183 research outputs found
Development of a Wearable Mechatronic Elbow Brace for Postoperative Motion Rehabilitation
This thesis describes the development of a wearable mechatronic brace for upper limb rehabilitation that can be used at any stage of motion training after surgical reconstruction of brachial plexus nerves. The results of the mechanical design and the work completed towards finding the best torque transmission system are presented herein. As part of this mechatronic system, a customized control system was designed, tested and modified. The control strategy was improved by replacing a PID controller with a cascade controller. Although the experiments have shown that the proposed device can be successfully used for muscle training, further assessment of the device, with the help of data from the patients with brachial plexus injury (BPI), is required to improve the control strategy. Unique features of this device include the combination of adjustability and modularity, as well as the passive adjustment required to compensate for the carrying angle
Robotic Automation of Turning Machines in Fenceless Production: A Planning Toolset for Economic-based Selection Optimization between Collaborative and Classical Industrial Robots
Ursprünglich wurden Industrieroboter hauptsächlich hinter Schutzzäunen betrieben, um den Sicherheitsanforderungen gerecht zu werden. Mit der Flexibilisierung der Produktion wurden diese scharfen Trennbereiche zunehmend aufgeweicht und externe Sicherheitstechnik, wie Abstandssensoren, genutzt, um Industrieroboter schutzzaunlos zu betreiben. Ausgehend vom Gedanken dieser Koexistenz bzw. Kooperation wurde die Sicherheitssensorik in den Roboter integriert, um eine wirkliche Kollaboration zu ermöglichen. Diese sogenannten kollaborierenden Roboter, oder Cobots, eröffnen neue Applikationsfelder und füllen somit die bestehenden Automatisierungslücken. Doch welche Automatisierungsvariante ist aus wirtschaftlichen Gesichtspunkten die geeignetste? Bisherige Forschung untersucht zum Großteil isoliert eine der beiden Technologien, ohne
dabei einen Systemvergleich hinsichtlich technologischer Spezifika und Wirtschaftlichkeit anzustellen. Daher widmet sich diese Dissertation einer Methodik zum wirtschaftlichen Vergleich von kollaborierenden Robotern und Industrierobotern in schutzzaunlosen Maschinenbeladungssystemen. Besonderer Fokus liegt dabei auf dem Herausarbeiten der technischen Faktoren, die die Wirtschaftlichkeit maßgeblich beeinflussen, um ein Systemverständnis der wirtschaftlichen Struktur beider Robotertechnologievarianten zu erhalten. Zur Untersuchung werden die Inhalte eines solchen Planungsvorhabens beschrieben, kategorisiert, systematisiert und modularisiert. Auf wirtschaftlicher Seite wird ein geeignetes Optimierungsmodell vorgestellt, während auf technischer Seite vor allem die Machbarkeit hinsichtlich Greifbarkeit, Layoutplanung, Robotergeschwindigkeiten und Zykluszeitbestimmung untersucht wird. Mit deduktiven, simulativen, empirischen und statistischen Methoden wird das Systemverhalten für die einzelnen Planungsinhalte analysiert, um die Gesamtwirtschaftlichkeit mit einem Minimum an Investment,- Produktions,- und Zykluszeitinformationen a priori vorhersagen zu können. Es wird gezeigt, dass durch einen Reverse Engineering Ansatz die notwendigen Planungsdaten, im Sinne von Layoutkomposition, Robotergeschwindigkeiten und Taktzeiten, mithilfe von Frontloading zu Planungsbeginn zur Verfügung gestellt werden können. Dabei dient der Kapitalwert als wirtschaftliche Bewertungsgrundlage, dessen Abhängigkeit vom Mensch-Roboter-Interaktionsgrad in einem Vorteilhaftigkeitsdiagramm für die einzelnen Technologiealternativen dargestellt werden kann. Wirtschaftlich fundierte Entscheidungen können somit auf quantitiativer Basis getroffen werden.:1. Introduction 25
1.1 Research Domain 25
1.2 Research Niche 26
1.3 Research Structure 28
2. State of the Art and Research 31
2.1 Turning Machines and Machine Tending 31
2.1.1 Tooling Machine Market Trends and Machine Tending Systems 31
2.1.2 Workpiece System 34
2.1.3 Machine System 36
2.1.4 Logistics System 39
2.1.5 Handling System 41
2.2 Robotics 43
2.2.1 Robot Installation Development and Application Fields 43
2.2.2 Fenceless Industrial and Collaborative Robots 48
