1,780 research outputs found
Carrozzina elettrica innovativa per il superamento delle barriere architettoniche
No full textLa 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
Design of a self-leveling cam mechanism for a stair climbing wheelchair
No full textThis 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
Design and construction of a new version of the Epi.q UGV for monitoring and surveillance tasks
No full textThe 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
Design of a reconfiguration mechanism for an electric stair-climbing wheelchair
No full textIn this paper is described a new solution for a stair-climbing wheelchair: a device that allows disabled people to autonomously overcome architectural barriers. The paper presents the evolution of a project introduced in previous works. The aim is to obtain a wheelchair able to move both in structured and unstructured environments and overcome single steps or an entire staircase. The innovative aspect of this work is the introduction of a hybrid solution, with a locomotion system based on wheels and an idle track for the vehicle stability. The locomotion group permits to overcome obstacles through an original architecture based on an epicycloidal transmission. The control logic manages the motors that drive independently the two degrees of freedom of the transmission and allows to switch from an advancing mode to a climbing one. The wheelchair must be able to move in different environments, such as flat ground or stairs, which require different specifications, sometimes in contrast. For this reason the main part of the work regards the design of a reconfiguration mechanism able to prepare the wheelchair for different working conditions. First of all the relative positions between the elements that compose the wheelchair structure in different configuration are studied in order to optimize the performances especially in terms of regularity. Then several possible solutions for the reconfiguration mechanism are presented and qualitatively evaluated, in order to choose the one that satisfy the design specifications
Evolution of Wheelchair.q, a Stair-climbing Wheelchair
No full textThis 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
Analysis of the Static Stability for an Electric Stair-Climbing Wheelchair
No full textIn this paper, an electric stair-climbing wheelchair is presented. The
proposed solution is based on a smart hybrid leg-wheel locomotion system. This
idea has been developed through several wheelchair concepts presented in the
first part of the paper, pointing out the main advantages and disadvantages for
each solution. In the second part, an optimization procedure regarding the
geometry of the latest wheelchair architecture is presented. The aim is to
maximize the wheelchair performances in terms of safety and comfort for the
user. In particular, the geometric parameters of the wheelchair structure have
been analysed in order to assess which configuration guarantees an acceptable
static stability of the wheelchair during stair climbing motion. Moreover, considering
the goal of maximizing the comfort for the user, the oscillation introduced
on the wheelchair seat by the locomotion system has been studied and
solutions able to reduce them are proposed
CARROZZINA ELETTRICA MONTASCALE CON SISTEMA DI LOCOMOZIONE IBRIDO
No full textLa presente invenzione riguarda una carrozzina montascale (1) comprendente un
telaio (2) provvisto di un sedile (3) destinato ad ospitare un utente (100) da
trasportare e un’unità di locomozione (4) comprendente una coppia di tripodi (40).
La carrozzina (1) comprende inoltre mezzi di appoggio passivi mobili tra una
posizione riposta in cui sono sollevati dal terreno (1a) e una posizione estratta in cui
sono a contatto con il terreno (1a). I mezzi di appoggio passivi comprendono un
cingolo (6) configurato in modo tale che in posizione estratta il telaio (2) appoggia
anteriormente sull’unità di locomozione (4) e posteriormente sul cingolo (6), e la
carrozzina montascale (1) comprende ulteriormente almeno un dispositivo
meccanico collegato tra l’unità di locomozione (4) e il sedile (3) e atto a cooperare con
il cingolo (6) per compensare le oscillazioni del sedile (3) generate dal movimento
della coppia di tripodi (40), l’almeno un dispositivo meccanico essendo configurato
in modo tale da permettere un moto traslatorio del sedile (3) durante l’avanzamento
della carrozzina montascale (1) sulle scale
Path Tracking Experimentation With Epi.q-Mod 2: An Obstacle Climbing Mobile Robot
No full textIn this paper, an experimental activity on the path tracking for a hybrid wheeled-legged mobile robot is presented. The activity has been conducted on the Epi.q-Mod 2 prototype, a mobile robot with obstacle climbing ability. This feature has been obtained using a smart rotating leg architecture. Unfortunately, this solution introduces complexity on the kinematic and dynamic modeling of the robot. In order to understand the behavior of the robot during the motion on a generic trajectory, an open loop position controller has been implemented. In particular, the experimental robot trajectory has been reconstructed from odometric quantities through a simplified kinematic model. This trajectory has been compared with the trajectory obtained from a multibody model of the real prototype in order to evaluate the differences between the two approaches. This activity represents a preliminary step for the development of a self-guidance vehicle. In future works the developed model will be used to provide a position feedback for a closed loop position controller without the necessity to use additional sensors
Kinematic analysis of an electric stair-climbing wheelchair
No full textThis paper presents the functional design and kinematic synthesis of a recent version of an electric stair-climbing wheelchair. The proposed device represents the latest evolution of the ‘Wheelchair.q' project and introduces several improvements over previous designs. This updated solution has greater stability during stair-climbing operation, and it satisfies the safety requirements introduced by ISO 7176-28:2012, "Requirements and test methods for stair-climbing devices". The main improvement presented concerns the regularity of the user trajectory during stair-climbing, which ensures a more comfortable perception. This result has been achieved by introducing a cam mechanism between the frame connected to the locomotion unit and the seat frame, which properly manages the seat orientation. With an appropriate cam profile, it is possible to compensate for the oscillations that are introduced on the wheelchair during the climbing sequence and allow the user to obtain a translational trajectory. The proposed design and its working principle are first described and illustrated through schematic and graphic representations. A brief explanation of the procedure for obtaining the cam profile is also given. Two different architectures for the cam mechanism are then compared, and the advantages and disadvantages for each solution are identified. Finally, the kinematic wheelchair performances are tested through a simulation conducted in the MSC-ADAMS multibody environment
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