Advancs in auomaion dsign for fas vssls propulsion M. Alosol, G. Bnvnuo & M. Marlli Dparmn of Naval Archicur and Elcrical Enginring, Gnova, Ialy M. Galli Sasma S.p.A., Gnova, Ialy ABSTRACT: Suprior prformanc, flxibiliy and nrgy fficincy, mak mor and mor imporan h auomaion rol in marin propulsion applicaions. Conrollr hardwar and sofwar should b dsignd for saf opraion in all condiions, as wll as for high dynamic prformanc. Th incrasing complxiy of h acual marin propulsion sysms lads o h dvlopmn of ddicad conrol funcions, according o spcial rquirmns. In ordr o s prformanc and rliabiliy of h propulsion conrol logics, nw dsign approachs for h marin auomaion dsign should b inroducd. Wih rgard o his, h Ral Tim Hardwar in h Loop (RT HIL) simulaion chniqu is bcoming a sandard par of h dsign procss for h propulsion conrollr of h las and mos imporan Ialian naval vssls. This papr dals wih som nw soluions in auomaion dsign, from h RT HIL simulaion bnfis o h inroducion of spcial conrol aspcs, du o h nd o manag high powr ngins for diffrn propulsion condiions. In paricular, h gnral propulsion auomaion schms, analysd in his papr and proposd for high powrd fas ships, ar h rsuls of h xprinc gaind by h auhors during h coopraion bwn Gnoa Univrsiy and h Ialian auomaion providr Sasma S.p.A, for h propulsion conrollrs dsigns of h aircraf carrir Cavour (COGAG propulsion) and FREMM Class frigas (CODLAG propulsion). 1 INTRODUCTION Th incrasing dmand for a fas and conomical marin ranspor of passngrs and frighs is giving rnwd boos o svral innovaions and dvlopmns which will s h nw sandards for h nx marin propulsion applicaions. Th nw propulsion sysms ar dsignd o m h nds of boh commrcial ships and high powrd naval vssls, in ordr o saisfy h growing dmand for highr spds. In paricular, in rcn yars, mor and mor powrful marin gas urbins, ofn combind wih h wll known advanags of lcrical propulsion (CODLAG or CODLOG sysms), hav bn fully xploid by many of h world s navis. Nw arg powr lvls hav bn plannd o magniuds which wr unhinkabl up o a fw yars ago. Th incrasing complxiy of hs nw marin propulsion sysms lads ncssarily o h dvlopmn of ddicad conrol funcions, abl o manag such high powr lvls in a saf way and for diffrn propulsion condiions of h vssl. In ordr o s prformanc and rliabiliy of h propulsion conrol logics, nw dsign approachs for h auomaion dvlopmn hav bn rcnly inroducd: for insanc, h Ral Tim Hardwar in h Loop (RT HIL) simulaion chniqu is bcoming a sandard par of h dsign procss for h propulsion conrollr of h nw Ialian naval vssls. According o his dsign approach, h propulsion sysm is simulad by a numrical cod which is linkd in ral im o h ral hardwar (h CPU ha conrols h ship propulsion sysm), providing o h dsignr a ralisic fdback bfor h insallaion on board of h ral conrol sysm. Rgarding ohr advancs in auomaion dsign for fas vssls, a brif ovrviw of h mos inrsing conrol funcions for rcn COGAG and CODLAG applicaions will b prsnd in his papr. Th gnral schms of propulsion auomaion, shown hrinafr, ar h rsuls of h xprinc gaind by h auhors during h las wo coopraions bwn Gnoa Univrsiy and Sasma S.p.A. for IX HSMV Napls 25-27 May 2011 1
h dsign of h propulsion conrol sysms of h aircraf carrir Cavour and FREMM Class frigas. 2 SIMULATION BASED DESIGN 2.1 Prooyping sysm. During h simulaion basd prliminary dsign, i is propr ha simulaion runs in bach mod, in ordr o achiv all h calculad daa in h fasr im (ha mans a s of 60 sconds, for xampl, is simulad by PC in lss han 60 sconds). Th calculaion im dpnds on svral facors rgarding boh som hardwar soluions (compur mmory, CPU spd) and h dvlopd numrical modl (simulaion im sp, siffnss, kind of solvr for h ordinary diffrnial quaions). In his phas, h conrol logic can b dsignd and h svral gains of h rgulaion loops can b s in an idal sysm, rprsning h inracion bwn wo sofwar-only simulaion modls (conrol sysm and ship), as i is illusrad in Fig.1. CONTROL LOGIC Commands, Spoins.. Fdbacks SHIP MODEL (ngin, shaf lin, propllr, c.) Figur 1. Daa xchang bwn conrol and ship