Kuchokera ku unyolo wa robotic drive mpaka ma conveyor lamba mu ntchito za supply chain mpaka kusuntha kwa nsanja za wind turbine, position sensing ndi ntchito yofunika kwambiri pa ntchito zosiyanasiyana. Imatha kukhala ndi mitundu yosiyanasiyana, kuphatikizapo linear, rotary, angular, absolute, incremental, contact ndi non-contact sensors. Masensa apadera apangidwa omwe amatha kudziwa malo m'magawo atatu. Ukadaulo wodziwa malo umaphatikizapo potentiometric, inductive, eddy current, capacitive, magnetostrictive, Hall effect, fiber optic, optical ndi ultrasonic.
Mafunso Ofunsidwa Kawirikawiri awa akupereka chiyambi chachidule cha mitundu yosiyanasiyana ya kuzindikira malo, kenako akuwunikanso ukadaulo wosiyanasiyana womwe opanga angasankhe pokhazikitsa njira yodziwira malo.
Ma sensor a Potentiometric ndi zida zochokera ku resistance zomwe zimaphatikiza njira yokhazikika yotsutsa ndi chotsukira chomwe chimalumikizidwa ku chinthu chomwe malo ake amafunika kumvedwa. Kusuntha kwa chinthucho kumasuntha ma wipers m'njira. Malo a chinthucho amayesedwa pogwiritsa ntchito netiweki yogawa magetsi yopangidwa ndi ma rails ndi ma wipers kuti ayesere kuyenda kolunjika kapena kozungulira ndi DC voltage yokhazikika (Chithunzi 1). Ma sensor a Potentiometric ndi otsika mtengo, koma nthawi zambiri amakhala ndi kulondola kochepa komanso kubwerezabwereza.
Ma sensor a malo oyendetsera ntchito amagwiritsa ntchito kusintha kwa mphamvu ya maginito yomwe imayambitsidwa mu coil ya sensor. Kutengera ndi kapangidwe kake, amatha kuyeza malo ozungulira kapena ozungulira. Ma sensor a malo a Linear Variable Differential Transformer (LVDT) amagwiritsa ntchito ma coil atatu ozunguliridwa mozungulira chubu chopanda kanthu; coil yoyamba ndi ma coil awiri achiwiri. Ma coil amalumikizidwa motsatizana, ndipo ubale wa gawo la coil yachiwiri ndi 180° kunja kwa gawo poyerekeza ndi coil yoyamba. Pakati pa ferromagnetic yotchedwa armature imayikidwa mkati mwa chubu ndikulumikizidwa ku chinthu chomwe chili pamalo omwe akuyesedwa. Voliyumu yosonkhezera imagwiritsidwa ntchito pa coil yoyamba ndipo mphamvu yamagetsi (EMF) imayambitsidwa mu coil yachiwiri. Poyesa kusiyana kwa voltage pakati pa ma coil achiwiri, malo ogwirizana a armature ndi zomwe zimamangiriridwako zitha kudziwika. Transformer yosinthasintha ya voltage yozungulira (RVDT) imagwiritsa ntchito njira yomweyo kutsatira malo ozungulira. Ma sensor a LVDT ndi RVDT amapereka kulondola kwabwino, kulumikizana, kutsimikiza komanso kukhudzidwa kwakukulu. Sali ndi kukangana ndipo amatha kutsekedwa kuti agwiritsidwe ntchito m'malo ovuta.
