototyped and integrated to this prototype for other research purposes. Experiments were carried out to compare HILS prototyping to the actual CNC systems. The result demonstrates that the real-time feed drive system can be accurately represented by the identified prototype model.

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“…10 and Khalil and Gautier 11 built a dynamic model of the ball-screw feed system in the feed direction. Considering the flexibility of the screw-shaft and kinematic joints, 12–14 a beam element dynamic model of a ball-screw feed system for machine tool was established to analyze its dynamic characteristics. For a ball-screw feed system, a hybrid dynamic model was established by Zhou et al., 15 and the dynamic characteristics variation of the screw-shaft itself with different axial stiffness of the bearing joints was analyzed.…”

Section: Introductionmentioning

confidence: 99%

Dynamics analysis of a slender ball-screw feed system considering the changes of the worktable position

Zhang

Liu

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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For a slender ball-screw feed system, the position of the screw–nut joints will change greatly when the moving worktable moves along its whole stroke. Therefore, the compression/tension and torsion stiffness of the screw-shaft on both sides of the screw–nut joints will change. Thus, the system transmission stiffness will also vary and affect its dynamics. In this article, considering the changes of the worktable position and using hybrid element method, a dynamic model was established for the slender ball-screw feed system, and a calculation method of the system stiffness and mass matrix was provided. The experiments on the slender ball-screw feed system with different positions were also performed to verify the proposed dynamic model. Finally, the influences of length, screw-tension force, pitch, nominal diameter of screw and rated dynamic load of screw-nut joints on the slender ball-screw feed system’s natural frequency along its whole stroke were studied. The results showed that the slender ball-screw feed system possesses obvious position-dependent variable dynamics along its whole stroke; the ratio of length to diameter of the screw ( Lf/ d0) would be better designed smaller than 50 in order to obtain the relative uniformity of the system dynamics when manufacturing large machine tools.

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Machine Tool Axis Dynamics

Cited by 17 publications

References 16 publications

A novel method for evaluating the validity of dynamic accuracy test pieces for five-axis machine tools

A novel method for evaluating the validity of dynamic accuracy test pieces for five-axis machine tools

Rapid prototyping and numerical identification of feed drive system using hardware-in-loop realization

Dynamics analysis of a slender ball-screw feed system considering the changes of the worktable position

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