COMBINED CONTROL OF HYDROPNEUMATIC SPRINGS OF THE VEHICLE

Transcription

1 Journal of KONES Powertran and Transort, Vol. 18, No COMBINED CONTROL OF HYDROPNEUMATIC SPRINGS OF THE VEHICLE Mchal Lashenko Parhomenko Street 15-14, Volgograd, Russa tel.: (8442) , fax: (8442) e-mal: tslmv@vstu.ru Alex Podzorov Zholudeva Street 38-91, Volgograd, Russa tel.: (8442) , fax: (8442) e-mal: legonerav@gmal.com Vktor Shekhovtsov, Vyacheslav Prytkov Lenn Av. 28, Volgograd, Russa tel.: (8442) , 8 (905) , fax: (8442) e-mal: shehovtsov@vstu.ru, rytkov34@gmal.com Elena Cherkashna Lgovskaya Street 17, Volgograd, Russa tel.: (8442) , fax: (8442) e-mal: vlena400065@nbox.ru Abstract The artcle s devoted to research of a vehcle rde comfort, equed the susenson system wth combned control of srngng and damng elements. The satal mathematcal model of a vehcle whch meets the requrements of adequacy to real object was develoed. The results of the comuter smulaton of movement of the vehcle wth controllable and assve susenson systems on stochastc mcrorofle are resented. It can be concluded that the satal mult-mass model s satsfactory close to a real object and can be used for further calculatons. Havng analyzed smulaton results we can state sgnfcant ncrease of rde comfort of a vehcle equed wth a controlled susenson system. Decrease of vertcal acceleraton of a cabn n a lace where a drver sts amounted to 40% n average that can be consdered as a lmt value for ths tye of controlled susenson systems. It can be noted that a susenson system wth combned control of srngng and damng elements can be consdered as rather effectve n terms of decreasng load of vehcle srng-mounted arts that along wth low ower consumton makes t rather comettve. The shown research results and control laws for srngng and damng elements can be used as a bass for develoment of relatvely smle controlled susenson systems. Keywords: controlled susenson system, rde comfort, hydroneumatc srng, road tests, satal mathematcal model, vehcle

2 M. Lashenko, A. Podzorov, V. Shekhovtsov, V. Prytkov, E. Cherkashna 1. Introducton Passve susenson systems wth srngng and damng characterstcs remanng nvarable n the course of oeraton excet for the changes related to wear and tear, warmng u and breakdown are commonly used n exstng transortaton vehcles. Manly t s due to comaratvely smle and relable desgn, as well as to lack of necessty n external ower source. However erformance otentals of such systems n terms of meetng the demandng requrements for rde comfort are rather restrcted and have more or less reached ther lmt. Hence t s necessary to fnd new ways of ncreasng rde comfort of transortaton vehcles; one of them s to use varous knds of controllable susenson systems [7] whch allow changng srngng and damng characterstcs as er a secfed algorthm n the course of movng. Although these systems make the total rce for a transortaton vehcle hgher, as well as make the desgn more comlcated but allow mrovng rde comfort. Among the known knds of controllable susenson systems we can dstngush the semactve systems [8] whch are consdered to be the most otmal n terms of ncreasng rde comfort (advantage over assve susenson systems), ower consumton and desgn comlexty (advantage over actve susenson systems). The semactve susenson system s such a system where external energy s consumed only to change arameters of assve srngng and damng elements t ncludes, namely to change ther srngng and damng characterstcs. The artcle contans the research of the oeratonal effcency of the susenson system wth the combned control of srngng and damng elements (hydroneumatc srngs) when a vehcle moves on stochastc mcrorofle. 2. Algorthm of the combned control Analytcally, the used algorthm of control of damng element of hydroneumatc srng can be reresented through the followng equaton system: where: z, r r s r1, ( z r2, ( z r3, ( z ( z ( z ( z - vertcal velocty of srung and unsrung mass, ) 0) & ( ( z ) 0), ) 0) & ( ( z ) 0), ) 0) & ( ( z ) 0). s - current resstance factor of hydroneumatc srng, r 1, r2, r3 - factors of varable resstance of hydroneumatc srng ( r1 r2 r3 ), - hydroneumatc srng number. As control law for srngng element we suggest the algorthm the essence of whch s to change srngng and damng characterstcs of hydroneumatc srng by nterconnectng two volumes of gas cavty deendng on current values of vertcal seeds of srung and unsrung mass. The effcency was also nvestgated on a bus model wth controlled srngng elements of low ressure n the form of rubber-cord neumatc srngs [3-6]. Wth the hel of the equaton of srngng characterstcs of assve hydroneumatc element [2] we can get srngng characterstcs of hydroneumatc element wth the varable srngng and damng roertes whch wll be calculated as er the formula below: (1) F u z V o V F o j k Vo Vd F j V o Vd F z ( ) k F, (2) 230

