【摘要】：本文所研究的新型并聯(lián)工作臺(tái)在空間內(nèi)有兩個(gè)移動(dòng)自由度及兩個(gè)轉(zhuǎn)動(dòng)自由度，，可以與銑、鏜、加工中心等機(jī)床組合使用，能夠完成對零空間件任意角度平面及孔的加工要求。本文對該并聯(lián)工作臺(tái)的自由度分析、運(yùn)動(dòng)學(xué)、靜力學(xué)及靜動(dòng)態(tài)特性等進(jìn)行了研究和探討。 本文首先介紹了并聯(lián)機(jī)構(gòu)的國內(nèi)外研究現(xiàn)狀，敘述了本文所要研究的并聯(lián)工作臺(tái)的設(shè)計(jì)目的。接著，采用螺旋理論分析四自由度并聯(lián)工作臺(tái)的自由度的數(shù)目及性質(zhì)。然后，對并聯(lián)工作臺(tái)進(jìn)行了位置分析，利用解析法給出該并聯(lián)工作臺(tái)的位置反解，采用數(shù)值方法中的牛頓下山法求取了該并聯(lián)工作臺(tái)的位置正解，并利用反解驗(yàn)證了正解的正確性。利用求導(dǎo)法和螺旋法分別求取了并聯(lián)工作臺(tái)的速度雅可比矩陣，得到了并聯(lián)工作臺(tái)各支鏈輸入速度與動(dòng)平臺(tái)輸出速度之間的關(guān)系，且進(jìn)行了奇異性分析。研究了該并聯(lián)工作臺(tái)的靜力學(xué)。利用雅可比矩陣，運(yùn)用虛功原理求得了動(dòng)平臺(tái)所受外力和外力矩到驅(qū)動(dòng)關(guān)節(jié)的運(yùn)動(dòng)關(guān)系。并通過雅可比矩陣方便的求得了并聯(lián)工作臺(tái)的剛度矩陣。對并聯(lián)工作臺(tái)有限元模型的建立過程進(jìn)行了研究，選取了并聯(lián)工作臺(tái)的5種極限位姿，建立了精確有限元模型。在有限元模型的基礎(chǔ)上，對并聯(lián)工作臺(tái)進(jìn)行了靜力特性分析，考察了在工作載荷下，并聯(lián)工作臺(tái)在五種極限位姿處的應(yīng)力和變形特點(diǎn)。運(yùn)用有限元軟件動(dòng)態(tài)特性分析功能，對并聯(lián)工作臺(tái)進(jìn)行了模態(tài)分析，根據(jù)分析結(jié)果，找出工作臺(tái)的薄弱環(huán)節(jié)，并總結(jié)并聯(lián)工作臺(tái)的動(dòng)態(tài)特性。對一般鉆孔空過程中由鉆削力引起的諧響應(yīng)進(jìn)行研究，找出了在鉆孔過程中應(yīng)避開的頻率范圍。 對于機(jī)構(gòu)自由度的分析，傳統(tǒng)上采用CGK公式計(jì)算其自由度數(shù)目，而自由度性質(zhì)只能靠研究者的經(jīng)驗(yàn)判斷。本文采用螺旋理論分析該并聯(lián)工作臺(tái)的自由度，不僅計(jì)算了其自由度的數(shù)目，而且準(zhǔn)確給出了自由度的性質(zhì)。由于并聯(lián)工作臺(tái)動(dòng)平臺(tái)可以運(yùn)動(dòng)，不同位姿其靜動(dòng)態(tài)特性不同，為了研究工作臺(tái)的靜動(dòng)特性，故選取了工作臺(tái)的5個(gè)極限位姿，分別分析并聯(lián)工作臺(tái)在5種極限位姿下的靜動(dòng)特性，找出了工作臺(tái)的薄弱環(huán)節(jié)以及并聯(lián)工作臺(tái)在鉆孔時(shí)應(yīng)該避開的頻率范圍。
[Abstract]:The new parallel worktable studied in this paper has two degrees of freedom of movement and two degrees of freedom of rotation in space, which can be used in combination with milling, boring, machining center and other machine tools, and can fulfill the machining requirements of any angle plane and hole of zero space parts. In this paper, the degree of freedom analysis, kinematics, statics and static and dynamic characteristics of the parallel table are studied and discussed. This paper first introduces the research status of parallel mechanism at home and abroad, and describes the design purpose of the parallel table to be studied in this paper. Then, the helical theory is used to analyze the number and properties of the four-DOF parallel worktable. Then, the position of the parallel table is analyzed, the inverse solution of the parallel table is given by using the analytic method, and the positive solution of the position of the parallel table is obtained by Newton's downhill method in the numerical method. The correctness of the positive solution is verified by the inverse solution. The velocity Jacobian matrix of the parallel table is obtained by using the derivation method and the spiral method. The relationship between the input speed of each branch chain and the output velocity of the moving platform is obtained, and the singularity analysis is carried out. The statics of the parallel table is studied. By using Jacobian matrix and the principle of virtual work, the motion relationship between the driving joint and the external force and moment of the moving platform is obtained. The stiffness matrix of parallel table is obtained conveniently by Jacobian matrix. The process of establishing the finite element model of parallel worktable is studied. Five kinds of limit positions of parallel worktable are selected and the accurate finite element model is established. Based on the finite element model, the static characteristics of the parallel table are analyzed, and the stress and deformation characteristics of the parallel table at five kinds of extreme positions are investigated under the working load. The modal analysis of the parallel worktable is carried out by using the dynamic characteristic analysis function of the finite element software. According to the analysis results, the weak links of the worktable are found out, and the dynamic characteristics of the parallel worktable are summarized. The harmonic response caused by drilling force in the general borehole process is studied and the frequency range that should be avoided in the drilling process is found out. For the analysis of the degree of freedom of the mechanism, the number of degrees of freedom is traditionally calculated by the CGK formula, and the nature of the degree of freedom can only be judged by the experience of the researcher. In this paper, the degree of freedom of the parallel table is analyzed by spiral theory. Not only the number of degrees of freedom is calculated, but also the property of the degree of freedom is given accurately. In order to study the static and dynamic characteristics of the parallel worktable, five limit positions are selected for studying the static and dynamic characteristics of the parallel worktable, because the moving platform of the parallel worktable can move and the static and dynamic characteristics of the platform are different from each other. The static and dynamic characteristics of the parallel table under five kinds of extreme positions are analyzed respectively. The weak links of the parallel table and the frequency range of the parallel table should be avoided when drilling holes are found out.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：TH113

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 彭禮斌;2-PRS/2-UPS四自由度并聯(lián)工作臺(tái)工作精度研究[D];蘭州理工大學(xué);2013年

本文編號(hào)：2347325