20 research outputs found
Output Feedback Image-Based Visual Servoing of Rotorcrafts
© 2018, Springer Nature B.V. This paper presents an improved output feedback based image-based visual servoing (IBVS) law for rotorcraft unmanned aerial vehicles (RUAVs). The control law enables a RUAV with a minimal set of sensors, i.e. an inertial measurement unit (IMU) and a single downward facing camera, to regulate its position and heading relative to a planar visual target consisting of multiple points. As compared to our previous work, twofold improvement is made. First, the desired value of the image feature of controlling the vertical motion of the RUAV is a function of other image features instead of a constant. This modification helps to keep the visual target stay in the camera’s field of view by indirectly adjusting the height of the vehicle. Second, the proposed approach simplifies our previous output feedback law by reducing the dimension of the observer filter state space while the same asymptotic stability result is kept. Both simulation and experimental results are presented to demonstrate the performance of the proposed controller
A review of aerial manipulation of small-scale rotorcraft unmanned robotic systems
Small-scale rotorcraft unmanned robotic systems (SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relative research in the future. In the past decade, aerial manipulation of SRURSs has attracted the interest of researchers globally. This paper provides a literature review of the last 10 years (2008–2017) on SRURSs, and details achievements and challenges. Firstly, the definition, current state, development, classification, and challenges of SRURSs are introduced. Then, related papers are organized into two topical categories: mechanical structure design, and modeling and control. Following this, research groups involved in SRURS research and their major achievements are summarized and classified in the form of tables. The research groups are introduced in detail from seven parts. Finally, trends and challenges are compiled and presented to serve as a resource for researchers interested in aerial manipulation of SRURSs. The problem, trends, and challenges are described from three aspects. Conclusions of the paper are presented, and the future of SRURSs is discussed to enable further research interests
Observer-based Controller for VTOL-UAVs Tracking using Direct Vision-Aided Inertial Navigation Measurements
This paper proposes a novel observer-based controller for Vertical Take-Off
and Landing (VTOL) Unmanned Aerial Vehicle (UAV) designed to directly receive
measurements from a Vision-Aided Inertial Navigation System (VA-INS) and
produce the required thrust and rotational torque inputs. The VA-INS is
composed of a vision unit (monocular or stereo camera) and a typical low-cost
6-axis Inertial Measurement Unit (IMU) equipped with an accelerometer and a
gyroscope. A major benefit of this approach is its applicability for
environments where the Global Positioning System (GPS) is inaccessible. The
proposed VTOL-UAV observer utilizes IMU and feature measurements to accurately
estimate attitude (orientation), gyroscope bias, position, and linear velocity.
Ability to use VA-INS measurements directly makes the proposed observer design
more computationally efficient as it obviates the need for attitude and
position reconstruction. Once the motion components are estimated, the
observer-based controller is used to control the VTOL-UAV attitude, angular
velocity, position, and linear velocity guiding the vehicle along the desired
trajectory in six degrees of freedom (6 DoF). The closed-loop estimation and
the control errors of the observer-based controller are proven to be
exponentially stable starting from almost any initial condition. To achieve
global and unique VTOL-UAV representation in 6 DoF, the proposed approach is
posed on the Lie Group and the design in unit-quaternion is presented. Although
the proposed approach is described in a continuous form, the discrete version
is provided and tested. Keywords: Vision-aided inertial navigation system,
unmanned aerial vehicle, vertical take-off and landing, stochastic, noise,
Robotics, control systems, air mobility, observer-based controller algorithm,
landmark measurement, exponential stability
Development and applications of a vision-based unmanned helicopter
Ph.DDOCTOR OF PHILOSOPH
System Architectures for Cooperative Teams of Unmanned Aerial Vehicles Interacting Physically with the Environment
Unmanned Aerial Vehicles (UAVs) have become quite a useful tool for a wide range of
applications, from inspection & maintenance to search & rescue, among others. The
capabilities of a single UAV can be extended or complemented by the deployment
of more UAVs, so multi-UAV cooperative teams are becoming a trend. In that case,
as di erent autopilots, heterogeneous platforms, and application-dependent software
components have to be integrated, multi-UAV system architectures that are fexible
and can adapt to the team's needs are required.
In this thesis, we develop system architectures for cooperative teams of UAVs,
paying special attention to applications that require physical interaction with the
environment, which is typically unstructured. First, we implement some layers to
abstract the high-level components from the hardware speci cs. Then we propose
increasingly advanced architectures, from a single-UAV hierarchical navigation architecture
to an architecture for a cooperative team of heterogeneous UAVs. All
this work has been thoroughly tested in both simulation and eld experiments in
di erent challenging scenarios through research projects and robotics competitions.
Most of the applications required physical interaction with the environment, mainly
in unstructured outdoors scenarios. All the know-how and lessons learned throughout
the process are shared in this thesis, and all relevant code is publicly available.Los vehículos aéreos no tripulados (UAVs, del inglés Unmanned Aerial Vehicles) se han
convertido en herramientas muy valiosas para un amplio espectro de aplicaciones, como
inspección y mantenimiento, u operaciones de rescate, entre otras. Las capacidades de un
único UAV pueden verse extendidas o complementadas al utilizar varios de estos vehículos
simultáneamente, por lo que la tendencia actual es el uso de equipos cooperativos con
múltiples UAVs. Para ello, es fundamental la integración de diferentes autopilotos,
plataformas heterogéneas, y componentes software -que dependen de la aplicación-, por lo
que se requieren arquitecturas multi-UAV que sean flexibles y adaptables a las necesidades
del equipo.
En esta tesis, se desarrollan arquitecturas para equipos cooperativos de UAVs, prestando
una especial atención a aplicaciones que requieran de interacción física con el entorno,
cuya naturaleza es típicamente no estructurada. Primero se proponen capas para abstraer a
los componentes de alto nivel de las particularidades del hardware. Luego se desarrollan
arquitecturas cada vez más avanzadas, desde una arquitectura de navegación para un
único UAV, hasta una para un equipo cooperativo de UAVs heterogéneos. Todo el trabajo ha
sido minuciosamente probado, tanto en simulación como en experimentos reales, en
diferentes y complejos escenarios motivados por proyectos de investigación y
competiciones de robótica. En la mayoría de las aplicaciones se requería de interacción
física con el entorno, que es normalmente un escenario en exteriores no estructurado. A lo
largo de la tesis, se comparten todo el conocimiento adquirido y las lecciones aprendidas en
el proceso, y el código relevante está publicado como open-source
Aerial Vehicles
This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space
MODELING AND INTELLIGENT CONTROL OF A DRONE
This thesis tackles the modeling, design, and control of a Quadrotor unmanned aerial
vehicle, with a focus on intelligent control and smart applications such as obstacle
avoidance, robust trajectory tracking, visual soft landing, and disturbance compensation. It details the mathematical modeling opted for the simulation and the control.
Furthermore, It describes the classic control methodology for both linear and nonlinear control techniques with interpreted simulations; The methodology is subsequently
applied to develop an open-source autonomous quadrotor miniature model. In addition, advanced control theory has been applied using Adaptive Linear Quadratic
Gaussian, Model predictive control, and intelligent Radial basis functions neural network for the robust tracking of generated trajectory for either obstacle avoidance or
bio-inspired soft landing on a specially designed landing pad. The thesis depicts as
well the adaptive optimal observation by an enhanced Kalman filter combined with
Madgwick sensor’s data fuse. Control laws were mainly either mathematically derived
or adaptively generated based on stability analysis using Lyapunov theory, The simulation incorporated several analytical comparisons to prove efficiency and compare
the performance