7 research outputs found
Design and Control of a Hand Prosthesis
Práce pĹ™edkládá metody a vĂ˝sledky návrhu, vĂ˝roby a vĂ˝zkumu pÄ›tiprstĂ© protĂ©zy ruky. Inspirace jdoucĂ z pĹ™Ărody a z toho vyvozenĂ˝ princip pouĹľitĂ©ho mechanizmu je uveden. ZákladnĂ koncept Ĺ™ĂdĂcĂho schĂ©ma zaloĹľenĂ©ho na procesingu a ohodnocenĂ EMG je navrhnut a implementován. Části senzorickĂ©ho systĂ©mu protĂ©zy jsou navrhnuty a zahrnuty do rĂdĂcĂho algoritmu a shĂ©matu. VelkĂ© mnoĹľstvĂ inovacĂ a návrhĹŻ pro budoucĂ práce a vĂ˝zkum jsou prezentovány, stejnÄ› tak komplexnĂ analĂ˝za a diskuse dosaĹľenĂ˝ch a moĹľnĂ˝ch budoucĂch vĂ˝sledkĹŻ.The text shows idea flow, methods and results in design, manufacture and research of five--fingered prosthetic hand. The inspiration of the nature and mechanical principle elicited is presented. Fundamental control scheme based on processing and evaluation of EMG is designed and implemented. The segments of sensory system are designed and involved into the overall controll scheme idea. Large innovations and suggestions for future work and research are given with complex discussion through reached and hopefully future results.
Control of multifunctional prosthetic hands by processing the electromyographic signal
The human hand is a complex system, with a large number of degrees of freedom (DoFs), sensors embedded in its structure, actuators and tendons, and a complex hierarchical control. Despite this complexity, the efforts required to the user to carry out the different movements is quite small (albeit after an appropriate and lengthy training). On the contrary, prosthetic hands are just a pale replication of the natural hand, with significantly reduced grasping capabilities and no sensory information delivered back to the user. Several attempts have been carried out to develop multifunctional prosthetic devices controlled by electromyographic (EMG) signals (myoelectric hands), harness (kinematic hands), dimensional changes in residual muscles, and so forth, but none of these methods permits the "natural" control of more than two DoFs. This article presents a review of the traditional methods used to control artificial hands by means of EMG signal, in both the clinical and research contexts, and introduces what could be the future developments in the control strategy of these devices
On the development of a cybernetic prosthetic hand
The human hand is the end organ of the upper limb, which in humans serves the important
function of prehension, as well as being an important organ for sensation and communication.
It is a marvellous example of how a complex mechanism can be implemented,
capable of realizing very complex and useful tasks using a very effective combination of
mechanisms, sensing, actuation and control functions.
In this thesis, the road towards the realization of a cybernetic hand has been presented.
After a detailed analysis of the model, the human hand, a deep review of the state of the
art of artificial hands has been carried out. In particular, the performance of prosthetic
hands used in clinical practice has been compared with the research prototypes, both for
prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by
comparing the characteristics of these hands with the natural model, the human hand, the
limitations of current artificial devices will be put in evidence, thus outlining the design
goals for a new cybernetic device.
Three hand prototypes with a high number of degrees of freedom have been realized and
tested: the first one uses microactuators embedded inside the structure of the fingers, and
the second and third prototypes exploit the concept of microactuation in order to increase
the dexterity of the hand while maintaining the simplicity for the control. In particular, a
framework for the definition and realization of the closed-loop electromyographic control of
these devices has been presented and implemented.
The results were quite promising, putting in evidence that, in the future, there could
be two different approaches for the realization of artificial devices. On one side there
could be the EMG-controlled hands, with compliant fingers but only one active degree of
freedom. On the other side, more performing artificial hands could be directly interfaced
with the peripheral nervous system, thus establishing a bi-directional communication with
the human brain
Design of an underactuated compliant gripper for surgery using nitinol
Design of an Underactuated Complimant Gripper for surgery Using Nitinol -- Joint Design -- Underactuated Finger Design -- Optimization of the Transmission Mechanism -- Optimization of the Driving Mechanism -- Finite Element Simulation
Modeling and control of an anthropomorphic robotic hand
MenciĂłn Europea en el tĂtulo de doctorThis thesis presents methods and tools for enabling the successful use of
robotic hands. For highly dexterous and/or anthropomorphic robotic hands,
these methods have to share some common goals, such as overcoming the
potential complexity of the mechanical design and the ability of performing
accurate tasks with low and efficient computational cost.
