Improve intelligence electro-hydraulic the dependability research of scale control amplifier

Theory By Total Distributed Control Systems of 　 of On The Basis Of Discussing The Reliability, of Series Hardware Circuit of 　 of It Puts Forward The Reliability Design.

Keywords:ITechnology of dependability of overview of Electrohydraulic Proportional Control1 of Ntelligent Controller 　 is the new task that recent science and technology offers. Before dependability becomes the quality target with Electromechanical new facility, conventional science and technology can satisfy mechanical and electrical products basically to work reliably, because dependability has not been become,be one of science and technology highlights a problem at that time only, have not give enough attention to its. Apply at industry to dominate a field widely increasingly as microprocessor, the dependability that controls a system to personal computer raised taller requirement [1] . The functional design of system of personal computer control is to build what go up in dependability design foundation, if do not have dependability design to perhaps do not handle this work seriously, so the function is again much again strong control system also can be necessarily in application come a howler. The specific requirement with more harsh environment of our country industry also asks that he must put dependability design in the first place. Seventies metaphase, what be core with microprocessor is distributing center model TDCS(Total Distributed Control System) of integrated control system is born in succession in the United States and Japan [2] . Because TDCS is ultimate goal with high reliability, because this is in,be born before long establish its control medium mainstream position in the process. The theory to controlling a project and practice have the dependability technology that analyses TDCS deep great sense. The article is in namely brief discuss academic base of TDCS dependability technology to go up, research analysis intelligence is electro-hydraulic the dependability design that scale control amplifier adopts. By sheet piece the amplifier of intelligent scale control that aircrew becomes is one kind uses comparative exemple electro-magnet to provide specific function electricity, right electro-hydraulic the electronic unit that proportioning valve or system have open loop or closed circuit adjust. It is electro-hydraulic the important composition of scale control component and system is unit. Electro-hydraulic the transmission that scale technology uses extensively at all sorts of diverse demands and control system, the flexibility of amplifier and dependability are having crucial effect. When the academic method that dependability of 2 　 TDCS analyses analyses TDCS dependability, want to consider breakdown λ and its shape of a distribution not only, consider subsystem structure, and should consider a system but maintainability, consider maintainability μ to reach its to distributing. Dependability theory points out [1] [2] [3] : (The probability obedience Poisson that 1)TDCS breakdown produces distributings. Set the average breakdown number that produces inside unit time to be λ , the probability that produces K second breakdown inside T time is (1) 　 and, if breakdown produces probability,obedient average distributings for the Poisson of λ , criterion the index that it produces removed distributinging obedience average to be 1/ λ distributings, namely Exp(- λ T) 　 . Barrier of 1/ λ hereat produces the average of time-interval, write down M, call MTBF of mean time between failure. (The probability that formulary function fulfils continuously inside the time that 2) system falls in working requirement of the regulation and books is systematic reliability, write down R(t) . Function of the so-called provision that finish is to point to do not malfunction, because of this type (when the K=0 in 1) , by reliability the definition has: R(t)=P(0, t) ＝ E - λ T (2) 　 type (the basic formula that 2) is TDCS reliability namely, what ought to explain is TDCS it is a complex system that makes by a lot of subsystem, it is system of control of computer of industry of a storied, its reliability is each subsystem essentially reliable integrated. (After malfunctioning, 3) resembles such TDCS computer to control a system is OK of repair. Be measured to the rehabilitate of breakdown normally with repair time, be in theoretic with but maintainability, the definition ends to be repaired in the system inside proper time the probability that return to normal. The index of repair time obedience of TDCS distributings, its average is set for H, time T is passed after the system malfunctions still not the probability of repair is equal to Exp(- T/h) , and inside T time the probability of repair is: M(t)=1-e - T/h(3) 　 call H MTTR of mean time to repair, 1/h of ＝ of its reciprocal μ calls maintenance rate, namely number of breakdown of the rehabilitate in unit time. The reliability of TDCS and but the main index that maintainability perhaps says corresponding MTBF or MTTR is descriptive TDCS dependability. (4)TDCS is using the no more than in the process is two kinds of condition, one kind is systematic work, one kind is the system halts use. Former state the system is regular, latter states whole system provides a function because of malfunction and cannot be being finished. Apparent, systematic utilization rate is normal run time and summation time than. The utilization rate of this kind of TDCS calls systematic availability or broad sense reliability. To having the TDCS that stabilizes condition, availability and time coordinate have nothing to do, availability does not follow time T and change namely, call stable state availability or stable availability, write down the ∞ that it is A() or A. Reach not hard (4) 　 type (the most important formula that 4) is analytic TDCS dependability. As a result of the complexity of breakdown, repair time is very complex also, of TDCS normal the changeover with state of fault is more complex also, it is a random process. The reliability of TDCS and maintenance rate comply with index distributings, consequently it can use Maerkefu (Marker) process will describe. Although the breakdown of TDCS or normal the occurrence of two kinds of condition is random, but the condition that appears after the system is concerned with present condition only and have nothing to do with the condition previously. This kind only with voice is concerned and call with the process that voice has nothing to do first now without aftereffect sex, be defined to be process of Ma Erke's husband. In process of Ma Erke's husband, the system changes another kind of condition to be able to change probability method to consider with condition by a kind of condition. Set whack of system of a TDCS to be S, write down for condition 1: State of fault is F, write down for condition 2. Criterion the system turns by S with the probability of λ for F, maintain whack with the probability of 1- λ . The system of state of fault turns by F with the repair rate of μ for S, still be in F condition with the probability of 1- μ . Afore-mentioned condition change usable matrix to express: (5) 　 is in real problem, the condition number of TDCS can be N, criterion the common form of matrix of its state move is (the probability that condition I move