1,531 research outputs found
Vision-based methods for state estimation and control of robotic systems with application to mobile and surgical robots
For autonomous systems that need to perceive the surrounding environment for the accomplishment of a given task, vision is a highly informative exteroceptive sensory source. When gathering information from the available sensors, in fact, the richness of visual data allows to provide a complete description of the environment, collecting geometrical and semantic information (e.g., object pose, distances, shapes, colors, lights). The huge amount of collected data allows to consider both methods exploiting the totality of the data (dense approaches), or a reduced set obtained from feature extraction procedures (sparse approaches). This manuscript presents dense and sparse vision-based methods for control and sensing of robotic systems. First, a safe navigation scheme for mobile robots, moving in unknown environments populated by obstacles, is presented. For this task, dense visual information is used to perceive the environment (i.e., detect ground plane and obstacles) and, in combination with other sensory sources, provide an estimation of the robot motion with a linear observer. On the other hand, sparse visual data are extrapolated in terms of geometric primitives, in order to implement a visual servoing control scheme satisfying proper navigation behaviours. This controller relies on visual estimated information and is designed in order to guarantee safety during navigation. In addition, redundant structures are taken into account to re-arrange the internal configuration of the robot and reduce its encumbrance when the workspace is highly cluttered.
Vision-based estimation methods are relevant also in other contexts. In the field of surgical robotics, having reliable data about unmeasurable quantities is of great importance and critical at the same time. In this manuscript, we present a Kalman-based observer to estimate the 3D pose of a suturing needle held by a surgical manipulator for robot-assisted suturing. The method exploits images acquired by the endoscope of the robot platform to extrapolate relevant geometrical information and get projected measurements of the tool pose. This method has also been validated with a novel simulator designed for the da Vinci robotic platform, with the purpose to ease interfacing and employment in ideal conditions for testing and validation.
The Kalman-based observers mentioned above are classical passive estimators, whose system inputs used to produce the proper estimation are theoretically arbitrary. This does not provide any possibility to actively adapt input trajectories in order to optimize specific requirements on the performance of the estimation. For this purpose, active estimation paradigm is introduced and some related strategies are presented.
More specifically, a novel active sensing algorithm employing visual dense information is described for a typical Structure-from-Motion (SfM) problem.
The algorithm generates an optimal estimation of a scene observed by a moving camera, while minimizing the maximum uncertainty of the estimation.
This approach can be applied to any robotic platforms and has been validated with a manipulator arm equipped with a monocular camera
Desenvolvimento de comportamentos para robô humanoide
Mestrado em Engenharia de Computadores e TelemáticaHumanoid robotics is an area of active research. Robots with human body
are better suited to execute tasks in environments designed for humans.
Moreover, people feel more comfortable interacting with robots that have
a human appearance. RoboCup encourages robotic research by promoting
robotic competitions. One of these competitions is the Standard Platform
League (SPL) in which humanoid robots play soccer. The robot used is
the Nao robot, created by Aldebaran Robotics. The di erence between
the teams that compete in this league is the software that controls the robots.
Another league promoted by RoboCup is the 3D Soccer Simulation
League (3DSSL). In this league the soccer game is played in a computer
simulation. The robot model used is also the one of the Nao robot. However,
there are a few di erences in the dimensions and it has one more
Degree of Freedom (DoF) than the real robot. Moreover, the simulator
cannot reproduce reality with precision. Both these leagues are relevant
for this thesis, since they use the same robot model. The objective of this
thesis is to develop behaviors for these leagues, taking advantage of the
previous work developed for the 3DSSL. These behaviors include the basic
movements needed to play soccer, namely: walking, kicking the ball, and
getting up after a fall. This thesis presents the architecture of the agent
developed for the SPL, which is similar to the architecture of the FC Portugal
team agent from the 3DSSL, hence allowing to port code between both
leagues easily. It was also developed an interface that allows to control a
leg in a more intuitive way. It calculates the joint angles of the leg, using
the following parameters: three angles between the torso and the line connecting
hip and ankle; two angles between the foot and the perpendicular
of the torso; and the distance between the hip and the ankle. It was also
developed an algorithm to calculate the three joint angles of the hip that
produce the desired vertical rotation, since the Nao robot does not have a
vertical joint in the hip. This thesis presents also the behaviors developed
for the SPL, some of them based on the existing behaviors from the 3DSSL.
It is presented a behavior that allows to create robot movements by de ning
a sequence of poses, an open-loop omnidirectional walking algorithm, and
a walk optimized in the simulator adapted to the real robot. Feedback was
added to this last walk to make it more robust against external disturbances.
