閥—泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng)研究
本文關(guān)鍵詞: 補油式閥-泵并聯(lián)控制 泄油式閥-泵并聯(lián)控制 變結(jié)構(gòu) 調(diào)速系統(tǒng) 閥-泵權(quán)重比 綜合性能 虛擬儀器 出處:《中國礦業(yè)大學(xué)》2014年博士論文 論文類型:學(xué)位論文
【摘要】:傳統(tǒng)的液壓馬達調(diào)速系統(tǒng)有兩種基本形式:閥控和泵控。閥控響應(yīng)快但效率低,適用于對快速性要求較高的中小功率場合;泵控效率高但響應(yīng)慢,適用于大功率和對快速性要求不高的場合。近年來,閥-泵聯(lián)合控制得到了迅速發(fā)展,其充分發(fā)揮了閥控與泵控各自的優(yōu)勢。論文提出了一種嶄新的閥-泵并聯(lián)控制系統(tǒng),即閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng),在調(diào)速過程中控制模式隨控制要求而變,可實現(xiàn)大功率液壓調(diào)速系統(tǒng)的綜合性能,即低速平穩(wěn)快速啟停、快速調(diào)節(jié)負載干擾、全程高效率。 論文的主要工作和研究成果如下: (1)總結(jié)和分析了國內(nèi)外目前閥-泵聯(lián)合控制系統(tǒng)的工作原理和特點,并指出目前的閥-泵聯(lián)合控制方式難以實現(xiàn)上述綜合性能。 (2)設(shè)計了閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng),其關(guān)鍵點有兩點,一是閥可以根據(jù)控制要求處于補油或泄油兩種狀態(tài),以使系統(tǒng)處于補油或泄油式閥-泵并聯(lián)兩種控制模式,二是可以通過改變Kvp,調(diào)節(jié)閥控與泵控在速度控制中的比重;建立了閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng)的數(shù)學(xué)模型,分析了系統(tǒng)的參數(shù),并指出傳統(tǒng)的泵控系統(tǒng)加入閥控后,液壓固有頻率不變,但總泄漏系數(shù)明顯增大,導(dǎo)致系統(tǒng)阻尼比顯著增大且隨閥的工作點(閥開口及系統(tǒng)壓力)而變化,同時導(dǎo)致系統(tǒng)剛度下降,易受負載干擾。 (3)設(shè)計了開式以及閉式閥-泵并聯(lián)變結(jié)構(gòu)控制系統(tǒng)的結(jié)構(gòu),建立了補油式和泄油式閥-泵并聯(lián)控制閉式系統(tǒng)的流量平衡方程,分析了各流量之間的關(guān)系,指出在閉式閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng)中,補油回路及沖洗回路是必需的,不能因有閥控補油就取消補油回路,同時沖洗回路除了有熱交換的作用還有平衡系統(tǒng)流量的作用。建立了液壓模擬系統(tǒng)與實際系統(tǒng)之間參數(shù)匹配的理論基礎(chǔ),指出為模擬實際系統(tǒng)的動態(tài)特性,應(yīng)分別按照泵排量、馬達排量、轉(zhuǎn)動慣量三個參數(shù)來配置模擬系統(tǒng),本實驗系統(tǒng)是以煤礦液壓提升機這種大功率大慣量液壓系統(tǒng)為例而建立的模擬系統(tǒng)。 (4)提出了閥控權(quán)重Kv和泵控權(quán)重Kp的概念,并依據(jù)不同的Kv和Kp,建立了傳統(tǒng)泵控、閥控與閥-泵并聯(lián)控制之間的聯(lián)系;為了判別閥與泵在聯(lián)合調(diào)速中的作用,建立了閥-泵權(quán)重比的概念,即Kvp=Kv:Kp,并通過該權(quán)重比以及閥控狀態(tài),判別系統(tǒng)處于何種控制模式。 (5)提出了補油式和泄油式閥-泵并聯(lián)兩種控制模式,研究了不同權(quán)重比對控制特性的影響,并獲得了閥-泵并聯(lián)控制的規(guī)律:在不同的權(quán)重比(Kvp=1:0~0:1)下,系統(tǒng)響應(yīng)速度呈金字塔形,兩頭慢(閥控和泵控),中間快(閥-泵并聯(lián)控制),因此無論對于指令信號,還是負載干擾的快速響應(yīng),閥-泵并聯(lián)控制比單獨泵控或閥控響應(yīng)都快;因閥控的開環(huán)增益大于泵控,對于相同的權(quán)重之和(Kv+Kp),,以閥控為主的系統(tǒng)響應(yīng)快于以泵控為主;閥與泵的流量之比與閥-泵權(quán)重比成正比;補油式比泄油式閥-泵并聯(lián)控制更具優(yōu)勢,因為前者使系統(tǒng)的阻尼比更穩(wěn)定,這有利于系統(tǒng)的預(yù)測與控制,并且還可通過提高Ps,進一步提高響應(yīng)速度和增大速度剛度,更適用于對負載干擾的快速調(diào)節(jié),仿真與實驗結(jié)果表明,此處取Kvp=1:0.2較合適。 (6)研究了不同控制模式下大慣量系統(tǒng)的低速特性。泄油式閥控或泄油式并聯(lián)閥控通過增加可控的泄漏,增大系統(tǒng)的阻尼比,以增強低速平穩(wěn)性,而且由閥控泄漏引起的阻尼比的增加,可補償因摩擦負斜率(Stribeck效應(yīng))引起的阻尼比的下降,進一步增強了系統(tǒng)的低速穩(wěn)定性。閥初始電壓對提高低速特性至關(guān)重要,建立了閥初始電壓的理論公式,并研究了不同油溫,不同開口對系統(tǒng)低速特性的影響,獲得了泄油式閥控在啟停低速階段的控制規(guī)律,同時實驗表明,只要閥初始電壓設(shè)置在理論值附近,均能獲得滿意的低速特性,這使泄油式閥控具有操作性和實用性,且此處取Kvp=1:0.1較合適。 (7)建立了閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速系統(tǒng)的AMEsim仿真模型以及基于虛擬儀器技術(shù)的實驗系統(tǒng),研究了一個調(diào)速周期內(nèi)的閥-泵并聯(lián)變結(jié)構(gòu)調(diào)速特性。仿真與實驗結(jié)果表明,在調(diào)速過程中,不同控制模式之間切換平滑連續(xù),閥和泵的工作狀態(tài)符合預(yù)期;通過改變不同調(diào)速階段的控制模式,實現(xiàn)了大功率液壓馬達調(diào)速系統(tǒng)的綜合性能,即在低速段采用泄油式并聯(lián)閥控,實現(xiàn)了大慣量的平穩(wěn)快速啟停,在高速段采用補油式并聯(lián)閥控,實現(xiàn)了對負載干擾的快速調(diào)節(jié),在加速和減速段泵提供主要流量,充分了發(fā)揮泵控的高效的優(yōu)勢。 閥-泵并聯(lián)變結(jié)構(gòu)控制,利用閥控及泵控雙通道,建立了控制結(jié)構(gòu)(模式)依控制要求而變的靈活的控制機制,通過改變閥-泵權(quán)重比,使閥控與泵控協(xié)調(diào)工作,充分發(fā)揮了閥控、泵控各自的優(yōu)勢,豐富了液壓系統(tǒng)的調(diào)速方式,使電液控制系統(tǒng)更具靈活性和適應(yīng)性,可實現(xiàn)大功率液壓調(diào)速系統(tǒng)的綜合性能,如低速平穩(wěn)快速啟停、快速調(diào)節(jié)負載干擾、全程高效率。
