【正文】 heads. * Cranes should never be used for side pulling. 華東交通大學畢業(yè)設計 31 * Hand signals between the operator and hooker should be clearly agreed upon and understood before moving a load. * The operator should never lift two separately rigged loads at the same time. * The operator should approach the desired position as far as possible at the main speed and use creeping for final positioning. Ropes,pulleys and drums Steel Wire Ropes Steel wire ropes are used as flexible appliances to lift loads and transmit motion and forces. Such ropes are wound from steel wire from mm to 2 mm in diameter and have an ultimate strength of 1400— 2021N/ wire ropes are available in a great variety of designs. Machines used in amterials handling,construction and road making are provided mostly with round double lay (cross or regular lay)ropes from 11mm to 32 mm in dismeter. Double lay ropes are manufactured from preliminarily twisted spiral wire a parallel (Lo。 Copyright Cahners Business Information, a division of Reed Elsevier, Inc. Apr 2021 Properly sized, designed, and installed bridge and gantry cranes dramatically increase production, significantly reduce material handling costs, and substantially lower the risk of employee injury. A properly maintained crane lasts at least 20 yr. could reach 50 yr or more, and occasionally outlives the structure or pany originally housing or using the equipment. These overhead workhorses maneuver large, bulky loads through the plant for shipping and receiving, relocating and staging, or integrating with heavyduty manufacturing operations. Computers and other control packages near the equipment or at a remote location allow the crane to closely match almost any size and type of load, where and when needed, and under all operational and environmental conditions. 華東交通大學畢業(yè)設計 29 Hoisting speeds over 200 fpm, bridge speeds to 1000 fpm, and capacities over 1000 tons are available, although slower movements and smaller loads are the norm. Cranes are 1530ft overhead, but could be up to 200 ft to clear floormounted equipment, to place material where needed in the manufacturing operation, or for safety reasons. A variety of mechanisms, such as hooks, mags, or buckets, are available on the hoist to match particular grabbing or lifting requirements. Types Bridge cranes are available in top running and underhung configurations, and single or double girder, to match plant structural and lifting requirements. Gantry cranes are constructed in single or double leg, single or double girder, and top running or underhung versions. Bridge cranes are usually used for high tonnages, long spans, and heavy duties. Although available in several forms, each crane design contains several pieces of mon equipment. * Hoists are used to lift and lower the load. * Trolleys consist of a frame, end trucks or wheels with side frames, and drive. They suspend or support the hoist, rope, and load block。 