Design of a self-leveling cam mechanism for a stair climbing wheelchair

This paper presents a new version of Wheelchair.q, a wheelchair with stair climbing ability. The wheelchair is able to climb single obstacles or staircases thanks to a hybrid wheel-leg locomotion unit with a triple-wheels cluster architecture. The new concept presented in this work represents an improvement respect to previous versions. Through a different arrangement of functional elements, the wheelchair performances in terms of stability and regularity during movement on stair have been increased. In particular, attention has been paid to ensure a regular and comfortable motion for the user during stair climbing operation. For this reason, a cam mechanism has been introduced and designed with the aim to compensate the oscillation generated on the wheelchair frame by the locomotion unit rotation. A design methodology for the cam profile is presented. Moreover, a parametric analysis on the cam profile and on the mechanism dimensions has been conducted with the aim to find a cam profile with suitable dimensions and performances in terms of pressure angle and radius of curvature

Carrozzina elettrica innovativa per il superamento delle barriere architettoniche

La presenza di barriere architettoniche in ambienti pubblici o privati rappresenta una forte limitazione per la mobilità di persone che utilizzano una carrozzina per gli spostamenti quotidiani. Nonostante l’introduzione di normative con lo scopo di promuovere l’abbattimento di queste barriere, non sempre la loro completa eliminazione è realizzata o realizzabile. In queste situazioni è necessario poter fornire all’utente disabile un ausilio in grado di superare autonomamente barriere architettoniche od ostacoli. Tale dispositivo dovrebbe poter essere utilizzato in autonomia, essere trasportabile ed integrato nella struttura della carrozzina, in maniera da essere attivabile all’occorrenza. L’obiettivo di questo lavoro di tesi è quindi l’ideazione di una carrozzina montascale che integri in un unico oggetto le abilità e le funzionalità di una tradizionale carrozzina elettrica e di un montascale. Attualmente, vista le complessità dell’obiettivo, esistono pochi dispositivi di questo tipo disponibili in commercio, mentre un numero più ampio di soluzioni è stato individuato nello stato dell’arte delle ricerche e dei brevetti. In ogni caso le soluzioni individuate presentano forti limitazioni per la diffusione della tecnologia, in quanto in generale risultano ingombranti, complesse, costose e non sembrano rispondere a criteri di accettabilità personale dell’utente. Per questi motivi la tesi di dottorato è stata indirizzata allo sviluppo di un’idea innovativa di carrozzina montascale, con l’obiettivo di ottenere prestazioni superiori rispetto alle soluzioni presentate nello stato dell’arte. In particolare, si è progettato un dispositivo in grado di superare con sicurezza e regolarità rampe di scale e singoli scalini, limitando però allo stesso tempo il peso, l’ingombro e la complessità del veicolo. Particolare attenzione è stata inoltre posta nel garantire un moto su scala con minime oscillazioni percepite dall’utente e nell’ottenere un dispositivo gradevole oltre che funzionale. Caratteristica principale della carrozzina è l’architettura ibrida del sistema di locomozione, composto da una coppia di unità di locomozione motorizzate poste anteriormente e da un cingolo non motorizzato né frenato che costituisce il punto di appoggio posteriore. Le unità di locomozione a zampe rotanti sono costituite da un telaio con tre bracci, ciascuno dei quali porta una ruota all’estremità. Le tre ruote sono ulteriormente collegate tra loro attraverso un rotismo epicicloidale interno all’unità. Questa architettura permette di gestire in maniera semplice e funzionale sia la marcia in piano che la marcia su scale, permettendo inoltre un’agevole transizione tra le due condizioni di impiego. Nel lavoro di tesi proposto verrà analizzata la progettazione cinematica e dinamica del dispositivo, analizzandone il comportamento e le prestazioni di funzionamento. I risultati ottenuti dimostrano l’efficacia della carrozzina proposta nel superare ostacoli in maniera sicura, regolare, adeguata agli obiettivi di progetto richiesti e in grado di rispondere ai requisiti di sicurezza imposti dalla normativa (ad esempio ISO 7176-28:2012, “Requirements and test methods for stair-climbing devices”). La soluzione proposta risulta quindi idonea per essere ulteriormente sviluppata attraverso la realizzazione di un prototipo in grado di validare attraverso una campagna di prove sperimentali l’efficacia dell’architettura di carrozzina montascale descritta in questo lavoro di tesi

