絲杠動(dòng)態(tài)剛度怎么測(cè)
來源:http://m.kezhirui.com/ 日期:2025-05-12 發(fā)布人:
在機(jī)械制造與自動(dòng)化領(lǐng)域,絲杠作為實(shí)現(xiàn)直線運(yùn)動(dòng)的核心傳動(dòng)部件,廣泛應(yīng)用于數(shù)控機(jī)床、工業(yè)機(jī)器人、精密儀器等設(shè)備中。絲杠的動(dòng)態(tài)剛度直接影響著機(jī)械系統(tǒng)的運(yùn)動(dòng)精度、穩(wěn)定性和可靠性。當(dāng)絲杠在動(dòng)態(tài)載荷作用下工作時(shí),若其動(dòng)態(tài)剛度不足,可能導(dǎo)致運(yùn)動(dòng)部件產(chǎn)生振動(dòng)、位移誤差,進(jìn)而影響整個(gè)設(shè)備的加工精度和使用壽命。因此,準(zhǔn)確測(cè)量絲杠的動(dòng)態(tài)剛度,對(duì)于優(yōu)化設(shè)計(jì)、保障設(shè)備性能關(guān)重要。
In the field of mechanical manufacturing and automation, screw as the core transmission component for achieving linear motion is widely used in CNC machine tools, industrial robots, precision instruments and other equipment. The dynamic stiffness of the screw directly affects the motion accuracy, stability, and reliability of the mechanical system. When the screw operates under dynamic loads, if its dynamic stiffness is insufficient, it may cause vibration and displacement errors in the moving parts, which in turn affect the machining accuracy and service life of the entire equipment. Therefore, accurately measuring the dynamic stiffness of the screw is crucial for optimizing design and ensuring equipment performance.
一、絲杠動(dòng)態(tài)剛度測(cè)量原理
1、 Principle of measuring dynamic stiffness of screw
絲杠的動(dòng)態(tài)剛度是指在動(dòng)態(tài)載荷作用下,絲杠抵抗變形的能力,通常用單位位移變化所對(duì)應(yīng)的動(dòng)態(tài)力來表示。其測(cè)量原理基于動(dòng)力學(xué)方程,當(dāng)對(duì)絲杠施加一個(gè)動(dòng)態(tài)激勵(lì)力時(shí),絲杠會(huì)產(chǎn)生相應(yīng)的振動(dòng)響應(yīng),通過測(cè)量激勵(lì)力和響應(yīng)位移,根據(jù)力學(xué)關(guān)系即可計(jì)算出動(dòng)態(tài)剛度。
The dynamic stiffness of a screw refers to its ability to resist deformation under dynamic loads, usually expressed in terms of the dynamic force corresponding to a unit displacement change. The measurement principle is based on dynamic equations. When a dynamic excitation force is applied to the screw, the screw will produce corresponding vibration response. By measuring the excitation force and response displacement, the dynamic stiffness can be calculated based on the mechanical relationship.
從本質(zhì)上來說,絲杠可視為一個(gè)復(fù)雜的彈性振動(dòng)系統(tǒng),其動(dòng)態(tài)特性受到自身結(jié)構(gòu)參數(shù)(如直徑、長(zhǎng)度、導(dǎo)程)、材料屬性(彈性模量、密度)以及工作條件(轉(zhuǎn)速、潤(rùn)滑狀態(tài))等多種因素的影響。在動(dòng)態(tài)測(cè)量過程中,需要考慮這些因素對(duì)測(cè)量結(jié)果的綜合作用,以獲取準(zhǔn)確可靠的動(dòng)態(tài)剛度數(shù)據(jù)。
Essentially, the screw can be regarded as a complex elastic vibration system, whose dynamic characteristics are influenced by various factors such as its own structural parameters (such as diameter, length, lead), material properties (elastic modulus, density), and working conditions (speed, lubrication state). In the process of dynamic measurement, it is necessary to consider the comprehensive effect of these factors on the measurement results in order to obtain accurate and reliable dynamic stiffness data.