Ma sensor a Eddy current position amagwira ntchito ndi zinthu zoyendetsera magetsi. Mafunde a Eddy ndi mafunde omwe amapezeka muzinthu zoyendetsera magetsi pomwe pali mphamvu ya maginito yosintha. Mafunde awa amayenda mozungulira mozungulira ndikupanga mphamvu ya maginito yachiwiri. Ma sensor a Eddy current amakhala ndi ma coil ndi ma linearization circuits. Mphamvu yosinthira imalimbikitsa coil kuti ipange mphamvu ya maginito yoyamba. Chinthu chikayandikira kapena kuchoka pa coil, malo ake amatha kumveka pogwiritsa ntchito kuyanjana kwa mphamvu yamagetsi yachiwiri yomwe imapangidwa ndi ma eddy currents, zomwe zimakhudza impedance ya coil. Pamene chinthucho chikuyandikira coil, kutayika kwa mphamvu yamagetsi ya eddy kumawonjezeka ndipo mphamvu yamagetsi ya oscillating imakhala yochepa (Chithunzi 2). Mphamvu yamagetsi ya oscillating imakonzedwa ndikukonzedwa ndi dera la linearizer kuti ipange mphamvu ya DC yolingana ndi mtunda wa chinthucho.
Zipangizo zamagetsi za Eddy ndi zida zolimba, zosakhudzana ndi chinthu chomwe nthawi zambiri chimagwiritsidwa ntchito ngati masensa oyandikira. Zili ndi mbali zonse ndipo zimatha kudziwa mtunda woyerekeza ndi chinthucho, koma osati komwe chikupita kapena mtunda wokwanira kupita ku chinthucho.
Monga momwe dzinalo likusonyezera, masensa okhala ndi malo ogwirira ntchito amayesa kusintha kwa mphamvu kuti adziwe malo a chinthu chomwe chikumveka. Masensa osalumikizana awa angagwiritsidwe ntchito kuyeza malo olunjika kapena ozungulira. Amapangidwa ndi mbale ziwiri zolekanitsidwa ndi zinthu zamagetsi ndipo amagwiritsa ntchito njira imodzi mwa ziwiri kuti azindikire malo a chinthu:
Pofuna kusintha kwa chokhazikika cha dielectric, chinthu chomwe malo ake ayenera kuzindikirika chimalumikizidwa ndi zinthu za dielectric. Pamene zinthu za dielectric zikuyenda, chokhazikika cha dielectric chogwira ntchito cha capacitor chimasintha chifukwa cha kuphatikiza kwa dera la zinthu za dielectric ndi chokhazikika cha dielectric cha mpweya. Kapenanso, chinthucho chikhoza kulumikizidwa ku imodzi mwa mbale za capacitor. Pamene chinthucho chikuyenda, mbalezo zimayandikira kapena kupitirira, ndipo kusintha kwa capacitance kumagwiritsidwa ntchito kudziwa malo ogwirizana.
Masensa otha kusuntha amatha kuyeza kusuntha, mtunda, malo ndi makulidwe a zinthu. Chifukwa cha kukhazikika kwawo kwakukulu kwa chizindikiro ndi kukana, masensa otha kusuntha amagwiritsidwa ntchito m'malo ochitira labotale ndi mafakitale. Mwachitsanzo, masensa otha kusuntha amagwiritsidwa ntchito kuyeza makulidwe a filimu ndi zomatira zomwe zimagwiritsidwa ntchito zokha. Mu makina a mafakitale, amagwiritsidwa ntchito kuyang'anira kusuntha ndi malo a zida.
Magnetostriction ndi chinthu chomwe chimapangitsa kuti zinthuzo zisinthe kukula kapena mawonekedwe ake pamene mphamvu ya maginito ikugwiritsidwa ntchito. Mu sensa ya malo oletsa maginito, maginito osunthika amamangiriridwa ku chinthu chomwe chikuyesedwa. Chimakhala ndi waveguide yokhala ndi mawaya omwe amanyamula ma current pulses, olumikizidwa ku sensa yomwe ili kumapeto kwa waveguide (Chithunzi 3). Pamene current pulse imatumizidwa pansi pa waveguide, mphamvu ya maginito imapangidwa mu waya yomwe imalumikizana ndi axial magnetic field ya maginito okhazikika (maginito omwe ali mu silinda piston, Chithunzi 3a). Kuyanjana kwa munda kumachitika chifukwa cha kupotoza (Wiedemann effect), komwe kumakhudza waya, ndikupanga acoustic pulse yomwe imafalikira motsatira waveguide ndipo imadziwika ndi sensa kumapeto kwa waveguide (Chithunzi 3b). Poyesa nthawi yodutsa pakati pa kuyamba kwa current pulse ndi kuzindikira acoustic pulse, malo ogwirizana a maginito omwe ali ndi chifukwa chake chinthucho chikhoza kuyezedwa (Chithunzi 3c).
