Gyroscopic Torque Analysis and Dynamic Balance Test of the Vertical Aerostatic Spindle

2011 ◽  
Vol 697-698 ◽  
pp. 686-691
Author(s):  
Fei Hu Zhang ◽  
Peng Qiang Fu ◽  
C.H. An ◽  
Jiu Wei Sun ◽  
Sheng Fei Wang
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Pressure ◽  
Dynamic Balance ◽  
Reaction Force ◽  
Rigid Body Dynamics ◽  
Machining Accuracy ◽  
Balance Test ◽  
Close Relationship ◽  
Ultra Precision ◽  
Aerostatic Spindle

Ultra-precision flying cutting machining with a vertical milling style is an important means of ultra-precision machining. It has a close relationship between the machining accuracy and the dynamic characteristics of the aerostatic spindle. The film force acting on the spindle rotor is related to the manufacture, installation and static unbalance or dynamic imbalance or other factors. Therefore, it is necessary to analyze the dynamic pressure force caused by these factors in order to study on the rotor posture and quantitative movement of the spindle. This article derived the solution formula for the dynamic pressure reaction force of the ultra-precision machine tool spindle with vertical static film based on the basic theory of the rigid body dynamics. The gyroscopic torque of the spindle has been analyzed under different conditions with the spindle dynamic balancing tests, which provide a reference to the further analysis of the spindle dynamic characteristics.

scholarly journals A prediction model of the surface topography due to the unbalance of the spindle system in ultra-precision fly-cutting machining

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774714
Author(s):  
Dongju Chen ◽  
Xianxian Cui ◽  
Ri Pan ◽  
Jinwei Fan ◽  
Chenhui An
Keyword(s):  
Prediction Model ◽  
Surface Topography ◽  
Rotation Speed ◽  
Surface Generation ◽  
Machining Accuracy ◽  
Machined Surface ◽  
Spindle System ◽  
Fly Cutting ◽  
Ultra Precision ◽  
Aerostatic Spindle

In ultra-precision fly-cutting machining, the aerostatic spindle is the key component, which has significant influence on the machined surface quality. The unbalanced spindle directly affects the machining accuracy. In this article, a prediction model of machining surface topography is proposed which involves the effect of the gas film performance of spindle in microscale. With the Weierstrass function, unstable transient response of the aerostatic spindle system is derived by the motion model of the spindle, which response signal represents the surface profile in the ultra-precision machining. Meanwhile, the experiment is performed with different rotation speed of the spindle. And the effect of the unbalanced aerostatic spindle on the surface generation is discussed in time and frequency domain. The conclusion shows that the similar cyclical surface ripple of the workpiece is independent of the spindle speed, and the rotation speed of the spindle and unbalanced spindle directly affects the machining surface topography. This study is quite meaningful for deeply understanding the influence rule of spindle unbalanced error from the viewpoint of machined surface and vibration frequency.

Measurement and analysis for frequency domain error of ultra-precision spindle in a flycutting machine tool

2016 ◽  
Vol 232 (9) ◽  
pp. 1501-1507 ◽  
Author(s):  
Guoda Chen ◽  
Yazhou Sun ◽  
Chenhui An ◽  
Feihu Zhang ◽  
Zhiji Sun ◽  
...  
Keyword(s):  
Machine Tool ◽  
Frequency Domain ◽  
Frequency Domain Analysis ◽  
Frequency Characteristics ◽  
Machining Process ◽  
Machining Accuracy ◽  
Machined Surface ◽  
Ultra Precision ◽  
Machining Process Planning ◽  
Aerostatic Spindle

The ultra-precision spindle is the key component of ultra-precision machine tool, which largely influences the machining accuracy. Its frequency characteristics mainly affect the frequency domain error of the machined surface. In this article, the error measurement setup for the ultra-precision aerostatic spindle in a flycutting machine tool is established. The dynamic and multi-direction errors of the spindle are real-time measured under different rotation speeds. Then, frequency domain analysis is carried out to obtain its regularity characteristics based on the measurement result. Through the analysis, the main synchronous and asynchronous errors with relatively large amplitude of the spindle errors are found, and the amplitude change law of these main spindle errors is obtained. Besides, the cause of the main synchronous and asynchronous errors is also analyzed and indicated. This study deepens the understanding of ultra-precision spindle dynamic characteristics and plays the important role in the spindle frequency domain errors’ control, machining process planning, frequency characteristics analysis and oriented control of the machined surface errors.

