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Ma actuator amagwiritsidwa ntchito kulikonse ndipo amapanga kayendetsedwe kolamulidwa pogwiritsa ntchito mphamvu yolondola yosonkhezera kapena torque kuti achite ntchito zosiyanasiyana popanga ndi kupanga ma automation a mafakitale. Kufunika kwa ma drive othamanga, ang'onoang'ono komanso ogwira ntchito bwino kukuyendetsa luso pakupanga ma drive. Ma drive a Shape Memory Alloy (SMA) amapereka zabwino zingapo kuposa ma drive wamba, kuphatikiza chiŵerengero champhamvu kwambiri mpaka kulemera. Mu dissertation iyi, actuator yokhala ndi nthenga ziwiri ya SMA idapangidwa yomwe imaphatikiza zabwino za minofu ya nthenga ya machitidwe achilengedwe ndi mawonekedwe apadera a SMA. Kafukufukuyu akufufuza ndikukulitsa ma actuator am'mbuyomu a SMA popanga chitsanzo cha masamu cha actuator yatsopano kutengera dongosolo la waya wa bimodal SMA ndikuyesa mwa kuyesa. Poyerekeza ndi ma drive odziwika kutengera SMA, mphamvu yoyendetsera ya drive yatsopano ndi yokwera kasanu (mpaka 150 N). Kuchepetsa thupi kofananako kuli pafupifupi 67%. Zotsatira za kusanthula kwa sensitivity kwa ma model a masamu ndizothandiza pakusintha magawo a kapangidwe ndikumvetsetsa magawo ofunikira. Kafukufukuyu akuwonetsanso multi-level Nth stage drive yomwe ingagwiritsidwe ntchito kupititsa patsogolo mphamvu. Ma activator a minofu a dipvalerate okhala ndi SMA ali ndi ntchito zosiyanasiyana, kuyambira pakupanga makina odziyimira pawokha mpaka makina operekera mankhwala molondola.
Machitidwe a zamoyo, monga mapangidwe a minofu ya nyama zoyamwitsa, amatha kuyambitsa ma actuator ambiri obisika1. Nyama zoyamwitsa zimakhala ndi mapangidwe osiyanasiyana a minofu, iliyonse imagwira ntchito yake. Komabe, kapangidwe ka minofu ya nyama zoyamwitsa kangagawidwe m'magulu awiri akuluakulu. Parallel ndi pennate. Mu hamstrings ndi ma flexor ena, monga momwe dzinalo likusonyezera, minofu yofanana imakhala ndi ulusi wa minofu wofanana ndi tendon yapakati. Unyolo wa ulusi wa minofu umalumikizidwa bwino ndi minofu yolumikizana yozungulira. Ngakhale kuti minofu iyi imanenedwa kuti ili ndi ulendo waukulu (kufupikitsa peresenti), mphamvu yawo yonse ya minofu ndi yochepa kwambiri. Mosiyana ndi zimenezi, mu minofu ya triceps calf2 (lateral gastrocnemius (GL)3, medial gastrocnemius (GM)4 ndi soleus (SOL)) ndi extensor femoris (quadriceps)5,6 minofu ya pennate imapezeka mu minofu iliyonse7. Mu kapangidwe ka pinnate, ulusi wa minofu mu minofu ya bipennate ulipo mbali zonse ziwiri za tendon yapakati pa ngodya zowongoka (pinnate angles). Pennate imachokera ku liwu lachilatini lakuti "penna", lomwe limatanthauza "cholembera", ndipo, monga momwe chithunzi 1 chikusonyezera, mawonekedwe ake ndi ofanana ndi nthenga. Ulusi wa minofu ya pennate ndi waufupi komanso wopingasa ku mzere wautali wa minofu. Chifukwa cha kapangidwe ka pinnate, kuyenda konse kwa minofu iyi kumachepa, zomwe zimapangitsa kuti zigawo zopingasa ndi zazitali za njira yofupikitsira minofu zichepe. Kumbali ina, kuyambika kwa minofu iyi kumabweretsa mphamvu yayikulu ya minofu yonse chifukwa cha momwe dera lopingasa limayezedwera. Chifukwa chake, pa gawo linalake lopingasa, minofu ya pennate idzakhala yolimba ndipo imapanga mphamvu zambiri kuposa minofu yokhala ndi ulusi wofanana. Mphamvu zopangidwa ndi ulusi uliwonse zimapanga mphamvu za minofu pamlingo waukulu kwambiri mu minofu imeneyo. Kuphatikiza apo, ili ndi zinthu zapadera monga kuchepa mwachangu, kuteteza kuwonongeka kwa kukoka, ndi kutsamira. Imasintha ubale pakati pa kulowetsa kwa ulusi ndi kutulutsa mphamvu kwa minofu pogwiritsa ntchito mawonekedwe apadera komanso zovuta za kapangidwe ka ulusi wogwirizana ndi mizere ya minofu.
Zomwe zawonetsedwa ndi zithunzi za mapangidwe a SMA-based actuator omwe alipo pokhudzana ndi kapangidwe ka minofu ya bimodal, mwachitsanzo (a), zomwe zikuyimira kuyanjana kwa mphamvu yogwira momwe chipangizo chooneka ngati dzanja choyendetsedwa ndi mawaya a SMA chimayikidwa pa robot yoyenda yoyendetsedwa ndi mawilo awiri9,10. , (b) Robotic orbital prosthesis yokhala ndi SMA spring-loaded orbital prosthesis yokhazikika motsutsana. Malo a diso lopangira opaleshoni amayendetsedwa ndi chizindikiro chochokera ku minofu ya maso ya diso11, (c) SMA actuators ndi abwino kwambiri pakugwiritsa ntchito pansi pa madzi chifukwa cha kuyankha kwawo pafupipafupi komanso bandwidth yochepa. Mu kapangidwe kameneka, ma actuator a SMA amagwiritsidwa ntchito popanga kayendedwe ka mafunde poyesa kayendedwe ka nsomba, (d) Ma actuator a SMA amagwiritsidwa ntchito popanga loboti yowunikira mapaipi yaying'ono yomwe ingagwiritse ntchito mfundo yoyendera ya inch worm, yolamulidwa ndi kayendedwe ka mawaya a SMA mkati mwa njira 10, (e) ikuwonetsa njira ya ulusi wa minofu yokhotakhota ndikupanga mphamvu yokhotakhota mu minofu ya gastrocnemius, (f) ikuwonetsa mawaya a SMA okonzedwa ngati ulusi wa minofu mu kapangidwe ka minofu yozungulira.
Ma actuator akhala gawo lofunika kwambiri la makina chifukwa cha ntchito zawo zosiyanasiyana. Chifukwa chake, kufunikira kwa ma drive ang'onoang'ono, othamanga komanso ogwira ntchito bwino kumakhala kofunikira kwambiri. Ngakhale kuti ali ndi ubwino, ma drive achikhalidwe atsimikizira kuti ndi okwera mtengo komanso otenga nthawi kuti azisamalira. Ma actuator a hydraulic ndi pneumatic ndi ovuta komanso okwera mtengo ndipo amatha kuwonongeka, mavuto a mafuta komanso kulephera kwa zigawo. Poyankha kufunikira, cholinga chachikulu ndikukhazikitsa ma actuator otsika mtengo, okonzedwa bwino komanso apamwamba kutengera zida zanzeru. Kafukufuku wopitilira akuyang'ana ma actuator okhala ndi mawonekedwe a alloy (SMA) kuti akwaniritse izi. Ma actuator osinthika ndi apadera chifukwa amaphatikiza ma actuator ambiri osiyana m'ma subsystems ovuta a macroscale kuti apereke magwiridwe antchito owonjezereka komanso okulirapo. Pachifukwa ichi, minofu ya munthu yomwe yafotokozedwa pamwambapa imapereka chitsanzo chabwino kwambiri cha ma actuation okhala ndi zigawo zambiri. Kafukufuku wapano akufotokoza za drive ya SMA ya magawo ambiri yokhala ndi zinthu zingapo zoyendetsera payekha (ma waya a SMA) zogwirizana ndi ulusi womwe ulipo mu minofu ya bimodal, zomwe zimapangitsa kuti drive yonse igwire bwino ntchito.