Using the behaviors presented in this thesis, the robot achieved a forward
velocity of 16 cm/s, a lateral velocity of 6 cm/s, and rotated at 40 deg/s.
The work developed in this thesis allows to have an agent to control the
Nao robot and execute the basic low level behaviors for competing in the
SPL. Moreover, the similarities between the architecture of the agent for
the SPL with that of the agent from the 3DSSL allow to use the same high
level behaviors in both leagues.A robótica humanoide é uma área em ativo desenvolvimento. Os robôs com
forma humana estão melhor adaptados para executarem tarefas em ambientes
desenhados para humanos. Além disso, as pessoas sentem-se mais
confortáveis quando interagem com robôs que tenham aparência humana.
O RoboCup incentiva a investigação na área da robótica através da realização de competições de robótica. Uma destas competições é a Standard
Platform League (SPL) na qual robôs humanoides jogam futebol. O robô
usado é o robô Nao, criado pela Aldebaran Robotics. A diferença entre as
equipas que competem nesta liga está no software que controla os robôs.
Outra liga presente no RoboCup é a 3D Soccer Simulation League (3DSSL).
Nesta liga o jogo de futebol é jogado numa simulação por computador. O
modelo de robô usado é também o do robô Nao. Contudo, existem umas
pequenas diferenças nas dimensões e este tem mais um grau de liberdade do
que o robô real. O simulador também não consegue reproduzir a realidade
com perfeição. Ambas estas ligas são importantes para esta dissertação,
pois usam o mesmo modelo de robô. O objectivo desta dissertação é desenvolver
comportamentos para estas ligas, aproveitando o trabalho prévio
desenvolvido para a 3DSSL. Estes comportamentos incluem os movimentos
básicos necessários para jogar futebol, nomeadamente: andar, chutar a bola
e levantar-se depois de uma queda. Esta dissertação apresenta a arquitetura
do agente desenvolvida para a SPL, que é similar á arquitetura do agente
da equipa FC Portugal da 3DSSL, para permitir uma mais fácil partilha de
código entre as ligas. Foi também desenvolvida uma interface que permite
controlar uma perna de maneira mais intuitiva. Ela calcula os ângulos das
juntas da perna, usando os seguintes parâmetros: três ângulos entre o torso
e a linha que une anca ao tornozelo; dois ângulos entre o pé e a perpendicular
do torso; e a distância entre a anca e o tornozelo. Nesta dissertação foi
também desenvolvido um algoritmo para calcular os três ângulos das juntas
da anca que produzam a desejada rotação vertical, visto o robô Nao não
ter uma junta na anca que rode verticalmente. Esta dissertação também
apresenta os comportamentos desenvolvidos para a SPL, alguns dos quais
foram baseados nos comportamentos já existentes na 3DSSL. É apresentado
um modelo de comportamento que permite criar movimentos para o robô
de nindo uma sequência de poses, um algoritmo para um andar open-loop e
omnidirecional e um andar otimizado no simulador e adaptado para o robô
real. A este último andar foi adicionado um sistema de feedback para o
tornar mais robusto. Usando os comportamentos apresentados nesta dissertação, o robô atingiu uma velocidade de 16 cm/s para frente, 6 cm/s para
o lado e rodou sobre si pr oprio a 40 graus/s. O trabalho desenvolvido nesta
dissertação permite ter um agente que controle o robô Nao e execute os
comportamentos básicos de baixo nível para competir na SPL. Além disso,
as semelhan cas entre a arquitetura do agente para a SPL com a arquitetura
do agente da 3DSSL permite usar os mesmos comportamentos de alto nível
em ambas as ligas
Probabilistic Localization of a Soccer Robot
Mobiilsed autonoomsed robotid vajavad iseseisvaks navigeerimiseks teadmist oma umbkaudse asukoha kohta. Tihtipeale pole see otseselt tuvastatav, vaid roboti positsioon tuleb järeldada mitmete müraste sensorite mõõtmistest. Antud tees tegeleb probleemiga, kuidas lokaliseerida iseseisvat jalgpallirobotit videopildi alusel. Kasutatakse statistilisi Bayesi filtreerimise meetodeid nagu Kalmani- ja osakeste filter, mis arvestavad sellistele süsteemidele omase müra ja ebakindlusega. Implementeeritakse ja võrreldakse mitmeid erinevaid lokalisatsioonialgoritme ja testitakse neid ka lisaks simulaatorile ka füüsilise roboti peal. Töötatakse välja toimiv praktiline lahendus mobiilse jalgpalliroboti lokaliseerimiseks.The thesis deals with the problem of localizing a mobile soccer-playing robot using Bayes filtering methods. For navigating natural environments, autonomous robots need to know where they are located even if the position of the robot is not directly observable, but rather needs to be inferred from indirect measurements of several noisy sensors. The algorithms need to account for the inherent uncertainty of such systems. Several algorithms of robot positioning including Kalman filter and particle filter are investigated, implemented and compared. The algorithms are also tested on a real robot. A working solution for practical robot localization is developed
UltraSwarm: A Further Step Towards a Flock of Miniature Helicopters
We describe further progress towards the development of a