2.2.3 Robot Grippers 55
2.3 Planning and Evaluation Methods 56
2.3.1 Planning of General and Manual Workstations 56
2.3.2 Cell Planning for Fully Automated and Hybrid Robot Systems 59
2.3.3 Robot Safety Planning 61
2.3.4 Economic Evaluation Methods 70
2.4 Synthesis - State of the Art and Research 71
3. Solution Approach 77
3.1 Need for Research and General Solution Approach 77
3.2 Use Case Delineation and Planning Focus 80
3.3 Economic Module – Solution Approach 86
3.4 Gripper Feasibility Module – Solution Approach 89
3.5 Rough Layout Discretization Model – Solution Approach 94
3.6 Cycle Time Estimation Module – Solution Approach 97
3.7 Collaborative Speed Estimation Module – Solution Approach 103
3.7.1 General Approach 103
3.7.2 Case 1: Quasi-static Contact with Hand 107
3.7.3 Case 2: Transient Contact with Hand 109
3.7.4 Case 3: Transient Contact with Shoulder 111
3.8 Synthesis – Solution Approach 114
4. Module Development 117
4.1 Economic Module – Module Development 117
4.1.1 General Approach 117
4.1.2 Calculation Scheme for Manual Operation 117
4.1.3 Calculation Scheme for Collaborative Robots 118
4.1.4 Calculation Scheme for Industrial Robots 120
4.2 Gripper Feasibility Module – Module Development 121
4.3 Rough Layout Discretization Module – Module Development 122
4.3.1 General Approach 122
4.3.2 Two-Dimensional Layout Pattern 123
4.3.3 Three-Dimensional Layout Pattern 125
4.4 Cycle Time Estimation Module – Module Development 126
4.4.1 General Approach 126
4.4.2 Reachability Study 127
4.4.3 Simulation Results 128
4.5 Collaborative Speed Estimation Module – Module Development 135
4.5.1 General Approach 135
4.5.2 Case 1: Quasi-static Contact with Hand 135
4.5.3 Case 2: Transient Contact with Hand 143
4.5.4 Case 3: Transient Contact with Shoulder 145
4.6 Synthesis – Module Development 149
5. Practical Verification 155
5.1 Use Case Overview 155
5.2 Gripper Feasibility 155
5.3 Layout Discretization 156
5.4 Collaborative Speed Estimation 157
5.5 Cycle Time Estimation 158
5.6 Economic Evaluation 160
5.7 Synthesis – Practical Verification 161
6. Results and Conclusions 165
6.1 Scientific Findings and Results 165
6.2 Critical Appraisal and Outlook 173Initially, industrial robots were mainly operated behind safety fences to account for the safety requirements. With production flexibilization, these sharp separation areas have been increasingly softened by utilizing external safety devices, such as distance sensors, to operate industrial robots fenceless. Based on this idea of coexistence or cooperation, safety technology has been integrated into the robot to enable true collaboration. These collaborative robots, or cobots, open up new application fields and fill the existing automation gap. But which automation variant is most suitable from an economic perspective? Present research dealt primarily isolated with one technology without comparing these systems regarding technological and economic specifics. Therefore, this doctoral thesis pursues a methodology to economically compare collaborative and industrial
robots in fenceless machine tending systems. A particular focus lies on distilling the technical factors that mainly influence the profitability to receive a system understanding of the economic structure of both robot technology variants. For examination, the contents of such a planning scheme are described, categorized, systematized, and modularized. A suitable optimization model is presented on the economic side, while the feasibility regarding gripping, layout planning, robot velocities, and cycle time determination is assessed on the technical side. With deductive, simulative, empirical, and statistical methods, the system behavior of the single planning entities is analyzed to predict the overall profitability a priori with a minimum of investment,- production,- and cycle time information. It is demonstrated that the necessary planning data, in terms of layout composition, robot velocities, and cycle times, can be frontloaded to the project’s beginning with a reverse engineering approach. The net present value serves as the target figure, whose dependency on the human-robot interaction grade can be illustrated in an advantageousness diagram for the individual technical alternatives. Consequently, sound economic decisions can be made on a quantitative basis.:1. Introduction 25
