本文關鍵詞：雙噴嘴擋板伺服閥流固耦合特性分析及振動抑制　出處：《北京交通大學》2015年博士論文　論文類型：學位論文

  更多相關文章： 電液伺服閥 流固耦合振動 自激振蕩 啟閉優(yōu)化

【摘要】：摘要：電液伺服系統(tǒng)以傳遞功率大、響應速度快、控制精度高等特點,在航空、航天、船舶等國防工業(yè)領域占有舉足輕重的地位。作為電液伺服控制系統(tǒng)中的核心部件,精密電液伺服閥機械結構復雜、精密度高,其自身穩(wěn)定性、可靠性和快速性很大程度上決定了電液伺服系統(tǒng)的控制性能,甚至影響到航空航天飛行任務的成敗。當進行啟閉控制動作時,電液伺服系統(tǒng)內部流體激振常常產生自激現(xiàn)象,導致力矩馬達及活塞產生較大的振動幅值,嚴重影響其正常工作特性甚至使用壽命。本文以某型航天用精密雙噴嘴擋板電液伺服閥為研究對象,對電液伺服閥的流固耦合振動特性、誘發(fā)機理以及對整個系統(tǒng)控制的影響規(guī)律進行深入研究,以便構造合理的基礎模型,進一步完善電液伺服閥基礎理論體系,最后獲取相應的控制措施來減小或抑制耦合振動。 本文首先闡述本課題的研究背景,總結了國內外學者在流固耦合振動特性、研究方法、電液伺服系統(tǒng)振動的研究概況以及振動控制等方面的研究成果,分析并提出了流固耦合振動分析及控制中的關鍵問題,明確本文的研究方向、目的及意義,最后確定本文研究的技術路線。 根據(jù)閥控電液伺服控制系統(tǒng)的基本工作原理,對電液伺服閥的靜動態(tài)特性進行了深入分析,建立了雙噴嘴擋板伺服閥的非線性數(shù)學模型,同時根據(jù)非線性微分控制理論,通過非線性狀態(tài)反饋變換,將系統(tǒng)進行輸入／輸出線性化,并在此基礎上對系統(tǒng)的零動態(tài)穩(wěn)定性進行了深入分析。相較于基于工作點的基礎增量線性化方法而言,所建的線性化數(shù)學模型將為分析流固耦合振動現(xiàn)象以及振動控制提供理論基礎,新模型將更接近實際控制系統(tǒng)。 伺服閥自激是由系統(tǒng)的非恒定流動引起,是流動參數(shù)階躍變化時的動態(tài)過渡過程。電液伺服閥以噴嘴擋板為前置級驅動結構,其內部噴嘴射流流動速度快、剪切流動強、析出氣穴多,流體激振引起的耦合振動往往造成伺服閥工作中產生高頻嘯叫。在本文中,結合流體力學的基本理論,以非線性電液伺服閥模型為基礎,建立了噴嘴擋板間射流流場模型。同時通過現(xiàn)場試驗,獲取電液伺服閥射流流場的真實流動參數(shù),最終給出前置級射流壓力脈動、結構參數(shù)與高頻自激振動三者之間的內在聯(lián)系。 伺服閥滑閥副組件作為伺服閥二級放大結構,流體通過閥口高速流入相對緩慢的閥腔流場中,形成具有較大速度梯度的自由剪切層,剪切分離處的微小擾動在傳播過程中受剪切層不穩(wěn)定性影響形成放大,并遞經上下游壁反射誘發(fā)新的擾動,形成自激振動。本文采用流體振蕩理論及流體行為方程數(shù)值方法,將流經管道的流體作為非線性參數(shù)系統(tǒng),計算出各處的閥或者執(zhí)行元件,當作流體運動的邊界條件,計算了穩(wěn)定界限,獲得了方程組的精確解,最后基于其結構特點和工作特性的分析,提出了一種流固耦合半解析式數(shù)學模型。為了深入研究液壓系統(tǒng)的運動狀態(tài)和各項參數(shù)的分布規(guī)律,根據(jù)液壓系統(tǒng)運動的實際情況和運動過程,以一維流體瞬變理論為基礎,考慮油液壓縮性對油液動量的改變,采用特征線分析方法,利用有限差分格式,對伺服閥控液壓管路關機水擊的進行數(shù)值分析,同時通過實驗研究獲取其管路動態(tài)特性,結果分析表明,該動態(tài)模型可以較好的描述管路系統(tǒng)的瞬變特性。 最后通過研發(fā)電液伺服自激特性研究試驗臺,對其靜動態(tài)以及流固耦合振動特性進行了實驗研究。結果表明,通過輸入/輸出線性化理論所建立的數(shù)學模型,可以有效地判別系統(tǒng)穩(wěn)定性,同時獲取輸入電流與閥芯輸出位移的關系；利用流固耦合振動模型,可以有效地解釋伺服閥高頻自激原理,通過實驗采集及數(shù)據(jù)分析得到的伺服閥自激頻率及幅值變化趨勢與計算結果基本一致,驗證了耦合振動模型的準確性；同時通過優(yōu)化Logistic方程曲線得到閥的優(yōu)化啟閉規(guī)律,有效的降低了電液伺服閥油液振動幅值,驗證了控制措施的有效性。
[Abstract]:Abstract: the electro-hydraulic servo system with large transmission power, fast response speed, control characteristics, high precision in the aviation, aerospace, shipbuilding and other plays an important role in defense industries. As the core component of electro-hydraulic servo control system of electro-hydraulic servo valve, precision mechanical structure is complex, high precision, its stability, reliability rapid and largely determines the control performance of the electro-hydraulic servo system, and even affect the aerospace mission success. When opening and closing control action, the electro-hydraulic servo system of internal fluid vibration often produce self-excited phenomenon, resulting in a torque motor and the piston to produce larger vibration amplitude, seriously affect the normal work the characteristics of life. Even in a certain type of Aerospace Precision two nozzlebaffle electro-hydraulic servo valve as the research object in this paper, the vibration characteristics of the electro-hydraulic servo valve and the mechanism induced by fluid solid coupling The influence rule of the whole system control is studied in depth, in order to construct a reasonable basic model and further improve the basic theory system of electro-hydraulic servo valve, and finally get the corresponding control measures to reduce or suppress the coupling vibration.
This paper first describes the research background, summarizes the domestic and foreign scholars in the liquid-solid coupling vibration characteristics, research methods, research results of electric hydraulic servo system of the vibration and vibration control, analysis and put forward the key flow problem analysis and control of the coupled vibration in the solid, clear the research direction, objective and the significance, finally determine the technical route of this study.