3 where: F k F u o z V, j V d Combned Control of Hydroneumatc Srngs of the Vehcle - srngng force of hydroneumatc srng, - ntal excessve ressure n hydroneumatc srng, - olytrohc coeffcent, - hydroneumatc srng ston area, - rmary and addtonal volumes of gas cavty of hydroneumatc srng, - hydroneumatc srng deformaton concdng wth the moment of addtonal volume suly/cuttng off. Analytcally the algorthm of control of a neumatc srngng element due to change of ts oeratng volume can be reresented through the equaton system: V d, z ( z ) 0, V Vo F ( z ) V d, ( z ( z ) 0) &( z 0, ( z ( z ) 0) & ( z where: V - current volume of gas cavty of hydroneumatc srng. j j ), ). (3) 3. Satal mathematcal model of the vehcle The research of oeratonal effcency of the susenson system wth combned control of srngng and damng elements was erformed usng roven software (FRUND) [1]. Ths software system was used when constructng ZIL car, KAMAZ sort car, VAZ 2123 motor car etc; t s also used when desgnng and develong dfferent mechancal systems n the subdvsons of some Russan mechancal engneerng lants. Ths software system has allowed generatng a satal mult-mass model of a vehcle, general desgn dagram of whch s shown on Fg. 1. Fg. 1. General desgn dagram of a vehcle 231

4 M. Lashenko, A. Podzorov, V. Shekhovtsov, V. Prytkov, E. Cherkashna The vehcle s a 4x4 two-axle off-road conventonal vehcle wth ndeendent front and rear susensons. The model conssts of rgd bodes, namely frame 1, cabn 2, van 3, ower lant 4, wheels 5, lateral arms 6 and 7, stablzer bar 8, rods 9. The rgd bodes are connected to each other and to the road through the srngng and damng elements: hydroneumatc srngs 10, tres 11, as well as through dfferent knematc ars 12. The model of the susenson system fathfully reroduces front and rear susensons geometry of a real object wth varances and connectons of all degrees. In order to verfy the develoed model for valdty we comared the desgn data wth the exermental data acqured n the course of the road tests of vehcles wth a assve (noncontrolled) susenson system. The exermental data n the form of sectral densty and RMS of vertcal acceleraton of a cabn n a lace where a drver sts was acqured by measurng when movng drectly along a secal cobblestone road of the satsfactory qualty that correlates wth roads of category 2 (OST «Motor vehcles. Testng rocedures for rde comfort».) wth steady seed 55 km/h. The calculaton method was bult u smlarly to the exermental measurements method at road tests. Cobblestone road of satsfactory qualty was selected as drve functon. Fgure 2 shows the dagrams of desgn 1 and exermental 2 sectral denstes of vertcal acceleraton of a cabn n a lace where a drver sts when a vehcle wth a assve susenson system moves drectly on a cobblestone road of satsfactory qualty wth steady seed of 55 km/h. 1 desgn (RMS=1.27 m/s 2 ), 2 exermental (RMS=1.37 m/s 2 ) Fg. 2. Desgn and exermental sectral denstes of vertcal acceleraton of a cabn n a lace where a drver sts Table 1 shows desgn and exermental RMS of vertcal acceleraton of a cabn n a lace where a drver sts n 1/3 of octave frequency band. Comarson of the vertcal acceleraton sectral denstes curves, as well as RMS of vertcal acceleraton n 1/3 of octave frequency band derved through desgn and exermental ways shows accetable convergence n the frequency range of Hz for the vehcle movement mode under revew. Average devaton of the desgn acceleraton from the exermental one does not exceed 15%, whch s allowable for random nature of the rocess. Based on that, t can be concluded that the satal mult-mass model s satsfactory close to a real object and can be used for further calculatons. 232