1.1 Research Domain 25
1.2 Research Niche 26
1.3 Research Structure 28
2. State of the Art and Research 31
2.1 Turning Machines and Machine Tending 31
2.1.1 Tooling Machine Market Trends and Machine Tending Systems 31
2.1.2 Workpiece System 34
2.1.3 Machine System 36
2.1.4 Logistics System 39
2.1.5 Handling System 41
2.2 Robotics 43
2.2.1 Robot Installation Development and Application Fields 43
2.2.2 Fenceless Industrial and Collaborative Robots 48
2.2.3 Robot Grippers 55
2.3 Planning and Evaluation Methods 56
2.3.1 Planning of General and Manual Workstations 56
2.3.2 Cell Planning for Fully Automated and Hybrid Robot Systems 59
2.3.3 Robot Safety Planning 61
2.3.4 Economic Evaluation Methods 70
2.4 Synthesis - State of the Art and Research 71
3. Solution Approach 77
3.1 Need for Research and General Solution Approach 77
3.2 Use Case Delineation and Planning Focus 80
3.3 Economic Module – Solution Approach 86
3.4 Gripper Feasibility Module – Solution Approach 89
3.5 Rough Layout Discretization Model – Solution Approach 94
3.6 Cycle Time Estimation Module – Solution Approach 97
3.7 Collaborative Speed Estimation Module – Solution Approach 103
3.7.1 General Approach 103
3.7.2 Case 1: Quasi-static Contact with Hand 107
3.7.3 Case 2: Transient Contact with Hand 109
3.7.4 Case 3: Transient Contact with Shoulder 111
3.8 Synthesis – Solution Approach 114
4. Module Development 117
4.1 Economic Module – Module Development 117
4.1.1 General Approach 117
4.1.2 Calculation Scheme for Manual Operation 117
4.1.3 Calculation Scheme for Collaborative Robots 118
4.1.4 Calculation Scheme for Industrial Robots 120
4.2 Gripper Feasibility Module – Module Development 121
4.3 Rough Layout Discretization Module – Module Development 122
4.3.1 General Approach 122
4.3.2 Two-Dimensional Layout Pattern 123
4.3.3 Three-Dimensional Layout Pattern 125
4.4 Cycle Time Estimation Module – Module Development 126
4.4.1 General Approach 126
4.4.2 Reachability Study 127
4.4.3 Simulation Results 128
4.5 Collaborative Speed Estimation Module – Module Development 135
4.5.1 General Approach 135
4.5.2 Case 1: Quasi-static Contact with Hand 135
4.5.3 Case 2: Transient Contact with Hand 143
4.5.4 Case 3: Transient Contact with Shoulder 145
4.6 Synthesis – Module Development 149
5. Practical Verification 155
5.1 Use Case Overview 155
5.2 Gripper Feasibility 155
5.3 Layout Discretization 156
5.4 Collaborative Speed Estimation 157
5.5 Cycle Time Estimation 158
5.6 Economic Evaluation 160
5.7 Synthesis – Practical Verification 161
6. Results and Conclusions 165
6.1 Scientific Findings and Results 165
6.2 Critical Appraisal and Outlook 17
Engineering a robotic exoskeleton for space suit simulation
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 177-181).Novel methods for assessing space suit designs and human performance capabilities are needed as NASA prepares for manned missions beyond low Earth orbit. Current human performance tests and training are conducted in space suits that are heavy and expensive, characteristics that constrain possible testing environments and reduce suit availability to researchers. Space suit mock-ups used in planetary exploration simulations are light and relatively inexpensive but do not accurately simulate the joint stiffness inherent to space suits, a key factor impacting extravehicular activity performance. The MIT Man-Vehicle Laboratory and Aurora Flight Sciences designed and built an actively controlled exoskeleton for space suit simulation called the Extravehicular Activity Space Suit Simulator (EVA S3), which can be programmed to simulate the joint torques recorded from various space suits. The goal of this research is to create a simulator that is lighter and cheaper than a traditional space suit so that it can be used in a variety of testing and training environments. The EVA S3 employs pneumatic actuators to vary joint stiffness and a pre-programmed controller to allow the experimenter to apply torque profiles to mimic various space suit designs in the field. The focus of this thesis is the design, construction, integration, and testing of the hip joint and backpack for the EVA S3. The final designs of the other joints are also described. Results from robotic