RAZVOJ IN VODENJE NAPRAVE ZA URJENJE SPREMINJANJA SMERI HOJE

PAVČIČ, JANEZ (author), Matjačič, Zlatko (mentor)

Osnovni način premikanja človeka po prostoru je hoja. Zaradi poškodb ali bolezni, ki prizadenejo delovanje centralnega in/ali perifernega živčevja, se sposobnost samostojne hoje v velikem številu primerov poslabša. V preteklosti je rehabilitacija oseb s težavami pri hoji potekala predvsem med hojo po tleh pod vodstvom in s podporo izkušenih terapevtov. Z razvojem rehabilitacijske tehnologije, pa se je vadba hoje pričela izvajati tudi na motoriziranih tekočih trakovih, ki omogočajo hojo z velikim številom ponovitev želenih gibov na omejenem prostoru. Uporaba tekočih trakov je v kliničnem okolju postala uveljavljena praksa. Tekoči trakovi so lahko opremljeni tudi z različnimi senzorji, s katerimi lahko merimo način hoje. Tekoči trakovi so lahko sestavni del različnih robotskih sistemov, ki so namenjeni vadbi hoje oziroma cikličnemu gibanju spodnjih udov. Z obstoječimi rehabilitacijskimi napravami se pretežno vadi le hojo naravnost. Kljub napredku na področju rehabilitacijske robotike, še ne obstaja ustrezna naprava, s katero bi lahko vadili hojo, ki vključuje tudi izvajanje zavojev, kar je precejšnja omejitev. Izvajanje zavoja je namreč zahtevnejša naloga od hoje naravnost, zato se pri spreminjanju smeri hoje pri starejši populaciji ter pri osebah s težavami pri hoji večkrat primerijo padci. Da bi zapolnili vrzel, ki obstaja na področju rehabilitacijskih naprav za urjenje hoje, smo razvili novo napravo – vrteči se tekoči trak (VTT), ki omogoča vadbo tako hoje naravnost, kakor tudi urjenje hoje v zavoju. Običajnemu tekočemu traku smo dodali novo prostostno stopnjo – rotacijo v transverzalni ravnini, s katero uporabniku vsiljujemo spremembo smeri hoje. x Disertacija je sestavljena iz dveh vsebinsko zaokroženih sklopov. V prvem delu disertacije je predstavljena študija, s katero smo ugotavljali podobnost med spreminjanjem smeri hoje po tleh in hojo po VTT, ki se je v transverzalni ravnini vrtel s konstantno kotno hitrostjo. Drugi del disertacije opisuje izsledke raziskave, pri kateri smo primerjali dva različna načina vodenja kotne hitrosti tekočega traku. VTT je sestavljen iz treh delov: nepremične podlage, nosilnega ogrodja in običajnega tekočega traku. Na podlago je integrirana nepremična os rotacije, medtem ko nosilno ogrodje, z ustrezno nameščenimi koleščki, omogoča kroženje okoli omenjene osi rotacije in hkrati nosi tekoči trak. Sestavni del naprave je tudi medenična opora, s katero zagotavljamo nastavljivo stopnjo mehanske podpore v višini medenice. Medenična opora preko elastičnih sil, ki delujejo na medenico hodeče osebe, nudi ustrezno podporo pri vzdrževanju dinamičnega ravnotežja, hkrati pa osebi vsiljuje smer tekočega traku, če se le-ta giblje z neko kotno hitrostjo. Medenična opora je obenem tudi varnostni ukrep, ki ob morebitni izgubi dinamičnega ravnotežja uporabnika preprečuje padec. Na medenično oporo sta nameščena dva senzorja naklona, ki dajeta krmilni signal za vodenje VTT. Naprava ima dva načina delovanja: voden ali prost način. Pri vodenem načinu naprava vsiljuje gibanje uporabniku (npr. s spremembo linearne in/ali kotne hitrosti), pri prostem načinu pa je upravljanje linearne ali kotne hitrosti naprave prepuščeno uporabniku. Razvita sta bila dva načina vodenja kotne hitrosti tekočega traku; oba temeljita na gibanju medenice v medenični opori. Pri prvem načinu uporabnik spreminja kotno hitrost naprave s premikanjem medenice v medio-lateralni smeri, pri drugem načinu pa z rotacijo medenice v transverzalni ravnini. Uporabnik naprave preko zaslona spremlja okolje navidezne resničnosti, ki prikazuje animirano pokrajino in se spreminja skladno z gibanjem tekočega traku. S pomočjo okolja navidezne resničnosti uporabnik prejema povratne informacije o uspešnosti vadbe, hkrati pa postane vadba hoje zanimivejša in manj monotona. V sklopu študije o primerljivosti hoje s spreminjanjem smeri po tleh s hojo po VTT smo zasnovali protokol hoje, s katerim smo dosegli podobne pogoje za obe vrsti hoje (po tleh in po VTT). V raziskavi je sodelovala