Cholinga chachikulu cha actuator ndikupanga mphamvu yamakina monga mphamvu ndi kusuntha mwa kusintha mphamvu yamagetsi. Ma alloys okumbukira mawonekedwe ndi gulu la zinthu "zanzeru" zomwe zimatha kubwezeretsa mawonekedwe awo kutentha kwambiri. Pakakhala katundu wambiri, kuwonjezeka kwa kutentha kwa waya wa SMA kumapangitsa kuti mawonekedwe abwererenso, zomwe zimapangitsa kuti mphamvu yamagetsi ikhale yowonjezereka poyerekeza ndi zinthu zosiyanasiyana zanzeru zomwe zimalumikizidwa mwachindunji. Nthawi yomweyo, pansi pa katundu wamakina, ma SMA amakhala ofooka. Pazifukwa zina, katundu wozungulira amatha kuyamwa ndikutulutsa mphamvu yamakina, zomwe zimapangitsa kuti mawonekedwe asinthe. Makhalidwe apaderawa amapangitsa SMA kukhala yoyenera masensa, kugwedezeka kwa kugwedezeka komanso makamaka ma actuator12. Poganizira izi, pakhala kafukufuku wambiri pa ma drive ozikidwa pa SMA. Tiyenera kudziwa kuti ma actuator ozikidwa pa SMA adapangidwa kuti apereke kayendedwe kosinthika komanso kozungulira pa ntchito zosiyanasiyana13,14,15. Ngakhale ma actuator ena ozungulira apangidwa, ofufuza ali ndi chidwi kwambiri ndi ma actuator ozikidwa pa mzere. Ma actuator ozikidwa pa mzere awa akhoza kugawidwa m'mitundu itatu ya ma actuator: ma actuator amtundu umodzi, osunthika ndi ma differential 16. Poyamba, ma hybrid drive adapangidwa pamodzi ndi ma SMA ndi ma frequency ena odziwika. Chitsanzo chimodzi cha SMA-based hybrid linear actuator ndi kugwiritsa ntchito waya wa SMA wokhala ndi mota ya DC kuti apereke mphamvu yotulutsa ya pafupifupi 100 N ndi kusuntha kwakukulu17.
Chimodzi mwa zinthu zoyamba zomwe zachitika mu ma drive ozikidwa pa SMA chinali SMA parallel drive. Pogwiritsa ntchito mawaya angapo a SMA, SMA-based parallel drive idapangidwa kuti iwonjezere mphamvu ya drive poyika mawaya onse a SMA18 motsatizana. Kulumikizana kwa ma actuator otsatizana sikuti kumangofunika mphamvu zambiri, komanso kumachepetsa mphamvu yotulutsa ya waya umodzi. Vuto lina la ma actuator otsatizana a SMA ndi kuyenda kochepa komwe angakwaniritse. Pofuna kuthetsa vutoli, chingwe cha SMA chinapangidwa chokhala ndi mtanda wosinthasintha wopotoka kuti chiwonjezere kusuntha ndikupeza kuyenda kolunjika, koma sichinapange mphamvu zambiri19. Kapangidwe kofewa kosinthika ndi nsalu za ma robot ozikidwa pa ma alloys okumbukira mawonekedwe zapangidwa makamaka kuti ziwonjezere mphamvu20,21,22. Pa ntchito zomwe liwiro lalikulu likufunika, mapampu oyendetsedwa ndi compact anenedwa pogwiritsa ntchito ma thin film SMA ozikidwa pa micropump ozikidwa pa 23. Kuchuluka kwa ma drive a thin film SMA membrane ndi chinthu chofunikira kwambiri pakulamulira liwiro la driver. Chifukwa chake, ma SMA linear motors ali ndi yankho labwino kwambiri kuposa ma SMA spring kapena rod motors. Ma roboti ofewa ndi ukadaulo wogwirira ndi ntchito zina ziwiri zomwe zimagwiritsa ntchito ma actuator ozikidwa pa SMA. Mwachitsanzo, kuti alowe m'malo mwa actuator yokhazikika yomwe imagwiritsidwa ntchito mu 25 N space clamp, adapanga actuator yofanana ndi mawonekedwe 24. Pankhani ina, actuator yofewa ya SMA idapangidwa pogwiritsa ntchito waya wokhala ndi matrix yolumikizidwa yomwe imatha kupanga mphamvu yokoka ya 30 N. Chifukwa cha mawonekedwe awo amakina, ma SMA amagwiritsidwanso ntchito popanga ma actuator omwe amatsanzira zochitika zamoyo. Chimodzi mwa zinthuzi chikuphatikizapo loboti ya maselo 12 yomwe ndi biomimetic ya chamoyo chonga nyongolotsi ya padziko lapansi yokhala ndi SMA kuti ipange kayendedwe ka sinusoidal kuti iphulike26,27.
Monga tanenera kale, pali malire a mphamvu yayikulu yomwe ingapezeke kuchokera ku ma actuator omwe alipo a SMA. Pofuna kuthana ndi vutoli, kafukufukuyu akuwonetsa kapangidwe ka minofu ya bimodal ya biomimetic. Yoyendetsedwa ndi waya wa alloy wa mawonekedwe. Imapereka dongosolo logawa lomwe limaphatikizapo mawaya angapo a alloy a mawonekedwe. Mpaka pano, palibe ma actuator opangidwa ndi SMA omwe ali ndi kapangidwe kofanana komwe kanenedwa m'mabuku. Dongosolo lapadera komanso latsopanoli lozikidwa pa SMA linapangidwa kuti liphunzire machitidwe a SMA panthawi yolumikizana kwa minofu ya bimodal. Poyerekeza ndi ma actuator omwe alipo a SMA, cholinga cha kafukufukuyu chinali kupanga actuator ya dipvalerate ya biomimetic kuti ipange mphamvu zazikulu kwambiri pang'onopang'ono. Poyerekeza ndi ma drive oyendetsedwa ndi ma stepper motor omwe amagwiritsidwa ntchito mu HVAC building automation ndi control systems, kapangidwe ka bimodal drive ka SMA komwe kamaperekedwa kamachepetsa kulemera kwa makina oyendetsa ndi 67%. Mu zotsatirazi, mawu oti "minofu" ndi "drive" amagwiritsidwa ntchito mosinthana. Kafukufukuyu akufufuza kuyerekezera kwa multiphysics kwa drive yotere. Khalidwe la makina a machitidwe otere laphunziridwa ndi njira zoyesera komanso zowunikira. Kugawa kwa mphamvu ndi kutentha kunafufuzidwanso pa voteji yolowera ya 7 V. Pambuyo pake, kusanthula kwa parametric kunachitika kuti timvetsetse bwino ubale womwe ulipo pakati pa magawo ofunikira ndi mphamvu yotulutsa. Pomaliza, ma actuator otsogola awonedwa ndipo zotsatira za gawo lotsogola zaperekedwa ngati malo omwe angakhalepo mtsogolo mwa ma actuator osakhala a maginito ogwiritsira ntchito ma prosthetic. Malinga ndi zotsatira za kafukufuku amene atchulidwa pamwambapa, kugwiritsa ntchito kapangidwe ka gawo limodzi kumapanga mphamvu zosachepera kanayi kapena kasanu kuposa ma actuator okhazikika pa SMA omwe anenedwa. Kuphatikiza apo, mphamvu yoyendetsera yomweyi yopangidwa ndi drive ya magawo ambiri yawonetsedwa kuti ndi yoposa nthawi khumi kuposa ma drive wamba okhazikika pa SMA. Kenako kafukufukuyu amafotokoza magawo ofunikira pogwiritsa ntchito kusanthula kwa chidwi pakati pa mapangidwe osiyanasiyana ndi zosintha zolowera. Kutalika koyambirira kwa waya wa SMA (\(l_0\)), ngodya ya pinnate (\(\alpha\)) ndi chiwerengero cha zingwe imodzi (n) mu chingwe chilichonse chili ndi zotsatira zoyipa kwambiri pa kukula kwa mphamvu yoyendetsera, pomwe voteji yolowera (mphamvu) inapezeka kuti ikugwirizana bwino.