A prerequisite for dexterity is to increase the workspace of the robotic hand.
For this purpose, the robotic hand must be considered as a single multibody
system. Solving the inverse kinematics problem of the whole robotic hand is
an arduous task due to the high number of degrees of freedom involved and
the possible mechanical limitations, singularities and other possible constraints.
The redundancy has proven to be of a great usefulness for dealing
with potential constraints. To be able to exploit the redundancy for dealing
with constraints, the adopted method for solving the inverse kinematics
must be robust and extendable. Obviously, addressing such complex problem,
the method will certainly be computationally heavy. Thus, one of the
aims of this thesis is to resolve the inverse kinematics problem of the whole
robotic hand under constraints, taking into account the computational cost.
To this end, this thesis extends and reduces the most recent Selectively
Damped Least Squares method which is based on the computation of all
singular values, to deal with constraints with a minimum computational
cost. New estimation algorithm of singular values and their corresponding
singular vectors is proposed to reduce the computational cost. The reduced
extended selectively damped least squares method is simulated and experimentally
evaluated using an anthropomorphic robotic hand as a test bed.
On the other hand, dexterity depends not only on the accuracy of the position
control, but also on the exerted forces. The tendon driven modern robotic hands, like the one used in this work, are strongly nonlinear dynamic
systems, where motions and forces are transmitted remotely to the
finger joints. The problem of modeling and control of position and force
simultaneously at low level control is then considered. A new hybrid control
structure based on the succession of two sliding mode controllers is
proposed. The force is controlled by its own controller which does not need
a contact model. The performance of the proposed controller is evaluated
by performing the force control directly using the force sensor information
of the fingertip, and indirectly using the torque control of the actuator.
Finally, we expect that the applications of the methods presented in this
thesis can be extended to cover different issues and research fields and in
particular they can be used in a variety of algorithm that require the estimation
of singular values.This work was partially supported by the European project HANDLE, FP7-231640, and by the Spanish ministry MICINN through FPI scholarship within the project DPI-2005-04302.Programa Oficial de Doctorado en IngenierĂa ElĂ©ctrica, ElectrĂłnica y AutomáticaPresidente: Anis Sahbani.- Secretario: Fares Jawad Moh D Abu-Dakka.- Vocal: Claudio Ross
MetodologĂa de diseño de manos robĂłticas basada en los estados de su sistema accionador
La mano humana es una de las herramientas más asombrosas de la naturaleza, tanto que no ha podido ser superada en ningĂşn aspecto hasta el momento. Siendo el principal medio por el cual se ha creado y construido, directa o indirectamente, todo lo artificial que actualmente nos rodea, es natural pensar de que gran parte de la comunidad cientĂfica relacionada con la robĂłtica dedique grandes esfuerzos por imitarla. En la actualidad se puede realizar un extenso catálogo de manos robĂłticas desarrolladas y todas buscan resolver un determinado comportamiento de la mano humana, aĂşn asĂ, Ă©stas se pueden dividir en tres grupos bien definidos: las pinzas robĂłticas, las cuales se caracterizan por su aplicaciĂłn industrial en tareas de agarre firme de elementos especĂficos y por su robustez, precio y vida Ăştil; por otro lado, están las manos robĂłticas subactuadas en las que se buscan mecanismos cada vez más complejos que hagan disminuir la cantidad de actuadores y la complejidad de su sistema de control a favor de mejorar la funcionalidad de las pinzas robĂłticas en lo que se refiere a extender su capacidad de agarre a objetos con formas y tamaños cada vez más diferentes; y finalmente encontramos las demás manos robĂłticas en las que su objetivo es la experimentaciĂłn de un determinado comportamiento de la mano humana más centrada en las tareas de manipulaciĂłn. Esta tesis propone una metodologĂa de diseño de manos robĂłticas desde un punto de vista particular, que es el de los estados que puede ofrecer su sistema de accionamiento, teniendo en cuenta la capacidad de combinarlos y hacerlos independientes. Los elementos mĂłviles que componen una mano robĂłtica son accionados por un actuador o conjunto de actuadores. El sistema accionador es el Ăłrgano principal que da vida a un determinado