skupina desetih zdravih ljudi, katerim smo med izvajanjem obeh načinov hoje z optičnim sistemom VICON izmerili kinematične in dolžinske parametre hoje. Stopnjo podobnosti kinematičnih parametrov medenice in trupa med obema načinoma hoje smo ocenili z uporabo intraklasne korelacije. Izmerili smo tudi kinematične parametre sklepov spodnjih udov (kolk, koleno, gleženj) med obema načinoma hoje ter izračunali obseg gibov za vsak sklep posebej. Izračunali smo tudi parne t-teste obsegov gibov. xi Zaradi karakterističnih sprememb, ki nastanejo pri hoji po tekočem traku, nismo mogli neposredno primerjati dolžin dvojnih korakov med obema načinoma hoje. Zato smo se osredotočili na razlike, ki nastanejo med levo in desno nogo pri izvajanju zavojev pri izbranem načinu hoje. Statistično pomembnost razlik med dolžinami korakov leve in desne noge smo raziskali z uporabo parnega t-testa. Pri eni osebi smo z uporabo merilnih vložkov za merjenje pritiska izvedli tudi meritev vertikalnih sil pri odrivu med obema načinoma hoje. Primerjali smo odrivne sile iste noge, ko se je le-ta nahajala na notranji ali zunanji strani zavoja (npr. leva noga je zunanja noga pri desnem zavoju, ter notranja noga pri levem zavoju). Rezultati primerjave kinematičnih podatkov medenice in trupa kažejo na visoko stopnjo ujemanja med obema načinoma hoje. Med hojo po tleh smo v primerjavi s hojo po tekočem traku izmerili malenkostno povečan obseg gibov sklepov spodnjih udov. Vendar kljub izvajanju zavojev, nismo zaznali pomembnih razlik med obsegom gibov sklepov notranje in zunanje noge. Rezultati primerjave dolžinskih parametrov pa nakazujejo, da obstaja statistično pomembna razlika med dolžinama korakov leve in desne noge med izvajanjem zavojev pri obeh načinih hoje. Meritve kinetičnih parametrov hoje med izvajanjem zavojev pri obeh načinih hoje so pokazale večje odrivne sile pri zunanji nogi v primerjavi z notranjo nogo. V drugem delu disertacije je opisana študija, s katero smo primerjali dva načina vodenja kotne hitrosti tekočega traku. Namen študije je bil ugotoviti stopnjo podobnosti med kinematičnimi parametri hoje po VTT (pri dveh različnih načinih vodenja) in kinematičnimi parametri spreminjanja smeri hoje po tleh. Z uporabo inercialnih senzorjev za zajem gibanja (Xsens MTx), smo zajeli kinematične parametre stopal, medenice in trupa v transverzalni ravnini. En senzor smo uporabili za merjenje rotacije VTT. V raziskavi je sodelovalo 11 zdravih oseb, vendar podatki dveh oseb niso bili primerni, zato so bili izključeni iz nadaljnje analize. Iz izmerjenih kinematičnih parametrov medenice in trupa lahko opazimo glavno razliko med obema načinoma vodenja: pri vodenju z odmikom medenice v medio-lateralni smeri so kinematični parametri hoje na VTT podobni kinematičnim parametrom hoje v smeri naravnost, medtem ko se pri vodenju z rotacijo medenice opazi povečan zasuk celotnega telesa v smeri zavoja. Primerjali smo tudi relativno gibanje medenice in trupa v transverzalni ravnini med obema načinoma vodenja VTT in hojo po tleh. Za ocenjevanje stopnje podobnosti relativnega gibanja medenice in trupa smo uporabili intraklasno korelacijo. Dobljene vrednosti kažejo, da oba uporabljena načina vodenja VTT izkazujeta približno enako stopnjo podobnosti s kinematičnimi podatki hoje po tleh. xii Rezultati prve študije nakazujejo, da obstaja podobnost med kinematičnimi meritvami pri izvajanju zavojev po tleh in hojo po vrtečem se tekočem traku. Ugotovili smo tudi, da se med izvajanjem zavojev pri obeh načinih hoje pojavi razlika med dolžinama dvojnega koraka leve in desne noge. Meritve sil odriva nakazujejo podobne mehanizme izvajanja zavoja tako na VTT kot tudi med hojo v zavoju po tleh. Iz rezultatov druge študije lahko sklepamo, da sta oba načina vodenja kotne hitrosti enakovredna, tako da je izbira načina vodenja kotne hitrosti VTT lahko prepuščena izbiri posameznemu uporabniku oziroma terapevtu. Na podlagi teh rezultatov lahko zaključimo, da je hoja v zavoju po VTT zelo podobna hoji v zavoju po tleh, kar nakazuje na uporabnost VTT za urjenje spreminjanja smeri med hojo oseb z nevrološkimi okvarami.