testing to validate the mechanical design and control system are discussed along with the planned improvements for the next iteration of the EVA S3. The fianl EVA S3 consists of a metal and composite exoskeleton frame with pneumatic actuators that control the resistance of motion in the ankle, knee, and hip joints, and an upper body brace that resists shoulder and elbow motions with passive spring elements. The EVA S3 is lighter (26 kg excluding the tethered components) and less expensive (under $600,000 including research, design, and personnel) than a modem space suit. Design adjustments and control system improvements are still needed to achieve a desired space suit torque simulation fidelity within 10% root-mean-square error.by Forrest Edward Meyen.S.M
Design and development of robust hands for humanoid robots
Design and development of robust hands for humanoid robot
Passive Variable Compliance for Dynamic Legged Robots
Recent developments in legged robotics have found that constant stiffness passive compliant legs are an effective mechanism for enabling dynamic locomotion. In spite of its success, one of the limitations of this approach is reduced adaptability. The final leg mechanism usually performs optimally for a small range of conditions such as the desired speed, payload, and terrain. For many situations in which a small locomotion system experiences a change in any of these conditions, it is desirable to have a tunable stiffness leg for effective gait control.
To date, the mechanical complexities of designing usefully robust tunable passive compliance into legs has precluded their implementation on practical running robots. In this thesis we present an overview of tunable stiffness legs, and introduce a simple leg model that captures the spatial compliance of our tunable leg. We present experimental evidence supporting the advantages of tunable stiffness legs, and implement what we believe is the first autonomous dynamic legged robot capable of automatic leg stiffness adjustment. Finally we discuss design objectives, material considerations, and manufacturing methods that lead to robust passive compliant legs
Wearable haptic systems for the fingertip and the hand: taxonomy, review and perspectives
In the last decade, we have witnessed a drastic change in the form factor of audio and vision technologies, from heavy and grounded machines to lightweight devices that naturally fit our bodies. However, only recently, haptic systems have started to be designed with wearability in mind. The wearability of haptic systems enables novel forms of communication, cooperation, and integration between humans and machines. Wearable haptic interfaces are capable of communicating with the human wearers during their interaction with the environment they share, in a natural and yet private way. This paper presents a taxonomy and review of wearable haptic systems for the fingertip and the hand, focusing on those systems directly addressing wearability challenges. The paper also discusses the main technological and design challenges for the development of wearable haptic interfaces, and it reports on the future perspectives of the field. Finally, the paper includes two tables summarizing the characteristics and features of the most representative wearable haptic systems for the fingertip and the hand
Evaluation of a pneumatic ankle-foot orthosis: portability and functionality
There are currently many challenges in creating portable human-assistive robotics and exoskeletons, although the need for robotic human assist continues to grow. These challenges span disciplines such as control, design, fuel and efficiency, user-interfaces, neuroscience, and kinesiology. Our lab has developed a pneumatically powered ankle-foot orthosis (PPAFO) to address some of these issues.
In this dissertation, we address the issue of availability of portable pneumatic power sources, and we evaluate the short-term kinematic and metabolic impact of a bilateral, bidirectional portable powered ankle-foot orthosis (PPAFO) in an able-bodied population during over-ground walking, and we evaluate the kinematic and metabolic impact of a unilateral, bidirectional portable powered ankle-foot orthosis (PPAFO) in persons with gait impairment due to Multiple Sclerosis.