Waya wa SMA umasonyeza mawonekedwe a kukumbukira (SME) omwe amapezeka m'banja la nickel-titanium (Ni-Ti). Kawirikawiri, ma SMA amasonyeza magawo awiri otengera kutentha: gawo lotsika kutentha ndi gawo lotentha kwambiri. Magawo onsewa ali ndi mawonekedwe apadera chifukwa cha kukhalapo kwa mapangidwe osiyanasiyana a kristalo. Mu gawo la austenite (gawo lotentha kwambiri) lomwe limakhala pamwamba pa kutentha kosinthika, zinthuzo zimakhala ndi mphamvu zambiri ndipo sizimapangidwa bwino zikamalemera. Aloyiyo imagwira ntchito ngati chitsulo chosapanga dzimbiri, kotero imatha kupirira kupsinjika kwakukulu kwa actuation. Pogwiritsa ntchito mphamvu iyi ya aloyi a Ni-Ti, mawaya a SMA amapendekeka kuti apange actuator. Mitundu yoyenera yowunikira imapangidwa kuti imvetsetse njira zoyambira za kutentha kwa SMA mothandizidwa ndi magawo osiyanasiyana ndi ma geometries osiyanasiyana. Mgwirizano wabwino unapezeka pakati pa zotsatira zoyesera ndi zowunikira.
Kafukufuku woyeserera adachitika pa chitsanzo chomwe chawonetsedwa pa Chithunzi 9a kuti awone momwe ma drive awiri amagwirira ntchito kutengera SMA. Zinthu ziwiri mwa izi, mphamvu yopangidwa ndi drive (mphamvu ya minofu) ndi kutentha kwa waya wa SMA (kutentha kwa SMA), zidayesedwa mwa kuyesa. Pamene kusiyana kwa magetsi kukuwonjezeka kutalika konse kwa waya mu drive, kutentha kwa waya kumawonjezeka chifukwa cha mphamvu ya kutentha ya Joule. Voltage yolowera idagwiritsidwa ntchito m'ma cycle awiri a 10-s (omwe akuwonetsedwa ngati madontho ofiira pa Chithunzi 2a, b) ndi nthawi yozizira ya 15-s pakati pa kuzungulira kulikonse. Mphamvu yoletsa idayesedwa pogwiritsa ntchito piezoelectric strain gauge, ndipo kufalikira kwa kutentha kwa waya wa SMA kudayang'aniridwa nthawi yeniyeni pogwiritsa ntchito kamera ya LWIR yapamwamba kwambiri yasayansi (onani makhalidwe a zida zomwe zagwiritsidwa ntchito pa Table 2). zikuwonetsa kuti panthawi yamagetsi apamwamba, kutentha kwa waya kumawonjezeka pang'onopang'ono, koma pamene palibe mphamvu yamagetsi yomwe ikuyenda, kutentha kwa waya kumapitirira kutsika. Mu njira yoyesera yomwe ilipo pano, kutentha kwa waya wa SMA kunatsika panthawi yozizira, koma kunali pamwamba pa kutentha kozungulira. Pa chithunzi 2e chikuwonetsa chithunzi cha kutentha kwa waya wa SMA komwe kunatengedwa kuchokera ku kamera ya LWIR. Kumbali ina, pa chithunzi 2a chikuwonetsa mphamvu yoletsa yomwe imapangidwa ndi makina oyendetsa. Mphamvu ya minofu ikapitirira mphamvu yobwezeretsa ya kasupe, mkono wosunthika, monga momwe zasonyezedwera pa Chithunzi 9a, umayamba kuyenda. Mphamvu yosunthika ikangoyamba, mkono wosunthika umakumana ndi sensa, ndikupanga mphamvu ya thupi, monga momwe zasonyezedwera pa chithunzi 2c, d. Kutentha kwakukulu kukayandikira \(84\,^{\circ}\hbox {C}\), mphamvu yayikulu yomwe imawonedwa ndi 105 N.
Chithunzichi chikuwonetsa zotsatira za kuyesa kwa kutentha kwa waya wa SMA ndi mphamvu yopangidwa ndi actuator ya SMA-based bimodal panthawi ya kuzungulira kawiri. Voltage yolowera imagwiritsidwa ntchito m'magawo awiri a masekondi 10 (omwe akuwonetsedwa ngati madontho ofiira) ndi nthawi yozizira ya masekondi 15 pakati pa kuzungulira kulikonse. Waya wa SMA womwe unagwiritsidwa ntchito pakuyeseraku unali waya wa Flexinol wa 0.51 mm m'mimba mwake wochokera ku Dynalloy, Inc. (a) Chithunzichi chikuwonetsa mphamvu yoyesera yomwe idapezeka m'magawo awiri, (c, d) chikuwonetsa zitsanzo ziwiri zodziyimira pawokha za momwe ma actuator a mkono amayendera pa PACEline CFT/5kN piezoelectric force transducer, (b) chithunzichi chikuwonetsa kutentha kwakukulu kwa waya wonse wa SMA panthawi ya kuzungulira kawiri, (e) chikuwonetsa chithunzi cha kutentha chomwe chatengedwa kuchokera ku waya wa SMA pogwiritsa ntchito kamera ya FLIR ResearchIR software LWIR. Ma parameter a geometric omwe aganiziridwa mu kuyesaku aperekedwa mu Gome loyamba.
Zotsatira za kuyeserera kwa chitsanzo cha masamu ndi zotsatira za kuyesa zimayerekezeredwa pansi pa mkhalidwe wa voltage yolowera ya 7V, monga momwe zasonyezedwera pa Chithunzi 5. Malinga ndi zotsatira za kusanthula kwa parametric komanso kuti tipewe kuthekera kwa kutentha kwambiri kwa waya wa SMA, mphamvu ya 11.2 W idaperekedwa ku actuator. Mphamvu ya DC yokonzedwa idagwiritsidwa ntchito kupereka 7V ngati voltage yolowera, ndipo mphamvu yamagetsi ya 1.6A idayesedwa kudutsa waya. Mphamvu yopangidwa ndi drive ndi kutentha kwa SDR zimawonjezeka pamene mphamvu yamagetsi ikugwiritsidwa ntchito. Ndi voltage yolowera ya 7V, mphamvu yayikulu yotulutsa yomwe idapezeka kuchokera ku zotsatira za kuyeserera ndi zotsatira za kuyesa kwa kuzungulira koyamba ndi 78 N ndi 96 N, motsatana. Mu kuzungulira kwachiwiri, mphamvu yayikulu yotulutsa ya zotsatira za kuyeserera ndi kuyesa inali 150 N ndi 105 N, motsatana. Kusiyana pakati pa muyeso wa mphamvu yotseka ndi deta yoyesera kungakhale chifukwa cha njira yomwe imagwiritsidwa ntchito poyesa mphamvu yotseka. Zotsatira za kuyesa zomwe zawonetsedwa pa chithunzi. 5a ikugwirizana ndi muyeso wa mphamvu yotseka, yomwe idayesedwa pamene shaft yoyendetsa inali yolumikizana ndi transducer ya PACEline CFT/5kN piezoelectric force, monga momwe zasonyezedwera pachithunzi cha 2s. Chifukwa chake, shaft yoyendetsa ikapanda kulumikizana ndi sensa yamphamvu kumayambiriro kwa malo ozizira, mphamvuyo nthawi yomweyo imakhala zero, monga momwe zasonyezedwera pachithunzi cha 2d. Kuphatikiza apo, magawo ena omwe amakhudza kupangika kwa mphamvu m'magawo otsatira ndi ma values a nthawi yozizira ndi coefficient ya convective heat transfer mumzere wapitawo. Kuchokera pachithunzi cha 2b, zitha kuwoneka kuti pambuyo pa nthawi yozizira ya masekondi 15, waya wa SMA sunafike kutentha kwa chipinda ndipo motero unali ndi kutentha koyambirira kokwera (\(40\,^{\circ }\hbox {C}\)) mumzere wachiwiri woyendetsa poyerekeza ndi mzere woyamba (\(25\, ^{\circ}\hbox {C}\)). Motero, poyerekeza ndi kuzungulira koyamba, kutentha kwa waya wa SMA panthawi yachiwiri yotenthetsera kumafika kutentha koyambirira kwa austenite (\(A_s\)) ndipo kumakhalabe mu nthawi yosinthira nthawi yayitali, zomwe zimapangitsa kuti pakhale kupsinjika ndi mphamvu. Kumbali ina, kugawa kutentha panthawi yotenthetsera ndi kuzizira komwe kumapezeka kuchokera ku zoyeserera ndi zoyeserera kuli ndi kufanana kwakukulu ndi zitsanzo kuchokera ku kusanthula kwa thermographic. Kusanthula koyerekeza kwa deta ya kutentha kwa waya wa SMA kuchokera ku zoyeserera ndi zoyeserera kunawonetsa kusinthasintha panthawi yotenthetsera ndi kuzizira komanso mkati mwa kulekerera kovomerezeka kwa deta yoyesera. Kutentha kwakukulu kwa waya wa SMA, komwe kumapezeka kuchokera ku zotsatira za kuyerekezera ndi zoyeserera za kuzungulira koyamba, ndi \(89\,^{\circ }\hbox {C}\) ndi \(75\,^{\circ }\hbox {C }\, motsatana ), ndipo mu kuzungulira kwachiwiri kutentha kwakukulu kwa waya wa SMA ndi \(94\,^{\circ }\hbox {C}\) ndi \(83\,^{\circ }\ hbox {C}\). Chitsanzo chopangidwa mwaluso chikutsimikizira momwe mawonekedwe amakhudzira. Udindo wa kutopa ndi kutentha kwambiri sunaganiziridwe mu ndemanga iyi. Mtsogolomu, chitsanzochi chidzasinthidwa kuti chiphatikizepo mbiri ya kupsinjika kwa waya wa SMA, zomwe zimapangitsa kuti chikhale choyenera kwambiri pa ntchito zauinjiniya. Mphamvu yotulutsa ma drive ndi ma temperature plots a SMA omwe apezeka kuchokera ku Simulink block ali mkati mwa kulekerera kovomerezeka kwa deta yoyesera pansi pa mkhalidwe wa 7 V. Izi zikutsimikizira kulondola ndi kudalirika kwa chitsanzo cha masamu chopangidwa.