comes condition J for the Pij in type of 6) 　 . By dependability theory the state move matrix of knowable TDCS has a very main character [1] : As the progressively move of condition, the system is located condition probability tends gradually stable. After setting systematic condition to stabilize, the probability of each condition uses vector [P1, p2, p3, ... , pn] express, have (7) 　 analyses afore-mentioned assuming with it when the circumstance, have (in 8) type, PS is in the probability of whack for the system; PF is in the probability of state of fault for the system. It is because of the sum of vector of systematic condition probability again 1, have (9) by type (7) and type (9) can be solved TDCS 　 N the probability P1 of condition, p2, ... , pn. By type (8) and type (it is normal that 9) can be solved so that assume case issues TDCS the probability with breakdown. (Type of 10) (11) 　 (10) and type (4) is consistent, mirrorred usually the availability of TDCS. The TDCS of integrated consideration any of technology of dependability of 3 　 TDCS is analysed from total construction, the becomes 100 kinds of TDCS structure that appears now without giving thought to how the ground differ in thousands ways, they always are cent is 3 much, communication network and process interface, man-machine interface, among them each part included a lot of unit, each unit device is comprised by a lot of component again. Accordingly, from go up at all tell, the reliability of TDCS depends on of the reliability of component, component string, the network structure that paralell connection or the combination that configure redundantly and each unit make. Contemporary TDCS requirement has integrated consideration to dependability technology [2] . The dependability technology of TDCS only then at design phase, nowhere takes no account of the component of whole system and construction of system dependability. Besides dependability design, still put forward dependability to check standard and regulations, level reliability is debugged in installation the test is perforative from beginning to end, still consider to use medium safety, reliable issue finally. TDCS dependability technology can generalize for 3 respects [1] : (1) makes the system malfunctions not easily as far as possible (tall MTBF) ; (2) makes systematic breakdown eliminates quickly as far as possible (low MTTR) ; (Although 3) malfunctions, the system moves not to suffer breakdown effect. was called normally at 3 o'clock fault tolerance function. What article key considers is on one hand, make the system malfunctions not easily as far as possible namely. By type (4) is knowable, be about to increase systematic availability, one of basic approaches are the MTBF that improves a system, and of systematic MTBF rise to rely on those who form the MTBF of unit device and its component to rise again. For this, controller any yuan the use of parts of an apparatus answer manual of comply with user, yuan the use voltage of parts of an apparatus should not exceed its rating, three what electric current and power comsumption are less than rating, do not want as far as possible rated move, otherwise easy ageing. Use cell of low power comsumption as far as possible. To disturbing the HTL parts of an apparatus with greater threshold value and MOS parts of an apparatus, mutual join should match between different and phyletic parts of an apparatus. Relation of sequential of controller parts of an apparatus should have enough surplus, worsen when moving environment otherwise or run ageing for a long time, can cause systematic sequential to the relation does not match and be out of order. Have some of power driver element, be like high-power transistor, the ascendant follow that its command signal and drop along must very steep, otherwise component of switch of this kind of power will be burned-out. Because the dissipation power of power switch is equal to switch pressing to fall,this is with electric current indigestion. Guide when switch saturation when connecting, fall as a result of switch pressing dinky, switch dissipation power is very so little. When switch ends, because had shed the voltaic minimum of switch, accordingly, switch dissipation power is very little also. The signal edge that if control power switch to connect,breaks is not steep, so, power switch is in charge of cannot quite rapid saturation or end, namely power switch canal works in enlarge area condition time is longer, be in thereby approach the time that fall and high-power produces below big electric current greatly longer, can make result put a canal to burn out quickly. To computer control system, the ability of bus line drive of CPU is finite, want to take a moment of a lot of core when CPU bus line accordingly, ought to pass drive of bus line driver, can make systematic work unusual otherwise. Power source device also belongs to yuan of parts of an apparatus kind, carry out a proof, the stand or fall of power source quality has quite big immediate effect to systematic dependability. Power source wants communication to purify ability strong, it is good that the output when laden change makes the same score stability. Generally speaking, systematic power source should be comprised by communication transformer. Capacity of systematic power source should have enough surplus. In addition, systematic input matters to systematic output necessarily, input mistake causes output error necessarily. Above all, sensor itself dependability is close friends, the choice of sensor wants appropriate, should not exceed 2/3 of sensor normal operating conditions in the job. Measure sensor to imitate, its output has polarity, when the system need not consider signal polarity, the input magnifies circuit should design circuit of absolute value enlarge, do not affect systematic output when transmission line is received instead because of reason so. Input signal should undertake filter wave is handled, input interface circuit designs input protection even, prevent to input signal too big and attaint interface. To getting the circumstance of interference easily, some inputs signal ought to use encode modulation signal. Be inputted redundantly to inputting signal importantly to be able to be used and increase to be received secondhand, choose that input value inside normal limits. The content that design of systematic output dependability includes is more, include to output transmission line of interface circuit, output and output to carry out normally implement feasibility design. To computer control system, still include to output the dependability design that controls software. Although 4 last words used advanced dependability to design a technology, actual in the hardware that should make without reason block is impossible. In the system that spends dependability in requirement freeboard, hardware must be turned redundantly, because this still must be used double change and mothball technology (namely redundant technology) . As the progress of modern science and technology and development, electro-hydraulic scale technology more and more apply at each industry domain widely, this controls amplifier to have higher reliability and flexibility with respect to requirement scale, improve ceaselessly only with perfect, ability offers first-rate to control signal for scale component and system. CNC Milling