[Abstract]:The traditional hydraulic motor speed regulation system has two basic forms : valve control and pump control , the valve control response is fast but the efficiency is low , it is suitable for occasions with high speed requirement . The main work and research results of the thesis are as follows : ( 1 ) The working principle and characteristics of the current valve - pump joint control system at home and abroad are summarized and analyzed , and it is pointed out that the current valve - pump joint control mode is difficult to achieve the above - mentioned comprehensive performance . ( 2 ) The valve - pump parallel variable structure speed regulating system is designed . The key points are two points . One is that the valve can be in the two states of oil filling or oil drain according to the control requirements , so as to make the system be in the two control modes of feeding oil or oil drain valve - pump in parallel . The parameters of the system are analyzed , and it is pointed out that the traditional pump control system is changed with the valve control , the damping ratio of the system is obviously increased and the system damping ratio changes with the working point of the valve ( valve opening and system pressure ) , and the system rigidity is reduced , and the load interference is easy . ( 3 ) The structure of the open and closed valve - pump parallel variable structure control system is designed , the flow balance equation of the closed system is established , and the relationship between the flow rates is analyzed . It is pointed out that in the closed valve - pump parallel variable structure speed regulation system , the oil feeding circuit and the flushing circuit are necessary , and the simulation system can be configured according to three parameters of the pump displacement , the motor displacement and the moment of inertia in the closed valve - pump parallel variable structure speed regulation system . ( 4 ) The concept of valve - controlled weighting and pump - control weights is put forward , and the relation between traditional pump control , valve - control and parallel control of valve - pump is established according to different kinds of KV and KP . In order to judge the function of valve and pump in joint speed regulation , the concept of valve - pump weight ratio is established , that is , Kvp = KV : KP , and the control mode of the system is discriminated by the weight ratio and the valve control state . ( 5 ) The effect of different weight ratios on the control characteristics is studied , the effect of different weight ratios on the control characteristics is studied , and the valve - pump parallel control is faster than that of the valve - pump control . ( 6 ) The low - speed characteristics of the large inertia system in different control modes are studied . By increasing the controllable leakage , the damping ratio of the system can be increased by increasing the damping ratio of the system , so that the low - speed stability of the system is enhanced . ( 7 ) The simulation model of valve - pump parallel variable structure speed control system is established and the experiment system based on virtual instrument technology is established . The simulation and experimental results show that the switching between different control modes is consistent with the expectation in the process of speed regulation . By changing the valve - pump weight ratio , the valve control and pump control coordination work is established , the valve control and the pump control coordination work are fully exerted , the speed regulation mode of the hydraulic system is fully exerted , the comprehensive performance of the high - power hydraulic speed regulation system can be realized , such as low - speed smooth start - stop , rapid adjustment of load interference and full - process efficiency .
【學(xué)位授予單位】:中國礦業(yè)大學(xué)
【學(xué)位級別】:博士
【學(xué)位授予年份】:2014
【分類號】:TH137.51
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