First, in Chapter 2, we address the state of portable powered pneumatic power sources. Specifically, we evaluated the use of compressed gas tanks with carbon dioxide or nitrogen as fuel. A test bench model of the PPAFO and walking trials (treadmill and over-ground) were used to evaluate each tank and gas, investigating normalized run time, minimum tank temperature, and rate of cooling. We concluded that compressed gas tanks can be used to successfully power portable pneumatic robotic platforms, especially when a recycling circuit can be implemented to increase the longevity of the fuel source, but considerations need to be taken into account in order to determine the proper fuel, based on size, weight, cost, and availability.
In Chapter 3, we evaluated a bidirectional, bilateral powered ankle-foot orthosis or exoskeleton system during over-ground walking in able-bodied individuals. With the powered PPAFOs, participants were able to reduce the metabolic power needed for walking compared to the unpowered PPAFO condition, and they were able to match the minimum metabolic power needed in shoes walking. Some kinematic changes were seen while using the PPAFOs, specifically an unexpected reduction in plantarflexion during toe-off.
In Chapters 4 and 5, we evaluated the use of a bidirectional powered ankle-foot orthosis to assist persons with gait impairment due to multiple sclerosis.
Use of the current embodiment of the portable powered AFO did not improve gait performance as measured by spatiotemporal parameters of gait. Significant differences in kinematic parameters at the ankle were observed such that the PPAFO was able to provide better assistance for foot drop during swing than the AFO or a shoes condition. Changes in kinematics at the knee were found such that the changes are likely due to compensatory reactions to the changes at the ankle induced by the footwear.
Throughout this work, we have been motivated to further research the mechanical design of the device so that users can better match their natural gait pattern in regards to spatiotemporal and kinematic parameters. Improving device design and functionality will help to determine if powered orthoses can be effective at assisting and improving gait function in persons with gait impairment
Robotic system for garment perception and manipulation
Mención Internacional en el tÃtulo de doctorGarments are a key element of people’s daily lives, as many
domestic tasks -such as laundry-, revolve around them. Performing
such tasks, generally dull and repetitive, implies devoting
many hours of unpaid labor to them, that could be freed
through automation. But automation of such tasks has been traditionally
hard due to the deformable nature of garments, that
creates additional challenges to the already existing when performing
object perception and manipulation. This thesis presents
a Robotic System for Garment Perception and Manipulation
that intends to address these challenges.
The laundry pipeline as defined in this work is composed
by four independent -but sequential- tasks: hanging, unfolding,
ironing and folding. The aim of this work is the automation of
this pipeline through a robotic system able to work on domestic
environments as a robot household companion.
Laundry starts by washing the garments, that then need to
be dried, frequently by hanging them. As hanging is a complex
task requiring bimanipulation skills and dexterity, a simplified
approach is followed in this work as a starting point, by using
a deep convolutional neural network and a custom synthetic
dataset to study if a robot can predict whether a garment will
hang or not when dropped over a hanger, as a first step towards
a more complex controller.
After the garment is dry, it has to be unfolded to ease recognition
of its garment category for the next steps. The presented
model-less unfolding method uses only color and depth information
from the garment to determine the grasp and release
points of an unfolding action, that is repeated iteratively until
the garment is fully spread.
Before storage, wrinkles have to be removed from the garment.
For that purpose, a novel ironing method is proposed,
that uses a custom wrinkle descriptor to locate the most prominent
wrinkles and generate a suitable ironing plan. The method
does not require a precise control of the light conditions of
the scene, and is able to iron using unmodified ironing tools
through a force-feedback-based controller.
Finally, the last step is to fold the garment to store it. One
key aspect when folding is to perform the folding operation in a precise manner, as errors will accumulate when several
folds are required. A neural folding controller is proposed that
uses visual feedback of the current garment shape, extracted
through a deep neural network trained with synthetic data, to
accurately perform a fold.
All the methods presented to solve each of the laundry pipeline
tasks have been validated experimentally on different robotic
platforms, including a full-body humanoid robot.La ropa es un elemento clave en la vida diaria de las personas,
no sólo a la hora de vestir, sino debido también a que muchas
de las tareas domésticas que una persona debe realizar diariamente,
como hacer la colada, requieren interactuar con ellas.