二、常用的絲杠動(dòng)態(tài)剛度測(cè)量方法
2、 Common methods for measuring the dynamic stiffness of lead screws
?。ㄒ唬┘ふ穹?/p>
?。?) Excitation method
激振法是一種較為常用的測(cè)量絲杠動(dòng)態(tài)剛度的方法。該方法通過對(duì)絲杠施加特定頻率和幅值的激振力,使其產(chǎn)生受迫振動(dòng)。常用的激振設(shè)備有激振器、力錘等。
Excitation method is a commonly used method for measuring the dynamic stiffness of lead screws. This method applies a specific frequency and amplitude of excitation force to the screw to induce forced vibration. Common vibration excitation equipment includes exciters, force hammers, etc.
以激振器為例,將激振器與絲杠剛性連接,通過控制系統(tǒng)調(diào)節(jié)激振器輸出不同頻率的正弦激勵(lì)力。同時(shí),在絲杠上安裝位移傳感器(如激光位移傳感器、電容式位移傳感器),實(shí)時(shí)測(cè)量絲杠在激振力作用下的位移響應(yīng)。利用數(shù)據(jù)采集系統(tǒng)記錄激勵(lì)力信號(hào)和位移響應(yīng)信號(hào),通過傅里葉變換等信號(hào)處理方法,將時(shí)域信號(hào)轉(zhuǎn)換為頻域信號(hào),進(jìn)而分析絲杠在不同頻率下的動(dòng)態(tài)剛度特性。
Taking the exciter as an example, the exciter is rigidly connected to the screw, and the exciter outputs sinusoidal excitation forces of different frequencies through the control system. At the same time, displacement sensors (such as laser displacement sensors and capacitive displacement sensors) are installed on the lead screw to measure the displacement response of the lead screw under excitation force in real time. Using a data acquisition system to record excitation force signals and displacement response signals, the time-domain signals are converted into frequency-domain signals through signal processing methods such as Fourier transform, and the dynamic stiffness characteristics of the screw at different frequencies are analyzed.
激振法能夠地獲取絲杠在寬頻范圍內(nèi)的動(dòng)態(tài)剛度數(shù)據(jù),適用于對(duì)絲杠動(dòng)態(tài)性能進(jìn)行深入研究和分析。但該方法需要的激振設(shè)備和信號(hào)處理系統(tǒng),測(cè)量成本較高,且對(duì)測(cè)量環(huán)境要求較為嚴(yán)格,需盡量避免外界振動(dòng)干擾。
The excitation method can comprehensively obtain the dynamic stiffness data of the screw over a wide frequency range, and is suitable for in-depth research and analysis of the dynamic performance of the screw. However, this method requires professional excitation equipment and signal processing systems, with high measurement costs and strict requirements for the measurement environment. It is necessary to avoid external vibration interference as much as possible.
?。ǘ┠B(tài)分析法
?。?) Modal analysis method
模態(tài)分析法基于結(jié)構(gòu)動(dòng)力學(xué)理論,通過對(duì)絲杠進(jìn)行模態(tài)試驗(yàn),獲取其固有頻率、振型等模態(tài)參數(shù),進(jìn)而推算出動(dòng)態(tài)剛度。在試驗(yàn)過程中,對(duì)絲杠進(jìn)行自由振動(dòng)或錘擊激勵(lì),使其產(chǎn)生振動(dòng)響應(yīng)。利用多個(gè)加速度傳感器布置在絲杠的不同位置,采集振動(dòng)加速度信號(hào)。
Modal analysis method is based on structural dynamics theory. By conducting modal tests on the screw, its natural frequency, vibration mode and other modal parameters are obtained, and the dynamic stiffness is then calculated. During the experiment, the lead screw is first subjected to free vibration or hammering excitation to generate vibration response. Multiple acceleration sensors are arranged at different positions on the screw to collect vibration acceleration signals.