Evolution of Wheelchair.q, a Stair-climbing Wheelchair

This paper presents a solution for a stair-climbing wheelchair that can climb single steps or entire staircases. This device was designed in order to ensure greater autonomy for people with reduced mobility . The main component of the wheelchair structure is a three-wheel locomotion unit that allows obstacle climbing thanks to an epicycloidal transmission. The other characteristic element is an idle track that behaves like a second foothold giving static stability during stair-climbing. Another important feature concerned with this design is a reconfiguration mechanism that makes the wheelchair suitable both for stair-climbing and for moving on flat ground. This feature allows performances and overall dimensions comparable to traditional electric wheelchairs. The choice and design of the mechanisms for the reconfiguration phase are the main topics discussed in this article and represent the principal innovations of this wheelchair compared to earlier versions

Graphene Oxide Promotes Site-Selective Allylic Alkylation of Thiophenes with Alcohols

The graphene oxide (GO) assisted allylic alkylation of thiophenes with alcohols is presented. Mild reaction conditions and a low GO loading enabled the isolation of a range of densely functionalized thienyl and bithienyl compounds in moderate to high yields (up to 90%). The cooperative action of the Bronsted acidity, epoxide moieties, and pi-surface of the 2D-promoter is highlighted as crucial in the reaction course of the present Friedel-Crafts-type protocol

Anxiety and depression in keratotic oral lichen planus: a multicentric study from the SIPMO

Objectives: Oral lichen planus with exclusive keratotic reticular, papular, and/or plaque-like lesions (K-OLP) is a clinical pattern of OLP that may be associated with a complex symptomatology and psychological alteration. The aim of the study was to evaluate the prevalence of anxiety (A) and depression (D) in patients with K-OLP, analyzing the potential predictors which can affect mental health status. Methods: Three hundred K-OLP patients versus 300 healthy controls (HC) were recruited in 15 Italian universities. The Numeric Rating Scale (NRS), Total Pain Rating Index (T-PRI), and Hamilton Rating Scales for Depression and for Anxiety (HAM-D and HAM-A) were administered. Results: The K-OLP patients showed statistically higher scores in the NRS, T-PRI, HAM-D, and HAM-A compared with the HC (p-value < 0.001**). A and D were found in 158 (52.7%) and 148 (49.3%) K-OLP patients. Strong linear correlations were identified between HAM-A, HAM-D, NRS, T-PRI, and employment status and between HAM-D, HAM-A, NRS, T-PRI, employment status, and female gender. Multivariate logistic regression revealed that HAM-D and HAM-A showed the greatest increase in the R2 value for A and D in the K-OLP patients, respectively (DR2 = 55.5% p-value < 0.001**; DR2 = 56.5% p-value < 0.001**). Conclusions: The prevalence of A and D is higher in the K-OLP patients compared with the HC, also found in K-OLP subjects without pain, suggesting that the processing of pain may be in a certain way independent of the processing of mood. Clinical relevance: Mood disorders and pain assessment should be carefully performed in relation to K-OLP to obtain a complete analysis of the patients

High Risk of Secondary Infections Following Thrombotic Complications in Patients With COVID-19

Background. This study’s primary aim was to evaluate the impact of thrombotic complications on the development of secondary infections. The secondary aim was to compare the etiology of secondary infections in patients with and without thrombotic complications. Methods. This was a cohort study (NCT04318366) of coronavirus disease 2019 (COVID-19) patients hospitalized at IRCCS San Raffaele Hospital between February 25 and June 30, 2020. Incidence rates (IRs) were calculated by univariable Poisson regression as the number of cases per 1000 person-days of follow-up (PDFU) with 95% confidence intervals. The cumulative incidence functions of secondary infections according to thrombotic complications were compared with Gray’s method accounting for competing risk of death. A multivariable Fine-Gray model was applied to assess factors associated with risk of secondary infections. Results. Overall, 109/904 patients had 176 secondary infections (IR, 10.0; 95% CI, 8.8–11.5; per 1000-PDFU). The IRs of secondary infections among patients with or without thrombotic complications were 15.0 (95% CI, 10.7–21.0) and 9.3 (95% CI, 7.9–11.0) per 1000-PDFU, respectively (P = .017). At multivariable analysis, thrombotic complications were associated with the development of secondary infections (subdistribution hazard ratio, 1.788; 95% CI, 1.018–3.140; P = .043). The etiology of secondary infections was similar in patients with and without thrombotic complications. Conclusions. In patients with COVID-19, thrombotic complications were associated with a high risk of secondary infections