Estas tareas, a menudo tediosas y repetitivas, obligan a invertir
una gran cantidad de horas de trabajo no remunerado en
su realización, las cuales podrÃan reducirse a través de su automatización.
Sin embargo, automatizar dichas tareas ha sido
tradicionalmente un reto, debido a la naturaleza deformable de
las prendas, que supone una dificultad añadida a las ya existentes
al llevar a cabo percepción y manipulación de objetos a
través de robots. Esta tesis presenta un sistema robótico orientado
a la percepción y manipulación de prendas, que pretende
resolver dichos retos.
La colada es una tarea doméstica compuesta de varias subtareas
que se llevan a cabo de manera secuencial. En este trabajo,
se definen dichas subtareas como: tender, desdoblar, planchar
y doblar. El objetivo de este trabajo es automatizar estas tareas
a través de un sistema robótico capaz de trabajar en entornos
domésticos, convirtiéndose en un asistente robótico doméstico.
La colada comienza lavando las prendas, las cuales han de
ser posteriormente secadas, generalmente tendiéndolas al aire
libre, para poder realizar el resto de subtareas con ellas. Tender
la ropa es una tarea compleja, que requiere de bimanipulación
y una gran destreza al manipular la prenda. Por ello, en este
trabajo se ha optado por abordar una versión simplicada de
la tarea de tendido, como punto de partida para llevar a cabo
investigaciones más avanzadas en el futuro. A través de una red
neuronal convolucional profunda y un conjunto de datos de
entrenamiento sintéticos, se ha llevado a cabo un estudio sobre
la capacidad de predecir el resultado de dejar caer una prenda
sobre un tendedero por parte de un robot. Este estudio, que
sirve como primer paso hacia un controlador más avanzado,
ha resultado en un modelo capaz de predecir si la prenda se
quedará tendida o no a partir de una imagen de profundidad
de la misma en la posición en la que se dejará caer.
Una vez las prendas están secas, y para facilitar su reconocimiento
por parte del robot de cara a realizar las siguientes tareas, la prenda debe ser desdoblada. El método propuesto en
este trabajo para realizar el desdoble no requiere de un modelo
previo de la prenda, y utiliza únicamente información de profundidad
y color, obtenida mediante un sensor RGB-D, para
calcular los puntos de agarre y soltado de una acción de desdoble.
Este proceso es iterativo, y se repite hasta que la prenda se
encuentra totalmente desdoblada.
Antes de almacenar la prenda, se deben eliminar las posibles
arrugas que hayan surgido en el proceso de lavado y secado.
Para ello, se propone un nuevo algoritmo de planchado, que
utiliza un descriptor de arrugas desarrollado en este trabajo para
localizar las arrugas más prominentes y generar un plan de
planchado acorde a las condiciones de la prenda. A diferencia
de otros métodos existentes, este método puede aplicarse en un
entorno doméstico, ya que no requiere de un contol preciso de
las condiciones de iluminación. Además, es capaz de usar las
mismas herramientas de planchado que usarÃa una persona sin
necesidad de realizar modificaciones a las mismas, a través de
un controlador que usa realimentación de fuerza para aplicar
una presión constante durante el planchado.
El último paso al hacer la colada es doblar la prenda para
almacenarla. Un aspecto importante al doblar prendas es ejecutar
cada uno de los dobleces necesarios con precisión, ya que
cada error o desfase cometido en un doblez se acumula cuando
la secuencia de doblado está formada por varios dobleces
consecutivos. Para llevar a cabo estos dobleces con la precisión
requerida, se propone un controlador basado en una red neuronal,
que utiliza realimentación visual de la forma de la prenda
durante cada operación de doblado. Esta realimentación es obtenida
a través de una red neuronal profunda entrenada con
un conjunto de entrenamiento sintético, que permite estimar
la forma en 3D de la parte a doblar a través de una imagen
monocular de la misma.
Todos los métodos descritos en esta tesis han sido validados
experimentalmente con éxito en diversas plataformas robóticas,
incluyendo un robot humanoide.Programa de Doctorado en IngenierÃa Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Abderrahmane Kheddar.- Secretario: Ramón Ignacio Barber Castaño.- Vocal: Karinne RamÃrez-Amar
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