scholarly journals Effects of a 6-week core stabilization training program on dynamic balance and trunk stabilization endurance of horse riders

2021 ◽  
Author(s):  
Nicholas H. K. Lam ◽  
Wai Man Lau ◽  
Tin Lap Lau
Keyword(s):  
Training Program ◽  
Dynamic Balance ◽  
Measurement Tool ◽  
Balance Test ◽  
Core Stabilization ◽  
Balance Task ◽  
Postural Stabilization ◽  
Left And Right ◽  
Back Extensor ◽  
Swiss Ball

AbstractThe purpose of this study was to examine the effectiveness of a 6-week core stabilization training program (CSTP) in improving dynamic balance and back-extensor endurance of horse riders; and develop a measurement tool in assessing the dynamic postural stabilization endurance for horse riders. Twelve male horse riders (age: 23.58 ± 1.93 years; height: 165.09 ± 4.60 cm; weight: 56.53 ± 4.75 kg; experience in horse racing: 1.75 ± 0.34 years) completed 12 training sessions in 6 weeks. Subjects performed the CSTP with two progressions. CSTP started with the basic consciousness activation exercises, and then eliminated visual feedback in dynamic balance task on unstable surfaces and finished with switching the center of gravity. Moderate-to-large difference was demonstrated in the Y-Balance test scores for right leg (102.81 ± 8.32 vs 106.471 ± 4.35 cm, d = 0.55, 95% CL 0.00 to 1.08) and left leg (102.04 ± 3.20 vs 106.29 ± 3.62 cm, d = 1.25, 95% CL 0.41 to 2.05) following 6 weeks CSTP. However, trivial to small differences was reported between left and right leg in pre (d = 0.12, 95% CL − 0.49 to 0.73) and post 6-week CSTP (d = 0.04, 95% CL − 0.69 to 0.78). Biering–Sørensen test (BST) shows largely greater performance after 6-week CSTP (98.3 ± 30.1 vs 131.8 ± 19.0 s, d = 1.33, 95% CL 0.54–2.09). A novel measurement, Swiss ball four-point kneeling test was shown to be correlated with the change in BST (r = 0.633).

scholarly journals The Relationship between Dynamic Balance and Jumping Tests among Adolescent Amateur Rugby Players. A Preliminary Study

2021 ◽  
Vol 18 (1) ◽  
pp. 312
Author(s):  
Bartosz Wilczyński ◽  
Jakub Hinca ◽  
Daniel Ślęzak ◽  
Katarzyna Zorena
Keyword(s):  
Injury Risk ◽  
Dynamic Balance ◽  
Study Data ◽  
Balance Test ◽  
Risk Of Injury ◽  
Counter Movement Jump ◽  
Increased Risk ◽  
Positive Correlations ◽  
The Relationship ◽  
Rugby Players

Rugby is a demanding contact sport. In light of research, poor balance, reduced jumping ability, muscle strength, and incorrect landing patterns might contribute to the increased risk of injury in athletes. Investigating the relationship between tests assessing these abilities might not only allow for the skillful programming of preventive training but also helps in assessing the risk of injury to athletes. Thus, the main purpose of this study was to investigate the relationship between dynamic balance, vertical and horizontal jumps, and jump-landings movement patterns. Thirty-one healthy amateur adolescent rugby players (age: 14.3 ± 1.6 years, height 171.4 ± 9.7 cm, body mass 80 ± 26 kg) participated in the study. Data were collected by the Y-balance Test (YBT), Counter Movement Jump (CMJ), Single Leg Hop for Distance (SLHD), and Landing Error Score System (LESS). Significant positive correlations were found between SLHD both legs (SLHDb) and YBT Composite both legs (COMb) (r = 0.51, p = 0.0037) and between SLHDb and CMJ (r = 0.72, p < 0.0001). A relationship was also observed between the CMJ and YBT COMb test (r = 0.51, p = 0.006). Moderate positive correlations were found between the dominant legs in SLHD and the posterolateral (r = 0.40, p = 0.027), posteromedial (r = 0.43, p = 0.014), and composite (r = 0.48, p = 0.006) directions of the YBT. These results indicate that variables that are dependent on each other can support in the assessment of injury-risk and in enhancing sports performance of young athletes.

