【正文】 ler, a linearization process was used to reduce the nonlinearity errors. Many data points were inserted between a pair of NCcodes. The insertion of many data points caused the cutter position change to be nearly equal to zero while the cutter orientation changed abruptly. As a consequence, the machine rotary movements were rapid with infinite feedrate. Random rotary movements resulted and the workpiece was damaged. The insertion of machining data points can also cause nonconstant federate along the cutting curve. The insertion of additional data results in nonequally spaced segment, while acceleration and deceleration steps are required for each segment. Thus, the feederate varies in each segment and may never reach the desired value. The result of varying feederate causes a nonsmooth surface finish and the unreachable feedrate increases overall machining time. In addition, the insertion of constant cutter orientation variation also causes severe roughness around the end points along the surface. Linearly inaccurately since the change in cutter orientation is not necessarily linear. The nonlinearity error problem arises from the fact that fiveaxis machining motion trajectories are nonlinear curve segments. The simultaneous and coupled rotary and translation movements generate the nonlinearity motion trajectory, and the linear interpolation technique is not capable to curve fit the nonlinear path. One solution to is to design new interpolation methods. Liang et al.(2002)presented a bine 3D linear and circular (3D Lamp。2. Determine the CC point coordinates by employing the machine motion trajectory model。8. Modify the machine rotary angle change ifδmaxδa,n ,that is, increase or decreaseΔBm andΔCm such that the nonlinearity error, δn1, will satisfy (δn1δa,n)0。4. Computer the linearity error by using the formula given by Faux and Pratt(1979):δt =1/8 Kf (Δs)2where, Kfthe surface local curvature determined from step(3)。C interpolation can online drive the rotation movement pivot along a predesigned 3D curve path, so that the CC point motion trajectory is a via a straight line connecting machining data points, thus, the nonlinearity error can be eliminated. Fiveaxis machining movements are kinematically related to the cutter location data. In other word, the nonlinear motion trajectory depends on the cutter orientation changes and nonlinearity errors are related to the tool path generation. Thus, another solution to the nonlinearity error problem can be approached from tool path(CLDATA)generation with the requirements that the machining errors are minimized and there is no interference between the workpiece and the cutter. In tool path generation, various techniques for different surface representations have been used by the CAD/CAM package producers (CLDATA,1996。 Machining motion trajectory. INTRODUCTIONIn conventional fiveaxis machining, a tool path, represented by the cutter locations data (CLDATA), consists of the spatially varying cutter positions and its axis orientations. These CLDATA are generated based solely on the geometrical properties of the machined surfaces and the cutter. These CLDATA are further processed into NCcodes which is specific to a particular machine configuration. Linear interpolation is then used to generate the required mands for positions along line segment connecting the machining data points. The simultaneous linear and rotary movements are involved in fiveaxis machining since ever new cutter axis orientation requires the motion at least one other axis. There are also coupling effects of the cutter axis will affect the position of the cutter. These simultaneous and coupled movements cause the cutter contract point (CC point) to move in a nonlinear manner. As a result, the machining error in each motion step is made up of not only the linear segmentation approximation error but also an additional machining error. As shown in figure 1 for machining is either a concave surface or a convex surface, a line segment is used to connect two consecutive machining data points (the spindle chunk is the machine control point MCP). Linear interpolation generate intermediate positions along the line segment. The desire surface is design curve(either concave or convex). The linear segment approximates to design curve resulting in the linearity error,δt. Apart from the linearity error . The nonlinear CC point trajectory deviates from the straight line segment (the cutter gage length is constant and MCP is interpolated along the line segment)result in an additional machining error, referred to as the nonlinearity error, δn. In the case that the desire surface is concave(see figure 1a), the total machining error is difference of the nonlinearity error and the linearity error : δtotal=δtδn. The nonlinearity error, in this case, pensate for the total machining error(AIGP Postprocessor,1996。一種學(xué)機(jī)械就必須按照一定的標(biāo)準(zhǔn)來衡量一切事物的方法論。[14] 章躍，張國生．機(jī)械制造專業(yè)英語[M]．北京機(jī)械工業(yè)出版社，1999．12[15] 楊叔子 楊克沖． 機(jī)械工程控制基礎(chǔ) 第五版[M]．武漢：華中科技大學(xué)出版社，2005．7[16] 孫桓，陳作模，葛文杰. 機(jī)械原理 第七版[M]．北京：高等教育出版社2006．5[17] 李廣弟，朱月秀，[M].北京：北京航空航天大學(xué)出版社，[18] [M].北京：科學(xué)出版社，2004謝 辭本次設(shè)計(jì)是對自己大學(xué)四年來所學(xué)東西的一次總結(jié)，在設(shè)計(jì)中出現(xiàn)過許多的狀況，也從中學(xué)習(xí)了許多。北京機(jī)械工業(yè)出版社，1982[4] [M]，北京。驅(qū)動缸外徑及行程：按GB106867得D’=60mm；由GB234980選取缸的行程S=650mm。 調(diào)速閥：Q63B 。~ MPa，為一般液壓系統(tǒng)，液壓系統(tǒng)中固體顆粒的大小約為25~50μm選取的普通網(wǎng)式濾油器，裝在液壓泵的吸油管路上。兩泵可以通過溢流閥調(diào)定的壓力來控制。當(dāng)系統(tǒng)一些參數(shù)，特別是壓力，隨著工作條件的改變而發(fā)生大幅度的變化時，系統(tǒng)能夠取出適當(dāng)?shù)姆答佇盘?，即有條件采用反饋校正，是恰當(dāng)?shù)摹４藭r，系統(tǒng)按照一定的規(guī)律聯(lián)系相關(guān)的元素，通過信號的傳輸和交換。本設(shè)計(jì)采用蓄能器減少沖擊，當(dāng)液壓回路壓力升高時，蓄能器吸收能量，減少沖擊，實(shí)現(xiàn)緩沖。由于液壓缸充滿液壓油，故能從靜止到啟動較平穩(wěn)，且換向沖擊小，換向復(fù)位精準(zhǔn)。通過中間缸活塞二邊的運(yùn)動保持兩缸的流量基本相等。 調(diào)壓回路由于俯仰運(yùn)動采用的是雙聯(lián)同步運(yùn)動的液壓缸，因此要保證液壓缸以相同的位移和速度運(yùn)動。本機(jī)械手采用雙聯(lián)定量泵供油，用溢流閥來調(diào)定壓力，使系統(tǒng)在恒定的或限制的最高壓力下工作。cm2 = Kgcm2 ⑴試中：——步進(jìn)電機(jī)轉(zhuǎn)子轉(zhuǎn)動慣量(Kgcmd、計(jì)算步進(jìn)電機(jī)運(yùn)行頻率和最高起動頻率HzHz試中： ————最大切削進(jìn)給速度（m/min）。； ————電機(jī)——絲杠的傳動效率，為齒輪、軸承、絲杠效率之積。步距角，其中m為相繞組，z為轉(zhuǎn)子齒數(shù)，k為通電方式系數(shù)。3. 確定電動機(jī)的轉(zhuǎn)速。8X42X46X8二種類型的花鍵。因此，設(shè)計(jì)結(jié)構(gòu)簡單，定位可靠，軸上不需要開槽、鉆孔和切制螺紋，因此不影響軸的疲勞強(qiáng)度，而且結(jié)構(gòu)重量輕。軸選用的材料為45鋼，通過調(diào)質(zhì)處理，使硬度達(dá)到200~2