Chitsanzo cha masamu chinapangidwa mu MathWorks Simulink R2020b pogwiritsa ntchito ma equation oyambira omwe afotokozedwa mu gawo la Njira. Pa chithunzi 3b chikuwonetsa chithunzi cha block cha chitsanzo cha masamu cha Simulink. Chitsanzocho chinayesedwa kuti chikhale ndi 7V input voltage pulse monga momwe zasonyezedwera pa Chithunzi 2a, b. Ma values a parameters omwe amagwiritsidwa ntchito mu simulation alembedwa mu Table 1. Zotsatira za simulation ya transient processes zaperekedwa mu Zithunzi 1 ndi 1. Zithunzi 3a ndi 4. Mu chithunzi 4a,b chikuwonetsa voltage yomwe imayambitsa mu waya wa SMA ndi mphamvu yomwe imapangidwa ndi actuator ngati ntchito ya nthawi. Pakusintha kwa reverse (kutentha), pamene kutentha kwa waya wa SMA, \(T < A_s^{\prime}\) (kutentha koyambira kwa austenite), kuchuluka kwa kusintha kwa voliyumu ya martensite (\(\dot{\xi }\)) kudzakhala zero. Pakusintha kwa reverse (kutentha), pamene kutentha kwa waya wa SMA, \(T < A_s^{\prime}\) (kutentha koyambira kwa austenite), kuchuluka kwa kusintha kwa voliyumu ya martensite (\(\dot{\ xi }\)) kudzakhala zero. Во время обратного превращения (нагрева), когда температура проволоки SMA, \(T < A_s^{\prime}\) (температура начала аустенитной модинацы, напряжением), скорость изменения объемной доли мартенсита (\(\dot{\ xi xi }\)) будет равно нулю. Pakusintha kwa reverse (kutentha), pamene kutentha kwa waya wa SMA, \(T < A_s^{\prime}\) (kutentha koyambirira kwa austenite), kuchuluka kwa kusintha kwa gawo la voliyumu ya martensite (\(\dot{\ xi }\ )) kudzakhala zero.在反向转变（加热）过程中，当SMA 线温度\(T < A_s^{\prime}\))（应力修正奥氏体相起始温度）时，马氏体体积分数的变化率（\(\xi}\) .在 反向 转变 （加热） 中, 当 当 线 温度 \ (t
(a) Zotsatira zoyeserera zomwe zikuwonetsa kufalikira kwa kutentha ndi kutentha kwa junction komwe kumabwera chifukwa cha kupsinjika mu actuator ya divalerate yochokera ku SMA. Kutentha kwa waya kukadutsa kutentha kwa austenite kusintha mu gawo lotenthetsera, kutentha kwa austenite kusintha kosinthidwa kumayamba kuwonjezeka, ndipo mofananamo, kutentha kwa waya ndodo kukadutsa kutentha kwa martensitic kusintha mu gawo lozizira, kutentha kwa martensitic kusintha kumachepa. SMA yowunikira njira yoyendetsera. (Kuti muwone mwatsatanetsatane za subsystem iliyonse ya Simulink model, onani gawo la appendix la fayilo yowonjezera.)
Zotsatira za kusanthula kwa magawo osiyanasiyana a parameter zikuwonetsedwa pa ma cycle awiri a 7V input voltage (ma cycle otenthetsera masekondi 10 ndi ma cycle oziziritsa masekondi 15). Pomwe (ac) ndi (e) zikuwonetsa kugawa pakapita nthawi, kumbali inayi, (d) ndi (f) zikuwonetsa kugawa ndi kutentha. Pazinthu zomwe zikuphatikizidwa, kupsinjika kwakukulu komwe kumawonedwa ndi 106 MPa (zosakwana 345 MPa, mphamvu ya waya), mphamvu ndi 150 N, kusuntha kwakukulu ndi 270 µm, ndipo gawo locheperako la voliyumu ya martensitic ndi 0.91. Kumbali inayi, kusintha kwa kupsinjika ndi kusintha kwa voliyumu ya martensite ndi kutentha ndizofanana ndi makhalidwe a hysteresis.
Kufotokozera komweku kukugwiranso ntchito pa kusintha kwachindunji (kuzizira) kuchokera ku gawo la austenite kupita ku gawo la martensite, komwe kutentha kwa waya wa SMA (T) ndi kutentha komaliza kwa gawo la martensite losinthidwa ndi stress (\(M_f^{\prime}\ )) kuli bwino kwambiri. Pa chithunzi 4d,f chikuwonetsa kusintha kwa kupsinjika komwe kwachitika (\(\sigma\)) ndi gawo la voliyumu ya martensite (\(\xi\)) mu waya wa SMA monga momwe kusintha kwa kutentha kwa waya wa SMA (T) kumakhalira, pamayendedwe onse awiri oyendetsera. Pa chithunzi 3a chikuwonetsa kusintha kwa kutentha kwa waya wa SMA pakapita nthawi kutengera kugunda kwa voliyumu yolowera. Monga momwe tikuonera pachithunzichi, kutentha kwa waya kumapitilira kuwonjezeka popereka gwero la kutentha pa zero voltage ndi kuzizira kotsatira kwa convective. Pa kutentha, kusintha kwa martensite kukhala gawo la austenite kumayamba pamene kutentha kwa waya wa SMA (T) kudutsa kutentha kwa austenite nucleation komwe kwakonzedwa ndi kupsinjika (\(A_s^{\prime}\)). Pa gawoli, waya wa SMA umakanikizidwa ndipo chowunikira chimapanga mphamvu. Komanso panthawi yozizira, pamene kutentha kwa waya wa SMA (T) kudutsa kutentha kwa nucleation kwa gawo la martensite losinthidwa ndi kupsinjika (\(M_s^{\prime}\)) pamakhala kusintha kwabwino kuchokera ku gawo la austenite kupita ku gawo la martensite. Mphamvu yoyendetsera imachepa.