Once the wire rope snaps ， The automatic pellet of that unit is turned on buckleing at the primary vertical column and fiercely fastens on the staff ， Avert suspending the coop to drop 。 The wire rope on the hoister coil near the direction idle wheel on the hoister side loadbearing beam successively 、 Suspend coop peak ministry the assisting direction idle wheel 、 Master advances the idle wheel 、 Another side assisting direction idle wheel ， Admittedly afterwards being living stably on another loadbearing beam ， Constituteing suspends the coop to advance the system 。在此我還要感謝我的家庭對我的支持，使 我順利的完學業(yè)。 還要感謝同組的其 他 同學，大家相互幫助，共同努力，克服了一個又一個的困難，最終完成畢業(yè)設計。在我們遇到困難時，兩位指導老師會幫助我們克服困難，戰(zhàn)勝困難。感謝學校給我提供良好的設 計環(huán)境，讓我有一個安靜的設計教室，給我一個可以隨時查閱資料的圖書館，感謝其它給過我?guī)椭睦蠋熀屯瑢W。由于時間比較倉促， 優(yōu)化 效果并沒有達到最佳水準，但是通過設計還是了解了制作的全部過程，達到了設計的預期目的。 利用 MATLAB 軟件可以求解線性規(guī)劃、無約束規(guī)劃、二次規(guī)劃和有約束非線性規(guī)劃等優(yōu)化設計問題 .該軟件編程工作量小 ,初始參數(shù)輸入簡單 ,符合工程設計語言 ,有著很大的優(yōu)越性 .通過給出的優(yōu)化實例可以看出 ,應用該軟件求解機械優(yōu)化設計問題非常方便 。通過計算選用機構中所需的標準部件（如電動機、制動器、減速器、聯(lián)軸器、鋼絲繩等） ， 對非標準零件還須作進一步的強度與風度計算校核。 本次設計的任務主要是對起重機起升機構設計及對抓斗的 優(yōu)化 。,options) 姓名：董浩良 題目：抓斗結構設計與優(yōu)化 24 輸出最優(yōu)點和目標函數(shù)值： x(1)= x(2)= x(3)= x(4)= 與原設計方案 x=(,)下目標函數(shù) if 進行比較 ,在整個抓取過程中 ,優(yōu)化方案單位閉合繩拉力產(chǎn)生的抓取力比原方案提高 25%～ 31%。,x0,[],[],[],[],[],[],39。 [x,fval]=fmincon(39。off39。largescale39。 x0=[,]。 %優(yōu)化約束 ； function [c,ceq]=confun(x)； c=[ x(1)^2(x(2)sin(x(4))x(3))^2(x(2)cos(x(4))+)^2/x(2)sin(x(4))x(3)/(x(1)+x(2))cos(x(4))x(3)/(2)/(3)/(4)/(x(2)*sin(x(4))x(3))^2+9x(4)cos(x(4))+)^2x(1)^2/x(1)+x(3)x(2)/x(4)]。 首先用 MATLAB 編寫目標函數(shù)的 m文件 ，返回 x 處的函數(shù)值 f。 ? ? 02318 ???? xxxxg （ 411） ? ? 049 ??? kxxg ? （ 412） ? ? jj xxg ??9 (j=1,2,3,) （ 413） 其中 , 1C 和 4C 控制閉合滑輪組上、下滑輪軸閉合狀態(tài)下 最小及最大距離 , 2C 控制抓斗機構最大寬度 , 3C 與閉合滑輪組滑輪大小有關 ,ρ 為散料動態(tài)堆積角。 ? ? ? ? ? ? 0c o s 34213 ????? xxxxxg k? (d)保證抓斗結構緊湊 。 ? ? ? ? ? ? 0s i n 21422342213 ?????? Cc oxxxxxxxg （ 45） （ b） 避免閉合狀態(tài)下?lián)螚U力臂過小。 1C =, 2C =, 3C =, 4C =, k? =π /5。由于 C 為常數(shù) ,令 isii CSFf2? （ 43） 則 ,長撐桿抓斗機構的優(yōu)化 函數(shù) 為 ? ?TnfffV ....... .,m a x 21? 等價與 ? ? ? ? ? ?? ?? ? ??????????????????2221222 s i ns i nc o ss i nallalLlCSFiiiiisi???????? （ 44） 設計變量 決定優(yōu)化目標 if 的 獨 立 變 量 只 有 Ll1 , Ll2 , La 及 a , 并令Llx 11? , Llx 22 ? , Lax ?3 , ??4x ,它們構成了抓斗機構優(yōu)化設計的設計變量。在抓斗閉合末期 ,增大 isi SF 2 可以獲得較大的水平閉合力 ,有利于將抓到的散料壓入顎板中 ,提高抓斗在閉合后期的填充能力。或者可以采用較寬的抓斗。在抓斗閉合初期 ,增大 isi SF 2 有利于減緩閉合繩拉力的增加 ,可以在較小的閉合繩拉力時有較大的抓取力 ,增加抓斗的下沉力。長度均以 m 為單位 ,角度以弧度為單位。 圖 12為抓斗機構簡圖。若合理匹配機構幾何尺寸 ,使相同開度下單位閉合繩拉力產(chǎn)生的抓取力提高 ,將有利于減輕抓斗自重 ,提高抓取比。 華東交通大學畢業(yè)設計 21 4 抓斗優(yōu)化 優(yōu)化目標 抓斗抓取散料需要能量 ,長撐桿抓斗的這個能量主要通過閉合繩拉力及抓斗重心的垂直運動引起的重力勢能的改變獲得