5 Combned Control of Hydroneumatc Srngs of the Vehcle Tab. 1. Desgn and exermental RMS of vertcal acceleraton of a cabn n a lace where a drver sts, m/s 2 (1 desgn, 2 exerment) f, Hz , % f geometrc mean frequency, = (exerment - desgn / exerment) 100% Smulaton of movement of the vehcle wth controllable susenson system Then we smulated movement of a vehcle equed wth a susenson system wth combned control of hydroneumatc srng under smlar movement condtons. The smulaton results are shown on Fg. 3 and summarzed n Tab assve susenson system (RMS=1.27 m/s 2 ), 2 controlled susenson system (RMS=0.81 m/s 2 ) Fg. 3. Desgn sectral denstes of vertcal acceleraton of a cabn n a lace where a drver sts Tab. 2. Desgn RMS of vertcal acceleraton of a cabn n a lace where a drver sts, m/s2 (1 assve susenson system, 2 controlled susenson system) f, Hz , % = (assve - controlled / assve) 100%

6 M. Lashenko, A. Podzorov, V. Shekhovtsov, V. Prytkov, E. Cherkashna Havng analyzed smulaton results we can state sgnfcant ncrease of rde comfort of a vehcle equed wth a controlled susenson system. Decrease of vertcal acceleraton of a cabn n a lace where a drver sts amounted to 40% n average that can be consdered as a lmt value for ths tye of controlled susenson systems. 5. Conclusons To summarze, t can be noted that a susenson system wth combned control of srngng and damng elements can be consdered as rather effectve n terms of decreasng load of vehcle srng-mounted arts that along wth low ower consumton makes t rather comettve. The shown research results and control laws for srngng and damng elements can be used as a bass for develoment of relatvely smle controlled susenson systems. References [1] Gorobtsov, A. S., Kartsov, S. K., Kooshvd, R. P., Komlyeks FROoND nstroomyent sslyedovanya dnamk avtomoblya, Avtomobl'naya romshlyennost', No. 4, , Moskva [2] Pyevznyer, Ya. M., Goryelk, A. M., Pnyevmatchyeskye gdronyevmatchyeskye odvyesk, C. 316, Lyenngrad [3] Podzorov, Al. V., Gorobtsov, A. S., Lyashyenko, M. V., Prtkov, V. N., Isslyedovanye ooravlyayemoy sstyem odryessorvanya avtoboosa osryedstvom rostranstvyennoy matyematchyeskoy modyel, Izvyestya VolgGTOo, Vy. 3, No. 10, , Volgograd [4] Podzorov, Al. V., Gorobtsov, A. S., Lyashyenko, M. V., Matyematchyeskaya modyel' ooravlyayemoy sstyem odryessorvanya ATS, Avtomobl'naya romshlyennost', No. 9, , Moskva [5] Podzorov, Al. V., Gorobtsov, A. S., Lyashyenko, M. V., The otmal control of the multdmensonal system at stochastc exctaton, Journal of KONES, Powertran and Transort, Vol. 16, No. 1, , Warsaw [6] Podzorov, Al. V., Prtkov, V. N., Chyerkashna, Ye.A., Lyashyenko, M. V., The vehcle rde comfort ncrease at the exense of semactve susenson system, Journal of KONES, Powertran and Transort, Vol. 18, No. 1, , Warsaw [7] Savchyenko, A., Sovryemyennye aktvnye odvyesk lyegkovh avtomoblyey, Avtostroyenye za roobyezhom, No. 2, , Moskva [8] Fscher, D., Isermann, R. Mechatronc sem-actve and actve vehcle susensons, Control Engneerng Practce, Vol. 12, ,