Design and construction of a new version of the Epi.q UGV for monitoring and surveillance tasks

The paper presents a new member of Epi.q robot family, a series of mobile robots with a wheel-legged locomotion and with the ability to overcome obstacles and move on uneven terrains. The particular feature of this robot family is the ability to switch from a wheel locomotion to a leg locomotion without any external active control but only depending on the dynamic conditions. In particular this work deals with the design of the latest prototype developed, analyzing the design and construction phases. This prototype is more powerful than the previous thanks to the possibility to have four driving units instead of two. The robot architecture has been studied in order to be modular. Several robot configurations can be obtained with the same structure and this allows to test how each component affect the overall robot behavior. Moreover the mechanical design is more accurate and reliable respect to previous versions. A sensing system has been introduced with the aim to evaluate the performances of each robot architecture. Finally an on-board processor has been added. This allows the definition of more complex control logics such as the cooperation between a speed control with a torque control in the four driving units configuration. Moreover it increases the smart tasks that the robot is able to perform such as the developing of a remote autonomous control rather than a manual drive by an operator

Análisis cinemático de una silla de ruedas eléctrica escaladora

Introduction: This paper presents the functional designand kinematic synthesis of a recent version of an electricstair-climbing wheelchair. Wheelchair.q: The proposeddevice represents the latest evolution of the ‘Wheelchair.q’project and introduces several improvements over previousdesigns. This updated solution has greater stability duringstair-climbing operation, and it satisfies the safety requirementsintroduced by ISO 7176-28:2012, “Requirementsand test methods for stair-climbing devices”. The mainimprovement presented concerns the regularity of the usertrajectory during stair-climbing, which ensures a morecomfortable perception. This result has been achievedby introducing a cam mechanism between the frameconnected to the locomotion unit and the seat frame,which properly manages the seat orientation. With anappropriate cam profile, it is possible to compensate for theoscillations that are introduced on the wheelchair duringthe climbing sequence and allow the user to obtain atranslational trajectory. Results: The proposed designand its working principle are first described and illustratedthrough schematic and graphic representations. A briefexplanation of the procedure for obtaining the cam profileis also given. Two different architectures for the cammechanism are then compared, and the advantages anddisadvantages for each solution are identified. Finally, thekinematic wheelchair performances are tested through asimulation conducted in the MSC-ADAMS multibodyenvironment. Conclusions: The results obtained with thesimulation show the effectiveness of the proposed solution.The wheelchair is able to climb a staircase in a safe andregular way. Following studies will complete the designof the wheelchair with the aim to build a prototype fordemonstrating the proposed working principle.Introducción: En este trabajo se analiza el comportamientode una silla de ruedas eléctrica para subir escaleras desdeun punto de vista cinemático. Wheelchair.q: El dispositivopropuesto representa la última evolución del proyecto‘Wheelchair.q’ e introduce varias mejoras con respecto a losdiseños anteriores. Esta solución actualizada cuenta conuna mayor estabilidad durante la subida de las escaleras,permitiendo llevar a cabo la tarea de una manera segura,cumpliendo la norma ISO 7176-28:2012. Sin embargo,las principales mejoras atañen a la regularidad de la trayectoriadel usuario durante la subida de escaleras, lo cualpermite obtener una percepción de comodidad mayor.Este resultado se ha logrado mediante la introducciónde un mecanismo de leva que gestiona adecuadamentela orientación del asiento en lo que se refiere al bastidorde la silla de ruedas. Con un perfil de leva apropiado, esposible compensar la oscilación introducida en la silla deruedas durante la secuencia de escalada, para que el usuariopueda obtener una trayectoria de traslación. Resultados:El diseño propuesto y su principio de funcionamiento sedescriben e ilustran en primer lugar a través de representacionesesquemáticas y gráficas, con una breve explicaciónsobre los procedimientos para obtener el perfil de leva. Acontinuación, se comparan las dos diferentes arquitecturasdel mecanismo de leva y se identifican las ventajas ydesventajas de cada solución. Por último, se prueban lasprestaciones de la silla de ruedas cinemática a través de unsimulacro en el ambiente de simulación MSC-ADAMS.Conclusiones: Los resultados obtenidos con la simulaciónmuestran la efectividad de la solución propuesta.La silla de ruedas es capaz de subir una escalera de formasegura y regular. Los siguientes estudios completarán eldiseño de la silla de ruedas con el objetivo de construir unprototipo para demostrar el principio de trabajo propuesto