Masensa oletsa kukhudzana ndi maginito ndi masensa osakhudzana omwe amagwiritsidwa ntchito kuzindikira malo olunjika. Ma waveguides nthawi zambiri amakhala m'machubu achitsulo chosapanga dzimbiri kapena aluminiyamu, zomwe zimathandiza masensawa kugwiritsidwa ntchito m'malo odetsedwa kapena onyowa.
Pamene kondakitala yopyapyala, yathyathyathya ikayikidwa mu mphamvu ya maginito, mphamvu iliyonse yoyenda imasonkhana mbali imodzi ya kondakitala, zomwe zimapangitsa kusiyana komwe kungatchulidwe kuti mphamvu ya Hall. Ngati mphamvu yamagetsi mu kondakitala ndi yosasintha, kukula kwa mphamvu ya Hall kudzawonetsa mphamvu ya mphamvu ya maginito. Mu sensa ya Hall-effect position, chinthucho chimalumikizidwa ndi maginito yomwe ili mu shaft ya sensa. Pamene chinthucho chikuyenda, malo a maginito amasintha poyerekeza ndi chinthu cha Hall, zomwe zimapangitsa kuti mphamvu ya Hall isinthe. Poyesa mphamvu ya Hall, malo a chinthu amatha kudziwika. Pali masensa apadera a Hall-effect position omwe amatha kudziwa malo m'magawo atatu (Chithunzi 4). Masensa a Hall-effect position ndi zida zosakhudzana zomwe zimapereka kudalirika kwakukulu komanso kuzindikira mwachangu, ndipo zimagwira ntchito pa kutentha kwakukulu. Amagwiritsidwa ntchito m'magwiritsidwe osiyanasiyana a ogula, mafakitale, magalimoto ndi azachipatala.
Pali mitundu iwiri yoyambira ya masensa a fiber optic. Mu masensa a fiber optic amkati, ulusi umagwiritsidwa ntchito ngati chinthu chowunikira. Mu masensa akunja a fiber optic, fiber optics amaphatikizidwa ndi ukadaulo wina wa sensor kuti atumize chizindikiro ku zamagetsi akutali kuti chigwiritsidwe ntchito. Pankhani yoyezera malo a ulusi wamkati, chipangizo monga chowunikira nthawi ya domain reflectometer chingagwiritsidwe ntchito kudziwa kuchedwa kwa nthawi. Kusintha kwa kutalika kwa nthawi kumatha kuwerengedwa pogwiritsa ntchito chida chomwe chimagwiritsa ntchito chowunikira ma frequency domain reflectometer. Masensa a fiber optic sakhudzidwa ndi kusokonezedwa kwa ma electromagnetic, amatha kupangidwa kuti azigwira ntchito kutentha kwambiri, ndipo sagwira ntchito, kotero amatha kugwiritsidwa ntchito pafupi ndi zinthu zotentha kwambiri kapena zoyaka.
Kuzindikira kwina kwa fiber-optic kochokera ku ukadaulo wa fiber Bragg grating (FBG) kungagwiritsidwenso ntchito poyesa malo. FBG imagwira ntchito ngati fyuluta yowunikira, kuwonetsa gawo laling'ono la kuwala komwe kuli pakati pa Bragg wavelength (λB) ikawunikiridwa ndi kuwala kwa broad-spectrum. Imapangidwa ndi ma microstructures ojambulidwa mkati mwa fiber core. FBGs ingagwiritsidwe ntchito poyesa magawo osiyanasiyana monga kutentha, kupsinjika, kupanikizika, kupendekeka, kusamuka, kufulumira ndi katundu.