Comparison of Two Rehabilitation Protocols on Patient- and Disease-Oriented Outcomes in Individuals With Chronic Ankle Instability

2017 ◽  
Vol 22 (3) ◽  
pp. 57-65 ◽  
Author(s):  
Kyle Kosik ◽  
Masafumi Treada ◽  
Ryan McCann ◽  
Samantha Boland ◽  
Phillip A. Gribble
Keyword(s):  
Ankle Instability ◽  
Dynamic Balance ◽  
Controlled Trial ◽  
Intervention Programs ◽  
Foot And Ankle ◽  
Balance Test ◽  
Randomized Controlled ◽  
Rehabilitation Protocols ◽  
Main Effect ◽  
Ability Measure

Proximal neuromuscular alterations are hypothesized to contribute to the patient- and disease-oriented deficits observed in CAI individuals. The objective was to compare the efficacy of two 4-week intervention programs with or without proximal joint exercises. Twenty-three individuals with CAI completed this single-blinded randomized controlled trial. Outcome measures included the Star Excursion Balance Test (SEBT) and the Foot and Ankle Ability Measure (FAAM). A time main effect was observed for the FAAM-ADL (p = .013), FAAM-Sport (p = .012), and posteromedial (p = .04) and posterolateral (p = .003) SEBT reach directions. No group main effect or time by group interaction was found. Four weeks of supervised rehabilitation improved self-reported function and dynamic balance in people with CAI.

Comparison of the effect of foot orthoses on Star Excursion Balance Test performance in patients with chronic ankle instability

2018 ◽  
Vol 43 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Faezeh Abbasi ◽  
Mahmood bahramizadeh ◽  
Mohammad Hadadi
Keyword(s):  
Ankle Sprain ◽  
Ankle Instability ◽  
Dynamic Balance ◽  
Chronic Ankle Instability ◽  
Textured Surface ◽  
Foot Orthoses ◽  
Textured Surfaces ◽  
Balance Test ◽  
Star Excursion Balance Test ◽  
Foot Orthosis

Background: Chronic ankle instability as a prevalent consequence of ankle sprain causes various impairments such as balance and postural control deficits. Foot orthoses are one of the common interventions for rehabilitation of patients with chronic ankle instability. Objectives: To investigate the effect of custom-molded foot orthoses with textured surfaces on dynamic balance of chronic ankle instability patients and to compare their effects with other types of foot orthoses. Study design: This is a repeated measure design. Methods: A total of 30 participants were recruited based on the guideline introduced by the International Ankle Consortium. The effect of prefabricated, custom-molded, and custom-molded with textured surface foot orthoses was evaluated on dynamic balance by the Star Excursion Balance Test. Normalized reach distances in anteromedial, medial, and posteromedial directions of the test were computed to be used for statistical analysis. Results: The foot orthoses increased reach distances compared to the no-orthosis conditions in all three directions. The custom-molded with textured surface foot orthosis has significant differences compared with prefabricated foot orthosis ( p = 0.001) in all measured directions and with custom-molded foot orthosis ( p < 0.01) in medial and posteromedial directions. Conclusion: Foot orthoses improve reach distances in patients with chronic ankle instability. Custom-molded with textured surface foot orthosis has a more pronounced effect compared with other foot orthoses. Clinical relevance The custom-molded foot orthosis with textured surface could be an effective device to improve dynamic balance in chronic ankle instability (CAI) patients. It may be considered as an efficient intervention to reduce ankle sprain recurrence in these individuals, although further research should be conducted.

