数控机床毕业设计外文翻译---对电控带式铣床运用液压自动精度控制和宽度控制-数控设计(编辑修改稿)

数控机床毕业设计外文翻译---对电控带式铣床运用液压自动精度控制和宽度控制-数控设计(编辑修改稿)内容摘要：

REC function is described later in more detail ) . The functions of the coordinating and logging microprocessor are evident。 it organizes the data flow between the various processors on the Ether and analyzes , stores and points out engineering and production data .  Control system operational features AWC system The AWC system has two functions。  Reduce end crop losses by minimizing underwidth ends .  Improve width tolerances in the body of the bar . Since the edger concerned is E4 and the bar is paratively thin ( approximately 50 mm ) , little can be done to improve necking already created by the previous roughing /edging stands .Nevertheless , a small improvement can be expected by avoiding further worsening through stand E4/R4 . This is acplished by preopening the edger roll gap a calculated amount and then swiftly closing onto the target width as the head end enters the edger . A similar procedure occurs at the tail end , when the gap is quickly opened a calculated amount . The loci of these fast cylinder movements (eg , linear , expontial , parabolic , etc ) can be chosen by the setup puter , as well as the required gap adjustment velocity and stroke length . Accurate tracking of the approach of the head and tail end is essential . This is achieved by special hot metal detectors coupled with bar speed measurement . Inbar width control has two modes : BISRA gagemeter , and feedforward . Although the potential for the former mode of control ( which relies on the accurate sensing of instantaneous roll force to reduce mill stretch ) was always considered limited , due to the high frictional forces relative to the low rolling loads , it was , nevertheless , investigated . It 大学毕业设计 — 外文翻译 6 was found to be unsatisfactory for the reason stated . The feedforward mode , utilizing ining width error variations detected by a widthmeter after stand E3/R3 , was successful . It resulted in exit width variations , measured after stand E4/R4 , within + mm for 95% of the bar length , as measured by the new widthmeter in this location . This instrument is used to give bar to bar width updating to maintain system calibration . However , it is not used for in bar monitor feedback , because the transport distances involved are a significant proportion of the bar length .  Hydraulic AGCThe operational features included in the hydraulic AGC system can be divided into those that can be considered as conventional and those that have a novel element . Conventional AGC features include : absolute and lockon BISRA gagementer modes for each hydraulic stand。 variable mill modulus。 oil film pensation。 draft ensation and absolute or lockon feedback monitor . Absolute and lockon BISRA gagemeter modes for each hydraulic stand are selectable either automatcally by the SCC or manually . The BISRA gagemeter action artificially stiffens the mill modulus . This occurs because the feedback from the measured roll foece causes the AGC cylinders to extend to pensate for mill stretch . The amount of pensation can be varied from zero ( ie , no gagemeter action ) , which leaves the mill with its natural mechanical stiffness , to 100% which , in effect , increases the mill modulus to infinity . Each hydraulic stand can be given a stiffness value ( 0 to 100% ) either from the SCC or manually . Dynamic oil film pensation is obtained by cylinder movement to correct for dynamic changes in the backup roll bearing oilfilm thickness , which varies as a function of speed and roll load . Every gage correcting movement of the AGC cylinders results in a strip massflow change that alters the looper angle which , in turn , requests the stand speed to change . This sequence is anticipated and effectively shot circuited by direct speed trim signals sent directly from the AGC . With regard to absolute or lockon feedback monitor ,stand F7 etit xray gage can be selected to back in either mode . In the former mode , the system continues to make 大学毕业设计 — 外文翻译 7 corrections until the target gage is achieved . In the latter mode , the headend gage is accepted and maintained consistently for the remainder of the coil . Novel AGC features include : autosteering。 distibuted monitor feedback。 and roll eccentricity pensation . Autosteering , in which the tendency for the strip to steer to one side as a consequence of uneven heating across its width , is opposed by the control system . The roll force difference side to side is measured and fed to a functional representation of the tilt modulus of the mill stand ( the measured mill modulus characteristic when the roll gap is tilted differentially ) . The output of this functional block represents the amount of roll stack tilt that must ha。