simulaor 2.2 Conrol sysm onboard. A ypical archicur of h propulsion conrol sysm of a ship could b h following: FIELD (ngin, shaf lin, propllr, c.) IO BOARDS IO BOARDS IO BOARDS Rdoundan CPU 1 Rdoundan CPU 2 Rdoundan CPU 3 Figur 2. Archicur of h propulsion conrollr Svral CPUs ar usually usd o conrol diffrn componns of h propulsion sysm, rying o limi h los of funcionaliis in cas of failur of on of hm (vn if ach CPU is usd in a rdundan configuraion). E h r n L A N Unforunaly, h bhaviour of h ral hardwar on board could b qui diffrn from ha on simulad during h prliminary dsign phas. Th main diffrncs could b du o h cyclic im of h CPUs, h diffrn im dlay in xchanging daa among conrollrs and h naiv funcions ha can b implmnd; furhr diffrncs could b rprsnd by h prsnc of many funcionaliis usually no implmnd in h ship numrical modl (bu ha inrac wih h propulsion conrol) and h housands of signals ha h auomaion has o monior on h ral sysm. In h ral sysm, h whol conrol sysm has o work in ral im and h auomaion dsignr has o b sur ha h prformanc forsn by simulaion will also b mainaind in a ral nvironmn. To his nd, i is ncssary o limi, as soon as possibl, mos of h diffrncs bwn h wo worlds. This could b mad possibl by h adopion of h RT HIL mhod. 2.3 RT HIL mhod. Onc h conrol logic prformanc has bn valuad by using bach simulaion, h conrol subsysm is sd by RT HIL simulaion. This dsign chniqu consiss in s sup whr h ral hardwar conrollr can xchang daa wih h ship propulsion modls (ngin, shaf lin, propllr, ship moions, c.) ha ar simulad in ral-im (for xampl, a s of 60 sconds mus ak xacly 60 sconds o run on PC). Gnrally h s of h ral conrollr is mad on shipboard, parially during h dlivry priod and complly during ship full scal rials. Ths rials ar im consuming and vry xpnsiv, as hy rquir h full ship availabiliy. By using RT HIL simulaion, h physical availabiliy of h ship is no rquird, hus h conrollr sing can b don vn bfor h ship is buil. In ordr o incras h simulaion ralism, som funcionaliis, no implmnd in h ship modl, ar simulad by cods insid h conrollrs. Dinav Frmm.x Ral Tim Applicaion CLIENT SERVER 1 SERVER 2 SERVER 3 Logics Logics Logics Figur 3.Ts-bd usd for RT HIL rials CPU 1 CPU 2 CPU 3 Simulad Funcionaliis Simulad Funcionaliis Simulad Funcionaliis E h r n L A N IX HSMV Napls 25-27 May 2011 2
Fig. 3 shows h block diagram of h xprimnal sup usd for sing h conrollr of h FREMM Class frigas. In paricular, h fil namd Frmm.x is h RT applicaion ha xcus h propulsion modl. I is an clin ha rads h command paramrs on h conrollrs, hrough srvrs, and wris back h rsuls. srvrs and h Frmm.x applicaion rsid on h sam PC and ach Srvr xchangs daa wih on conrollr hrough Ehrn LAN. Th Simulad Funcionaliis can inrac wih an HMI (Human-Machin Inrfac) pag in ordr o supply commands from usrs (i.. h slcion of h lvr posiion and of a prcis propulsion mod) and o simula h minor sysms no implmnd insid h modl. All of h paramrs xchangd via can b loggd o a fil bu hy ar also availabl o h auomaion dsignr by mans of a graphical panl, as illusrad in Fig. 4 and Fig. 5. In his way i is possibl o hav a comprhnsiv viw of all h sysm working paramrs. advanag of h RT HIL approach: no only h dsignr can dbug h conrollr bfor h on board dlivry, bu i is also abl o s i in bordrlin siuaions, ha can b difficul o obain wih h ral ship. 3 CONTROL FUNCTIONS 3.1 COGAG applicaion. A modrn conrollr layou for a COGAG applicaion, in according o a gnric propulsion sysm as shown in Fig. 6, could b rprsnd by h schm of Fig. 7, whr h conrol logics of a singl shaf is illusrad. Figur 6. COGAG propulsion sysm Figur 4. Snapsho of simulaion inpu panl Figur 5. Snapsho of simulaion oupu panl Sinc h Frmm.x applicaion is complly configurabl, i is possibl o ry h conrollr wih diffrn working scnarios (i.. diffrn ambin mpraur, ruddr angl, c.). This is an addiional IX HSMV Napls 25-27 May 2011 In h proposd schm, h bridg lvr posiion signal is convrd ino a rfrnc valu for h propllr pich and spd by mans of wo combinaor abls, whr h sady sa valus for propllr pich and