MAV (micro aerial vehicle) designed as an enabling tool to investigate aerial flocking. Our research focuses on the use of low cost off the shelf vehicles and sensors to enable fast prototyping and to reduce development costs. Details on the design of the embedded electronics and the
modification of the chosen toy helicopter are presented, and the technique used for state estimation is described. The fusion of inertial data through an unscented Kalman filter is used to estimate the helicopter’s state, and this forms the main input to the control system. Since no detailed dynamic model of the helicopter in use is available, a method is proposed for automated system identification, and for subsequent controller design based on artificial evolution. Preliminary results obtained with a dynamic simulator of a helicopter are reported, along with some encouraging results for tackling the problem of flocking
Development of a Locomotion and Balancing Strategy for Humanoid Robots
The locomotion ability and high mobility are the most distinguished features of humanoid robots. Due to the non-linear dynamics of walking, developing and controlling the locomotion of humanoid robots is a challenging task. In this thesis, we study and develop a walking engine for the humanoid robot, NAO, which is the official robotic platform used in the RoboCup Spl. Aldebaran Robotics, the manufacturing company of NAO provides a walking module that has disadvantages, such as being a black box that does not provide control of the gait as well as the robot walk with a bent knee. The latter disadvantage, makes the gait unnatural, energy inefficient and exert large amounts of torque to the knee joint. Thus creating a walking engine that produces a quality and natural gait is essential for humanoid robots in general and is a factor for succeeding in RoboCup competition.
Humanoids robots are required to walk fast to be practical for various life tasks. However, its complex structure makes it prone to falling during fast locomotion. On the same hand, the robots are expected to work in constantly changing environments alongside humans and robots, which increase the chance of collisions. Several human-inspired recovery strategies have been studied and adopted to humanoid robots in order to face unexpected and avoidable perturbations. These strategies include hip, ankle, and stepping, however, the use of the arms as a recovery strategy did not enjoy as much attention. The arms can be employed in different motions for fall prevention. The arm rotation strategy can be employed to control the angular momentum of the body and help to regain balance. In this master\u27s thesis, I developed a detailed study of different ways in which the arms can be used to enhance the balance recovery of the NAO humanoid robot while stationary and during locomotion. I model the robot as a linear inverted pendulum plus a flywheel to account for the angular momentum change at the CoM. I considered the role of the arms in changing the body\u27s moment of inertia which help to prevent the robot from falling or to decrease the falling impact. I propose a control algorithm that integrates the arm rotation strategy with the on-board sensors of the NAO. Additionally, I present a simple method to control the amount of recovery from rotating the arms. I also discuss the limitation of the strategy and how it can have a negative impact if it was misused. I present simulations to evaluate the approach in keeping the robot stable against various disturbance sources. The results show the success of the approach in keeping the NAO stable against various perturbations. Finally,I adopt the arm rotation to stabilize the ball kick, which is a common reason for falling in the soccer humanoid RoboCup competitions
Ambiente de simulação para agentes em futebol robótico
Mestrado em Engenharia de Computadores e TelemáticaO teste de algoritmos na área da robótica pode ser uma tarefa difícil, especialmente
se o teste envolver múltipos robots. Neste contexto o uso de um
simulador torna-se uma ferramenta importante no teste de algoritmos pois
permite ultrapassar algumas limitações e oferece várias vantagens.
CAMBADA é a equipa de futebol robótico da liga de tamanho médio da Universidade
de Aveiro, Portugal. A equipa está familiarizada com as limitações
do uso de robots reais para o teste de algoritmos. Devido a isso o simulador
criado pela equipa Brainstormers Tribots foi adaptado para prover um ambiente
de simulação ao software CAMBADA e estava em uso aquando do
início desta dissertação. O simulador oferecia pouca flexibilidade na modelação dos robots que resultava em comportamentos imprecisos, oferecia
também reduzida interacção com a simulação.
O objectivo desta dissertação é criar um ambiente de simulação para agentes
em futebol robótico com a intenção de melhorar o ambiente de simulação da
equipa CAMBADA. O simulador deve ser capaz de simular dinâmica de objectos
a três dimensões, sensores e actuadores ao mesmo tempo que oferece
visualização do mundo e a possibilidade de interagir com a simulação.
