| The concrete delivery pump has been one of the most widely used constructionmachinery. In recent years our country economy rapid development, theinfrastructure step sped up, which enables the concrete delivery pump technology toobtain the considerable development in our country. It can once finish horizontal andvertical transportation in succession, with high efficiency, low workforce andexpense. Especially in the construction sites that other transporters are difficult toclose, concrete delivery pump can work effectively. Today the combination of themixed concrete production and pump sending changes the appearance ofconstruction site. The skill of pump pouring promises the high efficiency and goodquality of the construction, which is more and more favored in construction field.Recently with the rapid progress of economic, the technique of concrete deliverypump has been developed remarkably.At present the domestically produced concrete delivery pump still by thehydro-valve control primarily, this control mode not only the hydraulic structurecomplex, the control was not convenient, moreover constructor's labor intensity wasvery big, but electro-hydraulic proportional control then might overcome the aboveshortcoming. This article already applies the electro-hydraulic proportional controltechnology to the closed type concrete delivery pump control, which has realized theclosed type concrete delivery pump constant power control, and effectivelyeliminated the pressure impact.On the base of analyzing the concrete delivery pump hydraulic system, thehydraulic system mathematics modeling has been established:1. Transfer function modelings)(2ms2Bs2k)4c(1vAscs)F(s)4c(1vA(s)cAknX(s)p2eto2tLeto2tpdppp++++Φ?+=ββMay infer two systems transfer function according to the above mathematicalmodel:(1) Input transfer function:p v2ph2h hG(s) = ΦX ((ss)) =s( ωs + k2ωξs + 1)(2) Disturbance transfer function:t2p 1N 2Lh2h hG (s) = XF ((ss)) = s( ?ωs Ac + (21ωξ +ωss +) 1)Through to the system transfer function analysis, qualitative had understoodsystem each parameter to the system performance influence, optimized the design toprovide the theory basis. Velocity magnification factor kv affects directly the systemstatic error. But in kv the only variable is np, therefore rotational speed np of the oilpump should be enhanced as far as possible under the permission condition toincrease the kv value. Hydraulic natural frequency ωh tokens the cylinder speed ofresponse. Through suitably selects Vo and βe to enhance ωh value, to improve thespeed of response. Liquid damping factor ξh tokens the overall performance of thepump-control-cylinder system. Through suitably selects Vo and βe to enhanceωhvalue, to guaranteeξh between 0.1~0.2.Through to the computer simulation of system transfer function may know: Theeach dynamic target of system can answer the purpose well under the unit step leapand the unit pulse input, which explained this system may realize the stepless speedchange function in the pumping process;The system can very quickly restorestabilization when the perturbation (outside load) changes , which explained theanti-perturbation ability of the system is very strong, and explained the system caneffectively eliminate the pressure impact.2. State equation modelingQVA)RP(QQCP 1c1azlpayprayay = ????(PAFFPA)IIV 1ayzfaffyaa = +???(VAQQVA)CP 1ayc1c2cyff = +??(PAF)IV 1fyfccc = ?Through to the computer simulation of system transfer function may know: Thesystem pressure impact does not occur in the time of oil pump fast commutation, butoccurs in the advancement time after the compaction concrete. Through the computersimulated the "SN" function, saw the "SN" function may effectively eliminate thepressure impact.Through the test of electrically controlled closed type concrete pump, theConsistent between tested pressure curve and smulation curve has proven themodelling accuracy. Might see the system has the constant power function.throughthe current-pressure curve.The research work of this paper enhances the technical level of the domesticallyproduced concrete delivery pump and has project application value.
|
PDF Full Text Request