According to the basic principle of the valve control of the electro-hydraulic servo control system, the static and dynamic characteristics of electro-hydraulic servo valve were analyzed, a nonlinear mathematical model of the double nozzle flapper servo valve, and according to the nonlinear differential control theory, the nonlinear state feedback transformation, the system input / output linearization, and on this basis analyzed the stability of the zero dynamics system. Compared with the linear method based on the basis of the incremental operating point, the linear mathematical model built for analysis of fluid solid coupling vibration and vibration control to provide a theoretical basis, the new model will be closer to the actual control system.
Self servo valve is caused by unsteady flow system, is the dynamic flow parameters of the step change of electro-hydraulic servo valve with nozzle flapper for prestage structure, flow velocity within the nozzle jet, shear flow, precipitation of cavitation, the coupled vibration of fluid induced vibration caused by high frequency often cause Xiao servo valve work is produced. In this paper, combined with the basic theory of fluid mechanics, the nonlinear electro-hydraulic servo valve model as the foundation, established between the flapper nozzle jet flow field model. At the same time through the field test, the actual flow parameters of electro-hydraulic servo valve flow, finally gives the jet pressure pulsation, internal relationship between structure parameters and high frequency self-excited vibration of the three.
Servo valve assembly as servo valve two stage structure, the fluid through the valve port into the valve cavity flow speed relatively slow, the formation of the free shear layer has a larger velocity gradient, the shear separation perturbation in the propagation process by the shear layer instability effects formed by amplification, and passed on the downstream wall the new induced disturbance, formation of self-excited vibration. This paper uses numerical methods on fluid oscillation theory and fluid behavior equation, will flow through the pipeline fluid as a nonlinear system, calculated around the valve or actuator, as the motion of the fluid boundary conditions, the stability limit calculation, we obtain exact solutions of equations, based on analysis of the the structure characteristics and work characteristics, proposes a coupled semi analytic mathematical model. The distribution in order to further study the motion state of the hydraulic system and the parameters of the, According to the actual situation and the movement of the hydraulic system of motion, on the one-dimensional fluid transient theory, considering the change of oil compression on the oil momentum, using the characteristic analysis method, finite difference scheme, numerical analysis of servo valve controlled hydraulic pipeline water hammer, and obtain the dynamic characteristics of tubing through experimental research, results show that the characteristics of the dynamic model can describe the pipeline system better transient.
Finally, through the development of electro hydraulic servo test bench of self-excited characteristics, vibration characteristics of the static and dynamic flow experiments were carried out. The results show that the established mathematical model of input / output linearization theory, can effectively distinguish between system stability, while obtaining the input current and the output displacement of the valve core; the fluid solid the coupled vibration model can effectively explain the servo valve servo valve self high frequency principle, self excitation frequency and amplitude changes with the calculation results obtained by experimental analysis and data acquisition are basically the same, to verify the accuracy of the coupling vibration model and optimization; valve open shut law obtained by the optimization equation of Logistic curve, effectively reduces the power hydraulic servo valve oil vibration amplitude, verify the effectiveness of control measures.

【學位授予單位】：北京交通大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TH137;TB535

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本文編號：1432443