Mbali zazikulu za khalidwe la bimodal drive kutengera SMA zitha kupezeka kuchokera ku zotsatira za simulation. Pankhani ya voltage pulse input, kutentha kwa waya wa SMA kumawonjezeka chifukwa cha Joule heating effect. Mtengo woyambirira wa martensite volume fraction (\(\xi\)) wayikidwa ku 1, popeza zinthuzo poyamba zili mu gawo la martensitic mokwanira. Pamene waya ukupitirira kutentha, kutentha kwa waya wa SMA kumaposa kutentha kwa austenite nucleation komwe kumakonzedwa ndi stress-corrected \(A_s^{\prime}\), zomwe zimapangitsa kuchepa kwa martensite volume fraction, monga momwe zasonyezedwera pa Chithunzi 4c. Kuphatikiza apo, pa chithunzi 4e pakuwonetsa kufalikira kwa ma strokes a actuator munthawi, ndipo pa chithunzi 5 - mphamvu yoyendetsera ngati ntchito ya nthawi. Dongosolo lofananira la ma equation limaphatikizapo kutentha, martensite volume fraction, ndi kupsinjika komwe kumachitika mu waya, zomwe zimapangitsa kuti waya wa SMA uchepe ndi mphamvu yopangidwa ndi actuator. Monga momwe zasonyezedwera pa chithunzi. Kusintha kwa 4d,f, voltage ndi kutentha ndi martensite voliyumu ya gawo ndi kutentha kumagwirizana ndi mawonekedwe a hysteresis a SMA mu chitsanzo choyerekeza pa 7 V.
Kuyerekeza kwa magawo oyendetsera galimoto kunapezeka kudzera mu kuyesa ndi kuwerengera kosanthula. Mawayawo adayikidwa pa voteji yolowera ya 7 V kwa masekondi 10, kenako adazizidwa kwa masekondi 15 (gawo lozizira) m'magawo awiri. Ngodya ya pinnate imayikidwa pa \(40^{\circ}\) ndipo kutalika koyambirira kwa waya wa SMA mu mwendo uliwonse wa pin kumayikidwa pa 83mm. (a) Kuyeza mphamvu yoyendetsera galimoto ndi selo yonyamula katundu (b) Kuyang'anira kutentha kwa waya ndi kamera ya infrared yotentha.
Kuti timvetse momwe ma parameter akuthupi amakhudzira mphamvu yopangidwa ndi drive, kusanthula kwa kukhudzidwa kwa chitsanzo cha masamu ku ma parameter osankhidwa akuthupi kunachitika, ndipo ma parameterwo adasankhidwa malinga ndi kukhudzidwa kwawo. Choyamba, zitsanzo za ma parameter a chitsanzocho zidachitika pogwiritsa ntchito mfundo zoyesera zopangira zomwe zidatsata kugawa kofanana (onani Gawo Lowonjezera pa Kusanthula kwa Kukhudzidwa). Pankhaniyi, ma parameter a chitsanzocho akuphatikizapo voltage yolowera (\(V_{in}\)), kutalika kwa waya wa SMA woyambirira (\(l_0\)), ngodya ya makona atatu (\(\alpha\)), bias spring constant (\( K_x\ )), convective heat transfer coefficient (\(h_T\)) ndi chiwerengero cha nthambi za unimodal (n). Mu gawo lotsatira, mphamvu ya minofu yapamwamba idasankhidwa ngati chofunikira pakupanga kafukufuku ndipo zotsatira za parametric za seti iliyonse ya zosintha pa mphamvu zidapezeka. Ma tornado plots a kusanthula kwa kukhudzidwa adachokera ku ma coefficients ogwirizana pa parameter iliyonse, monga momwe zasonyezedwera mu Chithunzi 6a.
(a) Ma coefficient a correlation values a ma model parameter ndi momwe amakhudzira mphamvu yayikulu yotulutsa ya magulu 2500 apadera a ma model parameter omwe ali pamwambapa akuwonetsedwa mu tornado plot. Chithunzichi chikuwonetsa kuyanjana kwa zizindikiro zingapo. N'zoonekeratu kuti \(V_{in}\) ndiye parameter yokhayo yokhala ndi positive correlation, ndipo \(l_0\) ndiye parameter yokhala ndi negative correlation yapamwamba kwambiri. Zotsatira za ma parameter osiyanasiyana m'magulu osiyanasiyana pa peak muscle streak strength zikuwonetsedwa mu (b, c). \(K_x\) zimayambira pa 400 mpaka 800 N/m ndipo n zimayambira pa 4 mpaka 24. Voltage (\(V_{in}\)) yasintha kuchokera pa 4V mpaka 10V, kutalika kwa waya (\(l_{0} \)) yasintha kuchokera pa 40 mpaka 100 mm, ndipo ngodya ya mchira (\ (\alpha \)) yasintha kuchokera pa \ (20 - 60 \, ^ {\circ }\).
Pa chithunzi 6a chikuwonetsa chithunzi cha mphepo yamkuntho ya ma coefficients osiyanasiyana okhudzana ndi gawo lililonse ndi zofunikira pa kapangidwe ka mphamvu yoyendetsera mphamvu. Kuchokera pa chithunzi 6a zitha kuwoneka kuti gawo la voltage (\(V_{in}\)) limagwirizana mwachindunji ndi mphamvu yayikulu yotulutsa, ndipo coefficient yosinthira kutentha (\(h_T\)), ngodya yamoto (\(\alpha\)), chokhazikika cha masika osunthika (\(K_x\)) chikugwirizana molakwika ndi mphamvu yotulutsa ndi kutalika koyambirira (\(l_0\)) kwa waya wa SMA, ndipo chiwerengero cha nthambi za unimodal (n) chikuwonetsa mgwirizano wamphamvu wotsutsana Pankhani ya mgwirizano wolunjika Pankhani ya mtengo wapamwamba wa coefficient yolumikizira magetsi (\(V_ {in}\)) chikuwonetsa kuti gawoli lili ndi zotsatira zazikulu pa mphamvu yotulutsa. Kusanthula kwina kofananako kumayesa mphamvu yayikulu poyesa zotsatira za magawo osiyanasiyana m'malo osiyanasiyana a malo awiri owerengera, monga momwe zasonyezedwera pa Chithunzi 6b, c. \(V_{in}\) ndi \(l_0\), \(\alpha\) ndi \(l_0\) ali ndi mapatani ofanana, ndipo graph ikuwonetsa kuti \(V_{in}\) ndi \(\alpha\) ndi \(\alpha\) ali ndi mapatani ofanana. Mitengo yaying'ono ya \(l_0\) imabweretsa mphamvu zapamwamba kwambiri. Ma grafu ena awiri akugwirizana ndi Chithunzi 6a, pomwe n ndi \(K_x\) zimagwirizana molakwika ndipo \(V_{in}\) zimagwirizana bwino. Kusanthula kumeneku kumathandiza kufotokoza ndikusintha magawo okhudzira omwe mphamvu yotulutsa, sitiroko ndi magwiridwe antchito a drive system zitha kusinthidwa kuti zigwirizane ndi zofunikira ndi kugwiritsa ntchito.
Kafukufuku wamakono akuyambitsa ndikufufuza ma drive oyendetsedwa ndi ma N levels. Mu utsogoleri wa magawo awiri, monga momwe zasonyezedwera mu Chithunzi 7a, pomwe m'malo mwa waya uliwonse wa SMA wa actuator yoyamba, dongosolo la bimodal limakwaniritsidwa, monga momwe zasonyezedwera mu chithunzi 9e. Pa chithunzi 7c chikuwonetsa momwe waya wa SMA umazungulira mkono wosunthika (mkono wothandizira) womwe umangoyenda mbali yayitali. Komabe, mkono wosunthika woyamba umapitiliza kuyenda mofanana ndi mkono wosunthika wa actuator ya gawo loyamba la multi-stage. Kawirikawiri, N-stage drive imapangidwa mwa kusintha waya wa \(N-1\) wa gawo la SMA ndi drive yoyamba. Zotsatira zake, nthambi iliyonse imatsanzira drive yoyamba, kupatula nthambi yomwe imagwira wayayo yokha. Mwanjira imeneyi, mapangidwe okhala ndi zisa amatha kupangidwa omwe amapanga mphamvu zomwe zimakhala zazikulu kangapo kuposa mphamvu za ma drive oyamba. Mu kafukufukuyu, pa mulingo uliwonse, kutalika konse kwa waya wa SMA wogwira ntchito wa 1 m kudaganiziridwa, monga momwe zasonyezedwera mu mawonekedwe a tebulo mu Chithunzi 7d. Mphamvu yamagetsi kudzera mu waya uliwonse mu kapangidwe ka unimodal iliyonse ndi prestress ndi voltage zomwe zimachitika mu gawo lililonse la waya wa SMA ndizofanana pamlingo uliwonse. Malinga ndi chitsanzo chathu chowunikira, mphamvu yotulutsa imagwirizanitsidwa bwino ndi mulingo, pomwe kusamuka kumagwirizana molakwika. Nthawi yomweyo, panali kusinthana pakati pa kusamuka ndi mphamvu ya minofu. Monga taonera pachithunzi 7b, pomwe mphamvu yayikulu imafikiridwa mu chiwerengero chachikulu cha zigawo, kusamuka kwakukulu kumawonedwa mu gawo lotsika kwambiri. Pamene mulingo wa hierarchy unayikidwa pa \(N=5\), mphamvu yayikulu ya minofu ya 2.58 kN idapezeka ndi ma stroke awiri omwe adawonedwa \(\upmu\)m. Kumbali ina, kuyendetsa gawo loyamba kumapanga mphamvu ya 150 N pa stroke ya 277 \(\upmu\)m. Ma actuator amitundu yambiri amatha kutsanzira minofu yeniyeni yachilengedwe, komwe minofu yopangidwa yozikidwa pa ma alloys okumbukira mawonekedwe imatha kupanga mphamvu zapamwamba kwambiri ndi mayendedwe olondola komanso abwino. Zofooka za kapangidwe kakang'ono aka ndikuti pamene kayendetsedwe kake kakuwonjezeka, kayendetsedwe kake kamachepa kwambiri ndipo zovuta za njira yopangira ma drive zimawonjezeka.