• Language: Slovenian
• Keywords: vrteči se tekoči trak, kinematični parametri med spreminjanjem smeri hoje, vodenje kotne hitrosti tekočega traku, rehabilitacijska robotika
• Work type: Doctoral dissertation
• Organization: FE - Faculty of Electrical Engineering
• Year: 2015
• PID: 20.500.12556/RUL-30810
• COBISS.SI-ID: 11038804
• Publication date in RUL: 29.05.2015

Secondary language

• Language: English
• Title: DEVELOPMENT AND CONTROL OF AN APPARATUS FOR PRACTICING OF TURNING MANEUVERS DURING WALKING

Abstract

Walking is an elementary way of human movement. However, ability to walk independently can deteriorate due to injury or disease, which affects central and/or peripheral nervous system. In the past gait rehabilitation was conducted predominantly during overground walking under the supervision of experienced therapists. With progress in rehabilitation technology, it was made possible to use a motorized treadmill during gait training. Treadmill allows many repetitions of desired walking motion, which are performed in a limited space. Treadmills can be incorporated into different robotic systems designed to perform cyclic movement of lower extremities. Despite of the progress, made in the field of rehabilitation robotics, contemporary rehabilitation devices only support walking in the forward direction and omit training of turning. Walking with turning is more demanding when compared to straight walking and can result in falling, especially in people with walking difficulties or elderly population. To overcome previously mentioned gap in rehabilitation robotics we developed a device – rotating treadmill (RT), which allows training of forward walking and training of turning. We modified a conventional treadmill, by introducing a new degree of freedom that enables rotation of the entire treadmill in transversal plane, which is meant to impose a change of walking direction to the treadmill user. This dissertation consists of two parts. In the first part we present a study that investigated the degree of similarity between overground turning and turning when walking on the RT rotating with constant angular velocity in the transversal plane. In the second part xiv of the dissertation we present findings of a study where we compared two different methods of controlling the rotation of RT around the vertical axis. Rotating treadmill is composed of three main components: base plate, bearing rotating platform and conventional treadmill. Base plate provides axis of rotation, while rotating platform, through properly mounted wheels, enables circular motion of the treadmill around the vertical axis. RT has integrated pelvic support mechanism through which we can adjust the level of passive mechanical support at pelvis height. Pelvic support helps maintaining dynamic stability of the user through adjustable magnitude of elastic forces that act on the pelvis. It also represents a safety feature for fall prevention. Two inclination sensors are attached to the pelvic support mechanism, which are used to control linear and/or angular velocity of RT. There are two modes of RT operation: guided mode and free mode. In guided mode the RT imposes a movement to the user (i.e. with a change in linear and/or angular velocity), whereas in the free mode user controls linear and angular velocity of the treadmill. We developed two methods of angular velocity control which are based on pelvis movement. User changes angular velocity of RT through movement of pelvis in medio-lateral direction, when using the first method of control, and rotation of the pelvis in transversal plane when using second method of control. User can observe animated landscape rendered in virtual reality application which changes in accordance with movement of RT via monitor. With the use of virtual environment user receives performance feedback while at the same time training becomes more interesting. Within the study of comparability of overground turning and turning with RT we conceived a protocol of walking which ensures similar conditions for both experimental conditions of walking (i.e. walking overground and walking on the RT). Ten healthy subjects participated in the study. During both experimental conditions of walking we used optical measurement system (Vicon) to measure kinematic and spatial parameters. Degree