Study on Single-Plane Biaxial Balance Monitor System in ULTRA-Precision Grinding

2006 ◽  
Vol 304-305 ◽  
pp. 251-255
Author(s):  
L. Zheng ◽  
Yin Biao Guo ◽  
Z.Z. Wang
Keyword(s):  
Mutual Influence ◽  
Machining Accuracy ◽  
Monitor System ◽  
Machining Parameters ◽  
Precision Grinding ◽  
Single Plane ◽  
Workpiece Surface ◽  
Surface Error ◽  
Vibration Data ◽  
Ultra Precision

This paper puts forward an intelligent single-plane biaxial balance monitor system, which is used in ultra-precision grinding. It adopts the method of single-plane balance correction for the vibration of wheel and workpiece. And this system can also be used for integral balance. For ultra-precision grinding, caused by the mutual influence of the vibration of wheel and workpiece, there will be a ripple on the workpiece surface, which is mainly influenced by the frequency ratio of wheel to workpiece, the feed rate and the vibration of wheel and workpiece. This system can improve the machining accuracy, reduce the surface error of workpiece and appraise the integrated machining result, by analyzing the vibration data of wheel and workpiece and adjusting machining parameters.

Dynamic Characteristics Analysis for the Headstock of a Vertical Machining Center

2016 ◽  
Vol 836-837 ◽  
pp. 348-358
Author(s):  
Zhe Li ◽  
Song Zhang ◽  
Yan Chen ◽  
Peng Wang ◽  
Ai Rong Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Numerical Control ◽  
Vibration Test ◽  
Machining Accuracy ◽  
Modal Test ◽  
Machining Center ◽  
Characteristics Analysis ◽  
Nc Machine

Dynamic characteristics of numerical control (NC) machine tools, such as natural frequency and vibration property, directly affect machining efficiency and finished surface quality. In general, low-order natural frequencies of critical components have significant influences on machine tool’s performances. The headstock is the most important component of the machine tool. The reliability, cutting stability, and machining accuracy of a machining center largely depend on the structure and dynamic characteristics of the headstock. First, in order to obtain the natural frequencies and vibration characteristics of the headstock of a vertical machining center, modal test and vibration test in free running and cutting conditions were carried out by means of the dynamic signal collection and analysis system. According to the modal test, the first six natural frequencies of the headstock were obtained, which can not only guide the working speed, but also act as the reference of structural optimization aiming at frequency-shift. Secondly, by means of the vibration test, the vibration characteristics of the headstock were obtained and the main vibration sources were found out. Finally the corresponding vibration reduction plans were proposed in this paper. That provides the reference for improving the performance of the overall unit.

An on-machine error compensation method for an ultra-precision turning machine

2017 ◽  
Vol 233 (5) ◽  
pp. 1608-1613
Author(s):  
Xicong Zou ◽  
Xuesen Zhao ◽  
Guo Li ◽  
Zengqiang Li ◽  
Zhenjiang Hu ◽  
...  
Keyword(s):  
Error Compensation ◽  
Rapid Development ◽  
Compensation Method ◽  
Machining Accuracy ◽  
Manufacturing Cost ◽  
Program Code ◽  
Machine Error ◽  
Measurement Results ◽  
Ultra Precision ◽  
Compensation Technique

On-machine error compensation (OMEC) is efficient at improving machining accuracy without increasing extra manufacturing cost, and involves the on-machine measurement (OMM) of machining accuracy and modification of program code based on the measurement results. As an excellent OMM technique, chromatic confocal sensing allows for the rapid development of accurate and reliable error compensation technique. The present study integrated a non-contact chromatic confocal probe into an ultra-precision machine for OMM and OMEC of machined components. First, the configuration and effectiveness of the OMM system were briefly described, and the relevant OMEC method was presented. With the OMM result, error compensation software was then developed to automatically generate a modified program code for error compensation. Finally, a series of cutting experiments were performed to verify the validity of the proposed OMEC method. The experimental results demonstrate that the proposed error compensation method is reliable and considerably improves the form error of machined components.

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