spd, dpnding on lvr posiion, ar rspcivly rpord. Th pich spoin is possibly corrcd o kp ach ngin wihin is orqu limi during vry condiion, whil h rqusd propllr spd is compard wih h masurd acual shaf spd o fd a PID algorihm, abl o assss h GT hrol dmand. This kind of spd rror is adjusd on h basis of h acual GT orqu, in ordr o ak ino accoun h possibl diffrn prformanc of h wo ngins acing on h sam shaf. In raliy, h final GT hrol is h minimum signal bwn h rsuls achivd by wo PID algorihms, which ac : 1) On h shaf spd rror; 2) On h diffrnc bwn h orqu limi (for insanc qual o 85% of h GT nominal orqu) and h GT acual orqu. Th GT hrol signal is calculad on h basis of h orqu rror o prvn ovrloads, bu as h possibl corrcion of h pich spoin is mad on h basis of a orqu limi which is lowr han h prvious on (i.. 75% of h GT nominal orqu), h possibl ovrload procion is drmind firsly by h pich rducion and hn by h GT hrol rducion. 3
Figur 7. Conrollr layou for COGAG applicaions Onc h GT hrol dmand is calculad, h corrsponding Turbin Conrol Sysm (TCS) has o rgula h ful flow in ordr o achiv h propr powr rquird by h propllr (Alosol al. 2010a). Th propulsion conrollr is dvlopd in ordr o prvn h inrvnion of h innr govrnor of h ngins. In fac, in his conrol logic, h procion funcions of h ngins local govrnors hav o ac only as h las ool o avoid ovrorqu, ovrspd or ovrmpraur of h propulsiv machinry during ransin or mrgncy condiions. A h nd, h main funcions of h considrd conrollr can b so rsumd: - calculaion of propllr spd and pich spoins, by using auo-adapabl ramps basd on ship spd (blocks 1 and 2 in Fig. 7); - ngin hrol calculaion, mainly on h basis of h shaf spd conrol; - ovrload procion, by acing on h propllr pich, in ordr o avoid ngin orqu paks; - orqu balancing of h wo gas urbins acing on h sam shaf. ddicad funcions o safly manag h various propulsiv mods of h vssl. Figur 8. Exampl of CODLAG propulsion sysm Also in his cas, h conrol dsign cririon is o prvn h inrvnion of h Turbin Conrol Sysm (TCS) and h innr govrnor of h lcric moor. In h GT mod, h conrollr layou similar o ha of a CODAG sysm (s Fig. 9). 3.2 CODLAG applicaion Th complxiy of his rcn and innovaiv CODLAG sysm (whos possibl configuraion is shown in Fig. 8) rquirs h dvlopmn of a propulsion conrollr abl o prform svral and Figur 9. Exampl of CODAG propulsion sysm IX HSMV Napls 25-27 May 2011 4
Figur 10. Conrollr layou for CODAG/CODLAG applicaions Th conrol schm, proposd for boh cass in h GT mod, is illusrad in Fig. 10. Th bridg lvr posiion signal, modulad by auoadapiv ramps basd on h ship spd dmand (blocks 1 and 2), is convrd ino a propllr blad posiion and shaf spd rfrnc valu by mans of h combinaor abls. Th rqusd propllr spd is hn compard wih h masurd shaf spd and h corrsponding rror fds compnsaing algorihms (PID block) in ordr o calcula h hrol dmand of h gas urbin or h lcric moor, rspcivly for h GT mod and EPM mod. Morovr a spcific conrol loop, acing firsly on h propllr pich and scondly, if ncssary, on h GT ful flow, is addd o his kind of rgulaion in ordr o mainain h gas urbin or h lcric moors wihin hir orqu limis during vry opraional condiion. In paricular, h final GT signal, which fds h TCS, is calculad as h minimum signal among hr signals achivd by h following acions: - shaf spd rgulaion (signal calculad by a PID algorihm, on h basis of h shaf spd rror); - GT orqu procion (signal calculad by a PID algorihm, on h basis of h rror bwn h GT orqu limi and h GT acual orqu); - shaf orqu procion (signal calculad by a PID algorihm, on h basis of h rror bwn h shaf orqu limi and h shaf acual orqu). Th normal rgulaion basd on h shaf spd is usually adopd by many marin conrol sysms bu h mos dlica poin, ha maks diffrn his propulsion conrol sysm from h ohr radiional conrollrs, rgards h paricular yp of h usd garbox, characrisd by wo oupu shafs. In fac, for his rason, h normal rgulaion of h ngins, basd on h shaf spd, is no propr for h CODLAG mod, i.. whn h ovrall conrollr has o calcula h signals o snd o boh h GT and h wo EPMs, bcaus in his propulsiv