sistema robĂłtico como una mano robĂłtica, por lo tanto es preciso identificar la capacidad que tiene el mismo de hacer que ese movimiento pueda generar tareas cada vez más complejas. La forma de identificar esta capacidad se resume en los estados y la calidad de los mismos que el sistema accionador puede ofrecer. Esta metodologĂa de diseño se basa fundamentalmente en este concepto y que si bien en este trabajo es aplicado a manos robĂłticas, puede ser extendido a cualquier sistema robĂłtico que disponga de un sistema accionador y de esta forma optimizar sus recursos no sĂłlo a nivel funcional, sino tambiĂ©n en el ahorro de energĂa. En el transcurso de este trabajo se han diseñado dos manos robĂłticas con esta metodologĂa y se ha realizado un ensayo de viabilidad tĂ©cnica de un actuador capaz de ofrecer un nĂşmero finito de estados mayor a los tres que ofrece actualmente cualquier actuador. Estos diseños han demostrado que este tipo de metodologĂa puede ofrecer una alternativa para la optimizaciĂłn del sistema accionador de una mano robĂłtica. Por otro lado, la misma tambiĂ©n puede ser aplicada a cualquier tipo de mano robĂłtica y para cualquier aplicaciĂłn y servir como una herramienta Ăştil para el análisis del diseño de las manos robĂłticas actuales y buscar puntos de optimizaciĂłn para futuros desarrollos
Soft Robotics: Design for Simplicity, Performance, and Robustness of Robots for Interaction with Humans.
This thesis deals with the design possibilities concerning the next generation of advanced Robots. Aim of the work is to study, analyse and realise artificial systems that are essentially simple, performing and robust and can live and coexist with humans. The main design guideline followed in doing so is the Soft Robotics Approach, that implies the design of systems with intrinsic mechanical compliance in their architecture. The first part of the thesis addresses design of new soft robotics actuators, or robotic muscles. At the beginning are provided information about what a robotic muscle is and what is needed to realise it. A possible classification of these systems is analysed and some criteria useful for their comparison are explained. After, a set of functional specifications and parameters is identified and defined, to characterise a specific subset of this kind of actuators, called Variable Stiffness Actuators. The selected parameters converge in a data-sheet that easily defines performance and abilities of the robotic system. A complete strategy for the design and realisation of this kind of system is provided, which takes into account their me- chanical morphology and architecture. As consequence of this, some new actuators are developed, validated and employed in the execution of complex experimental tasks. In particular the actuator VSA-Cube and its add-on, a Variable Damper, are developed as the main com- ponents of a robotics low-cost platform, called VSA-CubeBot, that
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can be used as an exploratory platform for multi degrees of freedom experiments. Experimental validations and mathematical models of the system employed in multi degrees of freedom tasks (bimanual as- sembly and drawing on an uneven surface), are reported.
The second part of the thesis is about the design of multi fingered hands for robots. In this part of the work the Pisa-IIT SoftHand is introduced. It is a novel robot hand prototype designed with the purpose of being as easily usable, robust and simple as an industrial gripper, while exhibiting a level of grasping versatility and an aspect comparable to that of the human hand. In the thesis the main theo- retical tool used to enable such simplification, i.e. the neuroscience– based notion of soft synergies, are briefly reviewed. The approach proposed rests on ideas coming from underactuated hand design. A synthesis method to realize a desired set of soft synergies through the principled design of adaptive underactuated mechanisms, which is called the method of adaptive synergies, is discussed. This ap- proach leads to the design of hands accommodating in principle an arbitrary number of soft synergies, as demonstrated in grasping and manipulation simulations and experiments with a prototype. As a particular instance of application of the method of adaptive syner- gies, the Pisa–IIT SoftHand is then described in detail. The design and implementation of the prototype hand are shown and its effec- tiveness demonstrated through grasping experiments. Finally, control of the Pisa/IIT Hand is considered. Few different control strategies are adopted, including an experimental setup with the use of surface Electromyographic signals