Da pesquisa realizada sobre simuladores robóticos o simulador Gazebo respeitava
os nossos requisitos e foi escolhido para código base do nosso simulador.
Para criar um ambiente simulado adequado à equipa CAMBADA alguns
componentes do Gazebo foram alterados e novos sensores e actuadores
virtuais foram desenvolvidos. Vários componentes do software CAMBADA
tiveram que sofrer alterações de modo a suportar um ambiente simulado. O
robot virtual foi modelado de modo a assemelhar-se com o robot real com
o objectivo de obter comportamentos mais precisos.
O simulador desenvolvido substituiu a solução anteriormente criada pela
equipa CAMBADA e foi usado nos testes de preparação para a participação
da equipa no RoboCup 2010 em Singapura onde deu o seu contributo na
obtenção do terceiro lugar.In the field of robotics, testing algorithms with the real robots can be a
di cult task, specially if the test involves more than one robot. In this
context a simulator is an important tool for testing algorithms because it
helps overcome some limitation and o ers several advantages.
CAMBADA is the RoboCup MSL soccer team of the University of Aveiro,
Portugal. The team is familiar with the limitations of using the real robots
for testing algorithms. Therefore, a simulator created by the Brainstormers
Tribots team was adapted to provide a simulated environment for their
software and was used for testing at the time of the beginning of this thesis.
The simulator offered low flexibility on the modeling of the robots from
which resulted inaccurate behaviors, it also o ered reduced interaction with
the simulation.
The purpose of this thesis is to create a simulation environment for robotic
soccer agents with the intention of improving the simulated environment for
the CAMBADA team. The simulation must provide three-dimensional dynamics
of objects, be capable of simulating sensors and actuators, allow the
visualization of the simulation and provide interaction with the simulation.
From the conducted survey about robotic simulators, the simulator Gazebo
complied with our requirements and was chosen to provide the code base
for our simulator. To create an adequate simulation environment for the
CAMBADA team some components of Gazebo were modi ed and new sensors
and actuator were developed. Several components of the CAMBADA
software had to be modified to support the simulated environment. The virtual
robot was modeled to resemble the real robot to provide more accurate
behaviors.
The developed simulator substituted the previous solution created by
CAMBADA team and was used in the preparation tests for the participation
in the RoboCup 2010 in Singapore where it contributed to obtain of
the third-place
Design of an Autonomous Agriculture Robot for Real Time Weed Detection using CNN
Agriculture has always remained an integral part of the world. As the human
population keeps on rising, the demand for food also increases, and so is the
dependency on the agriculture industry. But in today's scenario, because of low
yield, less rainfall, etc., a dearth of manpower is created in this
agricultural sector, and people are moving to live in the cities, and villages
are becoming more and more urbanized. On the other hand, the field of robotics
has seen tremendous development in the past few years. The concepts like Deep
Learning (DL), Artificial Intelligence (AI), and Machine Learning (ML) are
being incorporated with robotics to create autonomous systems for various
sectors like automotive, agriculture, assembly line management, etc. Deploying
such autonomous systems in the agricultural sector help in many aspects like
reducing manpower, better yield, and nutritional quality of crops. So, in this
paper, the system design of an autonomous agricultural robot which primarily
focuses on weed detection is described. A modified deep-learning model for the
purpose of weed detection is also proposed. The primary objective of this robot
is the detection of weed on a real-time basis without any human involvement,
but it can also be extended to design robots in various other applications
involved in farming like weed removal, plowing, harvesting, etc., in turn
making the farming industry more efficient. Source code and other details can
be found at https://github.com/Dhruv2012/Autonomous-Farm-RobotComment: Published at the AVES 2021 conference. Source code and other details
can be found at https://github.com/Dhruv2012/Autonomous-Farm-Robo
Systematic literature review of realistic simulators applied in educational robotics context
This paper presents a systematic literature review (SLR) about realistic simulators that can be applied in an educational robotics context. These simulators must include the simulation of actuators and sensors, the ability to simulate robots and their environment. During this systematic review of the literature, 559 articles were extracted from six different databases using the Population, Intervention, Comparison, Outcomes, Context (PICOC) method. After the selection process, 50 selected articles were included in this review. Several simulators were found and their features were also analyzed. As a result of this process, four realistic simulators were applied in the review’s referred context for two main reasons. The first reason is that these simulators have high fidelity in the robots’ visual modeling due to the 3D rendering engines and the second reason is because they apply physics engines, allowing the robot’s interaction with the environment.info:eu-repo/semantics/publishedVersio
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