(a) Dongosolo la actuator la magawo awiri (\(N=2\)) la layered shape memory alloy linear actuator likuwonetsedwa mu kasinthidwe ka bimodal. Chitsanzo chomwe chikuperekedwachi chimachitika posintha waya wa SMA mu actuator ya magawo oyamba ndi actuator ina ya magawo amodzi. (c) Kapangidwe kosinthika ka actuator ya magawo awiri a magawo awiri. (b) Kugawidwa kwa mphamvu ndi kusuntha kutengera kuchuluka kwa milingo kwafotokozedwa. Zapezeka kuti mphamvu yayikulu ya actuator imagwirizana bwino ndi mulingo wa sikelo pa graph, pomwe kukwapula kumagwirizana molakwika ndi mulingo wa sikelo. Mphamvu yamagetsi ndi pre-voltage mu waya uliwonse zimakhalabe zosasintha pamilingo yonse. (d) Gome likuwonetsa kuchuluka kwa ma taps ndi kutalika kwa waya wa SMA (fiber) pa mulingo uliwonse. Makhalidwe a mawaya akuwonetsedwa ndi index 1, ndipo chiwerengero cha nthambi zachiwiri (zina zolumikizidwa ndi mwendo woyamba) chikuwonetsedwa ndi nambala yayikulu kwambiri mu subscript. Mwachitsanzo, pa mlingo 5, \(n_1\) amatanthauza chiwerengero cha mawaya a SMA omwe alipo mu kapangidwe ka bimodal kalikonse, ndipo \(n_5\) amatanthauza chiwerengero cha miyendo yothandizira (yomwe yalumikizidwa ndi mwendo waukulu).
Ofufuza ambiri apereka njira zosiyanasiyana zotsanzira khalidwe la ma SMA ndi kukumbukira mawonekedwe, zomwe zimadalira mphamvu za thermomechanical zomwe zikugwirizana ndi kusintha kwa macroscopic mu kapangidwe ka kristalo komwe kumakhudzana ndi kusintha kwa gawo. Kupanga njira zopangira zinthu ndizovuta kwambiri. Chitsanzo cha phenomenological chomwe chimagwiritsidwa ntchito kwambiri chimaperekedwa ndi Tanaka28 ndipo chimagwiritsidwa ntchito kwambiri mu ntchito zauinjiniya. Chitsanzo cha phenomenological chomwe chinaperekedwa ndi Tanaka [28] chimaganiza kuti gawo la voliyumu la martensite ndi ntchito yowonetsa kutentha ndi kupsinjika. Pambuyo pake, Liang ndi Rogers29 ndi Brinson30 adapereka chitsanzo momwe mphamvu ya kusintha kwa gawo idaganiziridwa kuti ndi ntchito ya cosine ya voltage ndi kutentha, ndi kusintha pang'ono kwa chitsanzocho. Becker ndi Brinson adapereka chitsanzo cha kinetic chozikidwa pa chithunzi cha gawo kuti chitsanzire khalidwe la zipangizo za SMA pansi pa mikhalidwe yokweza mosasamala komanso kusintha pang'ono. Banerjee32 imagwiritsa ntchito njira ya Bekker ndi Brinson31 phase diagram dynamics kuti itsanzire digiri imodzi ya freedom manipulator yopangidwa ndi Elahinia ndi Ahmadian33. Njira za Kinetic zochokera pa ma diagram a gawo, zomwe zimaganizira kusintha kwa magetsi komwe sikuli kofanana ndi kutentha, zimakhala zovuta kuzigwiritsa ntchito mu ntchito zauinjiniya. Elakhinia ndi Ahmadian akuwonetsa zofooka izi za mitundu ya phenomenological yomwe ilipo ndipo akupereka chitsanzo chowonjezera cha phenomenological kuti afufuze ndikutanthauzira machitidwe a kukumbukira mawonekedwe pansi pa zovuta zilizonse zonyamula.
Chitsanzo cha kapangidwe ka waya wa SMA chimapereka kupsinjika (\(\sigma\)), kupsinjika (\(\epsilon\)), kutentha (T), ndi kuchuluka kwa voliyumu ya martensite (\(\xi\)) ya waya wa SMA. Chitsanzo cha phenomenological constitutive chinaperekedwa koyamba ndi Tanaka28 ndipo pambuyo pake chinagwiritsidwa ntchito ndi Liang29 ndi Brinson30. Chochokera mu equation chili ndi mawonekedwe awa:
kumene E ndi gawo lodalira SMA Young's modulus yomwe yapezeka pogwiritsa ntchito \(\displaystyle E=\xi E_M + (1-\xi )E_A\) ndi \(E_A\) ndi \(E_M\) zomwe zikuyimira Young's modulus ndi austenitic ndi martensitic phases, motsatana, ndipo coefficient of thermal expansion imaimiridwa ndi \(\theta _T\). Gawo lothandizira kusintha ndi \(\Omega = -E \epsilon _L\) ndipo \(\epsilon _L\) ndiye mphamvu yayikulu yobwezerezedwanso mu waya wa SMA.
Chiyerekezo cha mphamvu ya gawo chikugwirizana ndi ntchito ya cosine yomwe idapangidwa ndi Liang29 ndipo pambuyo pake idagwiritsidwa ntchito ndi Brinson30 m'malo mwa ntchito yodziwikiratu yomwe idaperekedwa ndi Tanaka28. Chitsanzo cha kusintha kwa gawo ndi chowonjezera cha chitsanzo chomwe chidaperekedwa ndi Elakhinia ndi Ahmadian34 ndipo chasinthidwa kutengera mikhalidwe ya kusintha kwa gawo yomwe idaperekedwa ndi Liang29 ndi Brinson30. Mikhalidwe yomwe imagwiritsidwa ntchito pa chitsanzo cha kusintha kwa gawo ili ndi yovomerezeka pansi pa katundu wovuta wa thermomechanical. Pa mphindi iliyonse ya nthawi, mtengo wa gawo la voliyumu la martensite umawerengedwa potengera equation yokhazikika.
Chiyerekezo cholamulira cha kusinthika, chomwe chimafotokozedwa ndi kusintha kwa martensite kukhala austenite pansi pa kutentha, ndi motere:
kumene \(\xi\) ndi gawo la voliyumu la martensite, \(\xi _M\) ndi gawo la voliyumu la martensite lomwe limapezeka musanatenthe, \(\displaystyle a_A = \pi /(A_f – A_s)\), \( \displaystyle b_A = -a_A/C_A\) ndi \(C_A\) – magawo oyerekeza a curve, kutentha kwa waya wa T – SMA, \(A_s\) ndi \(A_f\) – kuyambira ndi kumapeto kwa gawo la austenite, motsatana, kutentha.