configuraion i would b improbabl o achiv simulanously for h wo shafs h sam xac fdback, rgarding h propllr spd, during ransin condiions. Thrfor, in CODLAG mod, h EPM rgulaion is only basd on a powr rfrnc ha aks ovr whn h GT hrol dmand xcds for xampl h 85 % (Alosol al. 2010b). Morovr, h paricular rducion gar arrangmn can suggs o inroduc ino h conrol logics a furhr capabiliy, in ordr o prsrv h h of h gars from orqu unbalancs during criical urning circls of h vssl. As i is wll known, ships during manouvrs can xprinc larg flucuaions of h rquird shaf powr, spcially in h cas of vry igh urning circls a h maximum ruddr angls; hs flucuaions can lad o a considrabl incras of h shaf powr, or shaf orqu if propllr rvoluions ar kp consan, up o and ovr 100% of h sady valus in a sraigh cours. Morovr, during a igh urning circl of a winscrw ship, h orqu flucuaions of IX HSMV Napls 25-27 May 2011 5
h wo shafs can b significanly diffrn, if compard bwn hm (Alosol al. 2008). Ths ffcs could b ponially dangrous, if no corrcly prdicd and card for, in cas of som paricular kinds of propulsion plan, in which for insanc wo shafs ar powrd by h sam prim movr via a uniqu rducion gar, lik in h considrd CODLAG sysm bu also for CODAG sysms (s Fig. 9). For his rason, i was dcidd o implmn in h conrollr layou also a spcific funcion abl o cancl significan orqu unbalancs of h wo shafs, by proprly acing on ach propllr pich (in Fig. 10 his paricular funcion is rprsnd by h block pich adjusmn ). 4 CONCLUDING REMARKS In his papr, svral aspcs rgarding auomaion dsign procdurs and paricular conrol funcions ar discussd. RT HIL simulaion is a dsign approach alrady usd sinc svral yars for auomoiv conrol sysms and rcnly inroducd by Sasma S.p.A. also for naval applicaions, by using mahmaical modls dvlopd a Gnoa Univrsiy. By mans of his powrful chniqu, i is possibl o plan and s nw propulsion conrol soluions for mor and mor complx propulsion sysms, abl o manag high powr ngins, as marin gas urbins, for diffrn propulsion condiions. On h basis of h conrol schms discussd in his papr, a modrn marin propulsion conrol for fas vssl applicaion should b characrisd by h following capabiliis: - Tradiional shaf spd rgulaion in sandard condiions; - Propr auo-adapiv ramps, dpnding on ship spd dmand and acing on h lgraph signal, in ordr o provid sof dynamics for h propulsion machinry; - Ovrorqu procions for shaflins and ngins, basd on boh pich propllr adjusmn and ful hrol rducion; - Torqu balanc funcions o assur h sam prformanc of h ngins acing on h sam shaf - Shaf orqu balanc funcions in cas of paricular garboxs having wo oupus, as in h rcn CODLAG or CODAG applicaions. In gnral, h firs hr funcions should provid suprior prformanc, flxibiliy and nrgy fficincy of h propulsion sysm, whil h las wo should hlp a good lvl of mainnanc of h machinry on board. 5 REFERENCES Rana, R.K., Damaodaran, K.A., Kang, H.S., Gokhal S.S. (1996) Govrning of ship propulsion gas urbin ngin in a saway. Procdings of 11 h Ship Conrol Sysms Symposium, Souhampon (UK) 1996. Alosol, M., Bnvnuo, G., Campora, U., Figari, M.: Dynamic prformanc simulaion of a naval propulsion sysm. Procdings of h Summr Compur Simulaion Confrnc, SCSC 2004, San Jos (California) 2004. Alosol, M., Crrui, M., Dubbioso, G., Mnna, A., Viviani, M. (2008) Marin propulsion sysm dynamics during ship manouvrs. Procdings of HIPER 2008 Confrnc, Napls (Ialy) 2008. Alosol, M., Bnvnuo, G., Campora, U., Figari, M. (2009) Ral-im simulaion of a COGAG naval ship propulsion sysm. Journal of Enginring for h Mariim Environmn, Volum 223, Numbr 1/2009: 47-62. Alosol, M., Bnvnuo, G., Campora, U. (2010a) Numrical modlling of h ngins govrnors of a CODLAG propulsion plan. Procdings of h 10 h Inrnaional Confrnc on Marin Scincs and Tchnologis, Varna (Bulgaria) 2010. Alosol, M., Dubbioso, G., Figari, M., Michi S., Millrani Trapani, A., Viviani, M. (2010b) Simulaion of h dynamic bhaviour of a CODLAG propulsion plan. Procdings of Warship 2010 Confrnc, London (UK) 2010. RINA. IX HSMV Napls 25-27 May 2011 6