of similarity of pelvic and torso kinematic was assessed using intraclass correlation coefficient method. We also measured kinematics of lower extremities joints (hip, knee, and ankle) during both experimental conditions of walking and we also calculated range of motion for each joint. We used paired t-test to compare statistical differences in range of motion in particular joints. Due to characteristic changes, which occur while walking on a treadmill, we could not directly compare the calculated stride lengths between both experimental conditions of walking. For that reason we chose to observe differences between left and right stride lengths during each experimental condition of walking separately. Statistically significant xv differences in stride lengths were confirmed using paired t-test. In the case of one participant we also measured push-off forces using insole pressure sensor. We compared push-off forces of the same leg, when it was performing push-off as a inner and as an outer leg, during turning for both experimental conditions of walking (i.e. left leg acts as the outer leg during turning to the right, and as the inner leg during turning to the left). Comparison of pelvis and torso kinematics indicates a high degree of similarity between both experimental conditions of walking. There was slight increase in the range of motion of lower extremities joints during overground walking as compared to treadmill walking. Despite performing turning manoeuvres we did not observe relevant differences in range of motion between joints of inner and outer leg. Results of stride lengths indicate statistically significant difference between left and right leg during turning for both experimental conditions of walking. Kinetic results of turning showed increased push-off forces in the outer leg when compared to the inner leg during turning for both experimental conditions of walking. In the second part of dissertation we present a study in which we compared two different methods of angular velocity control. The goal of the study was to examine which method of angular velocity control yields kinematic, which is similar to kinematic of overground turning. Kinematic data of feet, pelvis and torso in the transversal plane was captured with inertial sensors (Xsens MTx). One sensor was used to measure the rotation of RT around the vertical axis. Eleven healthy subjects participated in this study, however the data of two subjects were not usable for further analysis. From kinematic data of pelvis and torso we can observe main differences between both methods of angular velocity control: kinematics of turning with displacement of pelvis in medio-lateral direction yields kinematics similar to the one observed in the straight walking, while on the other hand we can observe increased rotation of whole body to the direction of turning when subject is using the second method of angular velocity control (i.e. pelvic rotation in transversal plane). We also compared relative motion of pelvis and torso for both control approaches to detect possible similarities with overground walking. To establish degree of similarity between both approaches of controlling the angular velocity and overground turning, we calculated intraclass correlation coefficients of relative pelvis and torso motion. Results indicate similarity of kinematics between the two control methods. Results of the first study indicate similarity in kinematics between overground turning and turning walking on the rotating treadmill. We have also shown that there is a difference in stride lengths between left and right leg during turning when walking in both experimental xvi conditions. Kinetic data indicate the use of similar mechanisms of turning during overground and treadmill walking. Results of second study imply that the two methods of controlling treadmill’s angular velocity are equivalent. On the basis of obtained results we can conclude that walking while turning during overground walking is similar to turning when walking on the developed rotating treadmill. That indicates the possibility of using RT in training of turning manoeuvres during rehabilitation of walking in neurologically impaired individuals.

• Keywords: rotating treadmill, kinematics of turning, treadmill angular velocity control, rehabilitation robotics