Análisis cinemático de una silla de ruedas eléctrica escaladora

Introduction: This paper presents the functional designand kinematic synthesis of a recent version of an electricstair-climbing wheelchair. Wheelchair.q: The proposeddevice represents the latest evolution of the ‘Wheelchair.q’project and introduces several improvements over previousdesigns. This updated solution has greater stability duringstair-climbing operation, and it satisfies the safety requirementsintroduced by ISO 7176-28:2012, “Requirementsand test methods for stair-climbing devices”. The mainimprovement presented concerns the regularity of the usertrajectory during stair-climbing, which ensures a morecomfortable perception. This result has been achievedby introducing a cam mechanism between the frameconnected to the locomotion unit and the seat frame,which properly manages the seat orientation. With anappropriate cam profile, it is possible to compensate for theoscillations that are introduced on the wheelchair duringthe climbing sequence and allow the user to obtain atranslational trajectory. Results: The proposed designand its working principle are first described and illustratedthrough schematic and graphic representations. A briefexplanation of the procedure for obtaining the cam profileis also given. Two different architectures for the cammechanism are then compared, and the advantages anddisadvantages for each solution are identified. Finally, thekinematic wheelchair performances are tested through asimulation conducted in the MSC-ADAMS multibodyenvironment. Conclusions: The results obtained with thesimulation show the effectiveness of the proposed solution.The wheelchair is able to climb a staircase in a safe andregular way. Following studies will complete the designof the wheelchair with the aim to build a prototype fordemonstrating the proposed working principle.Introducción: En este trabajo se analiza el comportamientode una silla de ruedas eléctrica para subir escaleras desdeun punto de vista cinemático. Wheelchair.q: El dispositivopropuesto representa la última evolución del proyecto‘Wheelchair.q’ e introduce varias mejoras con respecto a losdiseños anteriores. Esta solución actualizada cuenta conuna mayor estabilidad durante la subida de las escaleras,permitiendo llevar a cabo la tarea de una manera segura,cumpliendo la norma ISO 7176-28:2012. Sin embargo,las principales mejoras atañen a la regularidad de la trayectoriadel usuario durante la subida de escaleras, lo cualpermite obtener una percepción de comodidad mayor.Este resultado se ha logrado mediante la introducciónde un mecanismo de leva que gestiona adecuadamentela orientación del asiento en lo que se refiere al bastidorde la silla de ruedas. Con un perfil de leva apropiado, esposible compensar la oscilación introducida en la silla deruedas durante la secuencia de escalada, para que el usuariopueda obtener una trayectoria de traslación. Resultados:El diseño propuesto y su principio de funcionamiento sedescriben e ilustran en primer lugar a través de representacionesesquemáticas y gráficas, con una breve explicaciónsobre los procedimientos para obtener el perfil de leva. Acontinuación, se comparan las dos diferentes arquitecturasdel mecanismo de leva y se identifican las ventajas ydesventajas de cada solución. Por último, se prueban lasprestaciones de la silla de ruedas cinemática a través de unsimulacro en el ambiente de simulación MSC-ADAMS.Conclusiones: Los resultados obtenidos con la simulaciónmuestran la efectividad de la solución propuesta.La silla de ruedas es capaz de subir una escalera de formasegura y regular. Los siguientes estudios completarán eldiseño de la silla de ruedas con el objetivo de construir unprototipo para demostrar el principio de trabajo propuesto