Chiyerekezo chowongolera kusintha mwachindunji, chomwe chikuyimiridwa ndi kusintha kwa gawo la austenite kukhala martensite pansi pa nyengo yozizira, ndi:
kumene \(\xi _A\) ndi gawo la voliyumu ya martensite yomwe imapezeka isanaziziritsidwe, \(\displaystyle a_M = \pi /(M_s – M_f)\), \(\displaystyle b_M = -a_M/C_M\) ndi \ (C_M \) – magawo olumikizira ma curve, kutentha kwa waya wa T – SMA, \(M_s\) ndi \(M_f\) – kutentha koyambirira ndi komaliza kwa martensite, motsatana.
Pambuyo poti ma equation (3) ndi (4) asiyanitsidwa, ma equation osinthika molunjika ndi molunjika amasinthidwa kukhala otsatirawa:
Pakusintha kwa kutsogolo ndi kumbuyo \(\eta _{\sigma}\) ndi \(\eta _{T}\) zimakhala ndi ma values osiyanasiyana. Ma equation oyambira okhudzana ndi \(\eta _{\sigma}\) ndi \(\eta _{T}\) atengedwa ndikukambidwa mwatsatanetsatane mu gawo lina.
Mphamvu ya kutentha yomwe imafunika kuti waya wa SMA utenthe kutentha imachokera ku mphamvu ya kutentha ya Joule. Mphamvu ya kutentha yomwe imayamwa kapena kutulutsidwa ndi waya wa SMA imayimiridwa ndi kutentha kobisika kwa kusintha. Kutayika kwa kutentha mu waya wa SMA kumachitika chifukwa cha kukakamizidwa kwa convection, ndipo chifukwa cha mphamvu yochepa ya kuwala, equation ya mphamvu ya kutentha ndi motere:
Kumene \(m_{wire}\) ndi kulemera konse kwa waya wa SMA, \(c_{p}\) ndi mphamvu yeniyeni ya kutentha kwa SMA, \(V_{in}\) ndi voltage yomwe imagwiritsidwa ntchito pa waya, \(R_{ohm} \ ) – kukana kodalira gawo SMA, komwe kumatanthauzidwa kuti; \(R_{ohm} = (l/A_{cross})[\xi r_M + (1-\xi )r_A]\ ) komwe \(r_M\ ) ndi \(r_A\) ndi kukana kwa gawo la SMA mu martensite ndi austenite, motsatana, \(A_{c}\) ndi malo a pamwamba pa waya wa SMA, \(\Delta H \) ndi alloy yokumbukira mawonekedwe. Kutentha kobisika kwa kusintha kwa waya, T ndi \(T_{\infty}\) ndi kutentha kwa waya wa SMA ndi chilengedwe, motsatana.
Pamene waya wosungira mawonekedwe a chikumbukiro cha mawonekedwe ayambitsidwa, wayayo imakanikizana, ndikupanga mphamvu mu nthambi iliyonse ya kapangidwe ka bimodal kotchedwa fiber force. Mphamvu za ulusi mu chingwe chilichonse cha waya wa SMA pamodzi zimapanga mphamvu ya minofu kuti iyambe kugwira ntchito, monga momwe zasonyezedwera pa Chithunzi 9e. Chifukwa cha kukhalapo kwa kasupe wozungulira, mphamvu yonse ya minofu ya actuator ya Nth multilayer ndi:
Posintha \(N = 1\) kukhala equation (7), mphamvu ya minofu ya prototype yoyamba ya bimodal drive ingapezeke motere:
pomwe n ndi chiwerengero cha miyendo yofanana, \(F_m\) ndi mphamvu ya minofu yopangidwa ndi drive, \(F_f\) ndi mphamvu ya ulusi mu waya wa SMA, \(K_x\) ndi kuuma kwa bias. kasupe, \(\alpha\) ndi ngodya ya katatu, \(x_0\) ndi kuchotsera koyambirira kwa bias spring kuti igwire chingwe cha SMA pamalo okhazikika, ndipo \(\Delta x\) ndi actuator travel.
Kusuntha konse kapena kuyenda kwa drive (\(\Delta x\)) kutengera ndi voltage (\(\sigma\)) ndi kupsinjika (\(\epsilon\)) pa waya wa SMA wa siteji ya Nth, drive imayikidwa (onani Chithunzi. gawo lina la zotuluka):
Ma equation a kinematic amapereka ubale pakati pa kusintha kwa drive (\(\epsilon\)) ndi kusamuka kapena kusamuka (\(\Delta x\)). Kusintha kwa waya wa Arb monga momwe zimakhalira ndi kutalika kwa waya woyamba wa Arb (\(l_0\)) ndi kutalika kwa waya (l) nthawi iliyonse t mu nthambi imodzi ya unimodal ndi motere:
kumene \(l = \sqrt{l_0^2 +(\Delta x_1)^2 – 2 l_0 (\Delta x_1) \cos \alpha _1}\) imapezeka pogwiritsa ntchito fomula ya cosine mu \(\Delta\)ABB ', monga momwe zasonyezedwera pa Chithunzi 8. Pa gawo loyamba la drive (\(N = 1\)), \(\Delta x_1\) ndi \(\Delta x\), ndipo \(\alpha _1\) ndi \(\alpha \) monga momwe zasonyezedwera pa Chithunzi 8, posiyanitsa nthawi kuchokera ku Equation (11) ndikulowetsa mtengo wa l, kuchuluka kwa kupsinjika kungalembedwe motere:
kumene \(l_0\) ndi kutalika koyambirira kwa waya wa SMA, l ndi kutalika kwa waya nthawi iliyonse t mu nthambi imodzi ya unimodal, \(\epsilon\) ndi kusintha komwe kumachitika mu waya wa SMA, ndipo \(\alpha \) ndi ngodya ya katatu, \(\Delta x\) ndi drive offset (monga momwe zasonyezedwera pa Chithunzi 8).
Mapangidwe onse a n okhala ndi chiwongolero chimodzi (\(n=6\) pachithunzichi) alumikizidwa motsatizana ndi \(V_{in}\) ngati voteji yolowera. Gawo I: Chithunzi cha waya wa SMA mu kasinthidwe ka bimodal pansi pa ziro voltage conditions Gawo II: Kapangidwe kolamulidwa kawonetsedwa pomwe waya wa SMA wapanikizika chifukwa cha kusintha kosinthika, monga momwe zasonyezedwera ndi mzere wofiira.
Monga umboni wa lingaliro, chipangizo choyendetsera zinthu cha SMA-based bimodal chinapangidwa kuti chiyese kutengera komwe kwachokera ma equation omwe ali pansi pake ndi zotsatira zoyesera. Chitsanzo cha CAD cha chipangizo choyendetsera zinthu cha bimodal chikuwonetsedwa mu chithunzi 9a. Kumbali inayi, mu chithunzi 9c chikuwonetsa kapangidwe katsopano komwe kaperekedwa kuti pakhale kulumikizana kwa prismatic kozungulira pogwiritsa ntchito chipangizo choyendetsera zinthu cha SMA chokhala ndi magawo awiri chokhala ndi kapangidwe ka bimodal. Zigawo zoyendetsera zidapangidwa pogwiritsa ntchito zowonjezera pa chosindikizira cha Ultimaker 3 Extended 3D. Zipangizo zomwe zimagwiritsidwa ntchito posindikiza zinthu za 3D ndi polycarbonate yomwe ndi yoyenera zinthu zosatentha chifukwa ndi yolimba, yolimba komanso kutentha kwambiri kwa galasi (110-113 \(^{\circ }\) C). Kuphatikiza apo, waya wa Dynalloy, Inc. Flexinol shape memory alloy unagwiritsidwa ntchito muzoyesera, ndipo zinthu zomwe zimagwirizana ndi waya wa Flexinol zinagwiritsidwa ntchito muzoyeserera. Mawaya angapo a SMA amakonzedwa ngati ulusi womwe ulipo mu dongosolo la minofu ya bimodal kuti apeze mphamvu zazikulu zopangidwa ndi ma actuator a multilayer, monga momwe zasonyezedwera mu Chithunzi 9b, d.