通過對(duì)采集到的信號(hào)進(jìn)行分析,運(yùn)用模態(tài)參數(shù)識(shí)別算法(如頻域分解法、隨機(jī)子空間法等),提取絲杠的模態(tài)參數(shù)。根據(jù)模態(tài)參數(shù)與動(dòng)態(tài)剛度之間的關(guān)系,結(jié)合絲杠的結(jié)構(gòu)模型,計(jì)算出絲杠在不同工況下的動(dòng)態(tài)剛度。
By analyzing the collected signals and using modal parameter identification algorithms such as frequency domain decomposition and random subspace method, the modal parameters of the screw are extracted. Based on the relationship between modal parameters and dynamic stiffness, combined with the structural model of the screw, calculate the dynamic stiffness of the screw under different working conditions.
模態(tài)分析法不需要施加復(fù)雜的動(dòng)態(tài)激勵(lì),測(cè)量過程相對(duì)簡(jiǎn)單,且能夠反映絲杠的固有動(dòng)態(tài)特性。但該方法依賴于精確的結(jié)構(gòu)建模和模態(tài)參數(shù)識(shí)別技術(shù),若模型不準(zhǔn)確或識(shí)別算法存在誤差,可能導(dǎo)致測(cè)量結(jié)果偏差較大。
Modal analysis method does not require complex dynamic excitation, the measurement process is relatively simple, and it can reflect the inherent dynamic characteristics of the screw. However, this method relies on precise structural modeling and modal parameter identification techniques. If the model is inaccurate or the identification algorithm has errors, it may lead to significant measurement result deviations.
(三)工作狀態(tài)測(cè)量法
?。?) Work state measurement method
工作狀態(tài)測(cè)量法是在絲杠實(shí)際工作過程中,實(shí)時(shí)測(cè)量其動(dòng)態(tài)剛度。該方法通過在絲杠驅(qū)動(dòng)系統(tǒng)中安裝力傳感器和位移傳感器,直接獲取絲杠在工作載荷作用下的力和位移數(shù)據(jù)。例如,在數(shù)控機(jī)床的進(jìn)給系統(tǒng)中,將力傳感器安裝在絲杠與螺母之間,測(cè)量工作時(shí)的軸向力;同時(shí),利用光柵尺等位移測(cè)量裝置監(jiān)測(cè)絲杠的位移變化。
The working state measurement method is to measure the dynamic stiffness of the screw in real time during its actual working process. This method directly obtains the force and displacement data of the screw under working load by installing force sensors and displacement sensors in the screw drive system. For example, in the feed system of a CNC machine tool, a force sensor is installed between the screw and nut to measure the axial force during operation; At the same time, displacement measurement devices such as grating rulers are used to monitor the displacement changes of the screw.
根據(jù)測(cè)量得到的力和位移數(shù)據(jù),通過計(jì)算即可得到絲杠在實(shí)際工作狀態(tài)下的動(dòng)態(tài)剛度。工作狀態(tài)測(cè)量法能夠真實(shí)反映絲杠在實(shí)際工況下的動(dòng)態(tài)性能,對(duì)于評(píng)估設(shè)備運(yùn)行狀態(tài)和優(yōu)化控制策略具有重要意義。然而,該方法受到工作環(huán)境和工況的限制,測(cè)量數(shù)據(jù)的穩(wěn)定性和重復(fù)性可能較差,需要進(jìn)行多次測(cè)量和數(shù)據(jù)處理以提高測(cè)量精度。
Based on the measured force and displacement data, the dynamic stiffness of the screw under actual working conditions can be obtained through calculation. The working state measurement method can truly reflect the dynamic performance of the screw under actual working conditions, which is of great significance for evaluating equipment operating status and optimizing control strategies. However, this method is limited by the working environment and conditions, and the stability and repeatability of the measurement data may be poor, requiring multiple measurements and data processing to improve measurement accuracy.
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