Pali mitundu iwiri ya masensa owonera malo, omwe amadziwikanso kuti ma optical encoders. Mu nkhani imodzi, kuwala kumatumizidwa kwa wolandila mbali ina ya sensa. Mu mtundu wachiwiri, chizindikiro cha kuwala chomwe chimatulutsa chimawonetsedwa ndi chinthu choyang'aniridwa ndikubwerera ku gwero la kuwala. Kutengera kapangidwe ka sensa, kusintha kwa mawonekedwe a kuwala, monga kutalika kwa nthawi, mphamvu, gawo kapena polarization, zimagwiritsidwa ntchito kudziwa malo a chinthu. Masensa owonera malo opangidwa ndi encoder amapezeka kuti azitha kuyenda molunjika komanso mozungulira. Masensa awa amagawidwa m'magulu atatu akuluakulu; ma transmissive optical encoders, reflective optical encoders, ndi interferometric optical encoders.
Ma sensor a malo opangidwa ndi ultrasonic amagwiritsa ntchito ma transducer a crystal a piezoelectric kuti atulutse mafunde a ultrasound omwe amathamanga kwambiri. Sensa imayesa phokoso lowonetsedwa. Ma sensor a ultrasonic angagwiritsidwe ntchito ngati ma sensor osavuta apafupi, kapena mapangidwe ovuta kwambiri angapereke chidziwitso chosiyanasiyana. Ma sensor a malo opangidwa ndi ultrasonic amagwira ntchito ndi zinthu zomwe zili ndi zinthu zosiyanasiyana komanso mawonekedwe apamwamba, ndipo amatha kuzindikira zinthu zazing'ono patali kwambiri kuposa mitundu ina yambiri ya ma sensor a malo. Amalimbana ndi kugwedezeka, phokoso lozungulira, kuwala kwa infrared ndi kusokonezeka kwa ma electromagnetic. Zitsanzo za ntchito zomwe zimagwiritsidwa ntchito ndi ma sensor a malo opangidwa ndi ultrasonic zimaphatikizapo kuzindikira mulingo wamadzimadzi, kuwerengera zinthu mwachangu, makina oyendera maloboti, ndi kuzindikira magalimoto. Sensa yachizolowezi ya ultrasonic yamagalimoto imakhala ndi nyumba yapulasitiki, transducer ya piezoelectric yokhala ndi nembanemba yowonjezera, ndi bolodi losindikizidwa lokhala ndi ma electronic circuits ndi ma microcontrollers otumizira, kulandira, ndi kukonza zizindikiro (Chithunzi 5).
Masensa a malo amatha kuyeza mayendedwe athunthu kapena ofanana a mzere, ozungulira komanso a angular a zinthu. Masensa a malo amatha kuyeza mayendedwe a zipangizo monga ma actuator kapena ma motors. Amagwiritsidwanso ntchito m'mapulatifomu oyenda monga ma robot ndi magalimoto. Maukadaulo osiyanasiyana amagwiritsidwa ntchito m'masensa a malo omwe ali ndi mitundu yosiyanasiyana ya kulimba kwa chilengedwe, mtengo, kulondola, kubwerezabwereza, ndi zina.
Masensa a 3D Magnetic Position, Allegro MicrosystemsKusanthula ndi Kukulitsa Chitetezo cha Ma Ultrasonic Sensors a Magalimoto Odziyimira Pawokha, IEEE Internet of Things Journal Momwe mungasankhire sensa ya malo, Cambridge Integrated Circuits Mitundu ya masensa a malo, Ixthus InstrumentationKodi sensa ya malo oyendetsera ndi chiyani?, Keyence Kodi Magnetostrictive Position Sensing ndi Chiyani?, AMETEK
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