Monga momwe zasonyezedwera pa Chithunzi 9a, ngodya yolunjika yopangidwa ndi waya wa SMA wosunthika imatchedwa ngodya (\(\alpha\)). Ndi ma terminal clamps olumikizidwa ku ma clamps akumanzere ndi akumanja, waya wa SMA umagwira pa ngodya ya bimodal yomwe mukufuna. Chipangizo cha bias spring chomwe chimagwiridwa pa cholumikizira cha spring chimapangidwa kuti chisinthe magulu osiyanasiyana a bias spring extension malinga ndi chiwerengero (n) cha ulusi wa SMA. Kuphatikiza apo, malo a magawo osuntha adapangidwa kuti waya wa SMA awonekere kumalo akunja kuti aziziritse mwamphamvu. Ma plates apamwamba ndi apansi a assembly yochotsedwa amathandizira kuti waya wa SMA uzizire ndi ma cutouts otulutsidwa omwe adapangidwa kuti achepetse kulemera. Kuphatikiza apo, malekezero onse awiri a waya wa CMA amakhazikika kuma terminals akumanzere ndi akumanja, motsatana, pogwiritsa ntchito crimp. Plunger imalumikizidwa kumapeto amodzi a assembly yosunthika kuti isunge malo pakati pa ma plates apamwamba ndi apansi. Plunger imagwiritsidwanso ntchito kugwiritsa ntchito mphamvu yotsekera ku sensa kudzera pa kukhudzana kuti iyeze mphamvu yotsekera pamene waya wa SMA wayamba kugwira ntchito.
Kapangidwe ka minofu ya bimodal SMA kamalumikizidwa motsatizana ndipo kamayendetsedwa ndi magetsi olowera. Panthawi ya voltage pulse cycle, magetsi akagwiritsidwa ntchito ndipo waya wa SMA ukatenthedwa pamwamba pa kutentha koyambirira kwa austenite, kutalika kwa waya mu chingwe chilichonse kumafupikitsidwa. Kubweza kumeneku kumayatsa gawo losunthika la mkono wosunthika. Pamene voltage inayikidwa zero mu cycle yomweyo, waya wa SMA wotenthedwa unazizidwa pansi pa kutentha kwa pamwamba pa martensite, motero kubwerera kumalo ake oyambirira. Pansi pa mikhalidwe ya zero stress, waya wa SMA poyamba umatambasulidwa pang'onopang'ono ndi kasupe wa bias kuti ufike ku mkhalidwe wa martensitic wosweka. Skurufu, yomwe waya wa SMA umadutsa, imayenda chifukwa cha kupsinjika komwe kumachitika poyika voltage pulse ku waya wa SMA (SPA imafika ku gawo la austenite), zomwe zimapangitsa kuti lever yosunthika igwire ntchito. Pamene waya wa SMA wabwezedwa, kasupe wa bias amapanga mphamvu yotsutsana potambasula kasupe. Pamene kupsinjika kwa mphamvu ya impulse voltage kukukhala zero, waya wa SMA umatambasuka ndikusintha mawonekedwe ake chifukwa cha kuzizira kwa convection, kufika pa gawo la martensitic kawiri.
Dongosolo loyendetsera magetsi lochokera ku SMA lomwe likuperekedwa lili ndi mawonekedwe a bimodal momwe mawaya a SMA amakhomeredwa. (a) likuwonetsa chitsanzo cha CAD cha prototype, chomwe chimatchula zina mwa zigawo ndi matanthauzo ake a prototype, (b, d) chikuyimira prototype yoyesera yomwe yapangidwa35. Pomwe (b) ikuwonetsa mawonekedwe apamwamba a prototype yokhala ndi maulumikizidwe amagetsi ndi ma spring a bias ndi ma gauge ogwiritsidwa ntchito, (d) ikuwonetsa mawonekedwe a kukhazikitsa. (e) Chithunzi cha dongosolo loyendetsera magetsi lokhala ndi mawaya a SMA omwe amayikidwa bimodally nthawi iliyonse t, kusonyeza njira ndi njira ya ulusi ndi mphamvu ya minofu. (c) Kulumikizana kwa prismatic kozungulira kwa 2-DOF kwaperekedwa kuti kugwiritsidwe ntchito actuator yochokera ku SMA ya ndege ziwiri. Monga momwe zasonyezedwera, ulalowu umatumiza kuyenda kolunjika kuchokera pansi kupita ku mkono wapamwamba, ndikupanga kulumikizana kozungulira. Kumbali inayi, kuyenda kwa ma prism awiriwa ndikofanana ndi kuyenda kwa multilayer first stage drive.
Kafukufuku woyeserera unachitika pa chitsanzo chomwe chawonetsedwa pa Chithunzi 9b kuti awone momwe galimoto ya bimodal imagwirira ntchito potengera SMA. Monga momwe zasonyezedwera pa Chithunzi 10a, kukhazikitsa koyesererako kunaphatikizapo magetsi a DC omwe angakonzedwe kuti apereke magetsi olowera ku mawaya a SMA. Monga momwe zasonyezedwera pa chithunzi 10b, piezoelectric strain gauge (PACEline CFT/5kN) idagwiritsidwa ntchito poyesa mphamvu yoletsa pogwiritsa ntchito Graphtec GL-2000 data logger. Detayo imalembedwa ndi wolandila kuti aphunzire zambiri. Ma strain gauges ndi ma charge amplifiers amafunika magetsi okhazikika kuti apange chizindikiro cha magetsi. Zizindikiro zofananazo zimasinthidwa kukhala mphamvu zotulutsa malinga ndi kukhudzidwa kwa sensor ya mphamvu ya piezoelectric ndi magawo ena monga momwe tafotokozera mu Table 2. Pamene magetsi agwiritsidwa ntchito, kutentha kwa waya wa SMA kumawonjezeka, zomwe zimapangitsa waya wa SMA kupanikizika, zomwe zimapangitsa kuti actuator ipange mphamvu. Zotsatira zoyesera za kutulutsa mphamvu ya minofu ndi magetsi olowera a 7 V zikuwonetsedwa pa chithunzi 2a.
(a) Dongosolo la actuator lochokera ku SMA linakhazikitsidwa mu kuyeseraku kuti liyese mphamvu yopangidwa ndi actuator. Selo yonyamula imayesa mphamvu yoletsa ndipo imayendetsedwa ndi magetsi a 24 V DC. Kutsika kwa magetsi a 7 V kunagwiritsidwa ntchito kutalika konse kwa chingwe pogwiritsa ntchito magetsi a GW Instek omwe angakonzedwe. Waya wa SMA umachepa chifukwa cha kutentha, ndipo mkono wosunthika umalumikizana ndi selo yonyamula ndipo umakhala ndi mphamvu yoletsa. Selo yonyamula imalumikizidwa ku logger ya data ya GL-2000 ndipo deta imasungidwa pa host kuti ikonzedwenso. (b) Chithunzi chosonyeza unyolo wa zigawo za kuyesera koyesa mphamvu ya minofu.
Ma alloys okumbukira mawonekedwe amasangalatsidwa ndi mphamvu ya kutentha, kotero kutentha kumakhala gawo lofunika kwambiri pophunzira zochitika za kukumbukira mawonekedwe. Mwachiyembekezo, monga momwe zasonyezedwera mu Chithunzi 11a, kujambula kutentha ndi kuyeza kutentha kunachitika pa actuator yochokera ku SMA-based divalerate. Gwero la DC lomwe lingakonzedwe linagwiritsa ntchito magetsi olowera ku mawaya a SMA mu kukhazikitsidwa koyesera, monga momwe zasonyezedwera mu Chithunzi 11b. Kusintha kwa kutentha kwa waya wa SMA kunayesedwa nthawi yeniyeni pogwiritsa ntchito kamera ya LWIR yolimba kwambiri (FLIR A655sc). Wolandila amagwiritsa ntchito pulogalamu ya ResearchIR kulemba deta kuti ikonzedwenso pambuyo pake. Pamene magetsi agwiritsidwa ntchito, kutentha kwa waya wa SMA kumawonjezeka, zomwe zimapangitsa kuti waya wa SMA uchepe. Pa chithunzi. Chithunzi 2b chikuwonetsa zotsatira zoyesera za kutentha kwa waya wa SMA poyerekeza ndi nthawi ya magetsi a 7V input voltage.
Nthawi yotumizira: Sep-28-2022
