scholarly journals Vision-based SLAM system for MAVs in GPS-denied environments

2017 ◽  
Vol 9 (4) ◽  
pp. 283-296 ◽  
Author(s):  
Sarquis Urzua ◽  
Rodrigo Munguía ◽  
Antoni Grau
Keyword(s):  
Sensory Input ◽  
Low Cost ◽  
Real Data ◽  
Micro Aerial Vehicle ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Payload Capacity ◽  
The World ◽  
Aerial Vehicle ◽  
Metric Scale

Using a camera, a micro aerial vehicle (MAV) can perform visual-based navigation in periods or circumstances when GPS is not available, or when it is partially available. In this context, the monocular simultaneous localization and mapping (SLAM) methods represent an excellent alternative, due to several limitations regarding to the design of the platform, mobility and payload capacity that impose considerable restrictions on the available computational and sensing resources of the MAV. However, the use of monocular vision introduces some technical difficulties as the impossibility of directly recovering the metric scale of the world. In this work, a novel monocular SLAM system with application to MAVs is proposed. The sensory input is taken from a monocular downward facing camera, an ultrasonic range finder and a barometer. The proposed method is based on the theoretical findings obtained from an observability analysis. Experimental results with real data confirm those theoretical findings and show that the proposed method is capable of providing good results with low-cost hardware.

scholarly journals Minimalistic approach for monocular SLAM system applied to micro aerial vehicles in GPS-denied environments

2018 ◽  
Vol 40 (16) ◽  
pp. 4345-4357 ◽  
Author(s):  
Sarquis Urzua ◽  
Rodrigo Munguía ◽  
Emmanuel Nuño ◽  
Antoni Grau
Keyword(s):  
Low Cost ◽  
Sufficient Conditions ◽  
Real Data ◽  
Simplified Model ◽  
Micro Aerial Vehicles ◽  
Aerial Vehicles ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Theoretical Results ◽  
Metric Scale

In this work, a novel monocular simultaneous localization and mapping (SLAM) system with application to micro aerial vehicles is proposed. The main difference with respect to previous approaches is that a barometer is used as a unique sensory aid for incorporating altitude information into the system in order to recover an absolute metric scale. First, an observability analysis of a simplified model of a monocular SLAM system is developed. From this analysis, several theoretical results are derived. Among others, one important result is related to the fact that the metric scale can become observable when measurements of altitude are included in the system. In this case, sufficient conditions for observability are presented. The design of the proposed method is based on these theoretical results. Simulations and experiments with real data are presented to validate the proposed approach. The results confirm that the metric scale can be retrieved by including altitude measurements in the system. It is also shown that the proposed method can be practically implemented, using low-cost sensors, to perform visual-based navigation in GPS-denied environments.

scholarly journals Monocular SLAM for Visual Odometry: A Full Approach to the Delayed Inverse-Depth Feature Initialization Method

2012 ◽  
Vol 2012 ◽  
pp. 1-26 ◽  
Author(s):  
Rodrigo Munguía ◽  
Antoni Grau
Keyword(s):  
Sensory Input ◽  
A Priori ◽  
Real Data ◽  
Visual Odometry ◽  
Visual Features ◽  
Single Camera ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Freely Moving ◽  
Depth Feature

This paper describes in a detailed manner a method to implement a simultaneous localization and mapping (SLAM) system based on monocular vision for applications of visual odometry, appearance-based sensing, and emulation of range-bearing measurements. SLAM techniques are required to operate mobile robots ina prioriunknown environments using only on-board sensors to simultaneously build a map of their surroundings; this map will be needed for the robot to track its position. In this context, the 6-DOF (degree of freedom) monocular camera case (monocular SLAM) possibly represents the harder variant of SLAM. In monocular SLAM, a single camera, which is freely moving through its environment, represents the sole sensory input to the system. The method proposed in this paper is based on a technique called delayed inverse-depth feature initialization, which is intended to initialize new visual features on the system. In this work, detailed formulation, extended discussions, and experiments with real data are presented in order to validate and to show the performance of the proposal.

Robust attitude control design for a low-cost hexarotor micro aerial vehicle

2016 ◽  
Vol 38 (6) ◽  
pp. 701-721 ◽  
Author(s):  
Dafizal Derawi ◽  
Nurul Dayana Salim ◽  
Hairi Zamzuri ◽  
Mohd Azizi Abdul Rahman ◽  
Kenzo Nonami
Keyword(s):  
Attitude Control ◽  
Low Cost ◽  
Control Design ◽  
Micro Aerial Vehicle ◽  
Aerial Vehicle

scholarly journals Monocular Visual SLAM Based on a Cooperative UAV–Target System

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3531 ◽  
Author(s):  
Juan-Carlos Trujillo ◽  
Rodrigo Munguia ◽  
Sarquis Urzua ◽  
Edmundo Guerra ◽  
Antoni Grau
Keyword(s):  
A Priori ◽  
Target Position ◽  
Real Data ◽  
Good Alternative ◽  
Lyapunov Theory ◽  
Target System ◽  
Operational Environment ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Reliable Solution

To obtain autonomy in applications that involve Unmanned Aerial Vehicles (UAVs), the capacity of self-location and perception of the operational environment is a fundamental requirement. To this effect, GPS represents the typical solution for determining the position of a UAV operating in outdoor and open environments. On the other hand, GPS cannot be a reliable solution for a different kind of environments like cluttered and indoor ones. In this scenario, a good alternative is represented by the monocular SLAM (Simultaneous Localization and Mapping) methods. A monocular SLAM system allows a UAV to operate in a priori unknown environment using an onboard camera to simultaneously build a map of its surroundings while at the same time locates itself respect to this map. So, given the problem of an aerial robot that must follow a free-moving cooperative target in a GPS denied environment, this work presents a monocular-based SLAM approach for cooperative UAV–Target systems that addresses the state estimation problem of (i) the UAV position and velocity, (ii) the target position and velocity, (iii) the landmarks positions (map). The proposed monocular SLAM system incorporates altitude measurements obtained from an altimeter. In this case, an observability analysis is carried out to show that the observability properties of the system are improved by incorporating altitude measurements. Furthermore, a novel technique to estimate the approximate depth of the new visual landmarks is proposed, which takes advantage of the cooperative target. Additionally, a control system is proposed for maintaining a stable flight formation of the UAV with respect to the target. In this case, the stability of control laws is proved using the Lyapunov theory. The experimental results obtained from real data as well as the results obtained from computer simulations show that the proposed scheme can provide good performance.

scholarly journals An Image-Based Real-Time Georeferencing Scheme for a UAV Based on a New Angular Parametrization

2020 ◽  
Vol 12 (19) ◽  
pp. 3185
Author(s):  
Ehsan Khoramshahi ◽  
Raquel A. Oliveira ◽  
Niko Koivumäki ◽  
Eija Honkavaara
Keyword(s):  
Real Time ◽  
Satellite System ◽  
Local Networks ◽  
Ground Control Points ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Aerial Vehicle ◽  
Gimbal Lock ◽  
Global Navigation Satellite ◽  
Pyramid Matching

Simultaneous localization and mapping (SLAM) of a monocular projective camera installed on an unmanned aerial vehicle (UAV) is a challenging task in photogrammetry, computer vision, and robotics. This paper presents a novel real-time monocular SLAM solution for UAV applications. It is based on two steps: consecutive construction of the UAV path, and adjacent strip connection. Consecutive construction rapidly estimates the UAV path by sequentially connecting incoming images to a network of connected images. A multilevel pyramid matching is proposed for this step that contains a sub-window matching using high-resolution images. The sub-window matching increases the frequency of tie points by propagating locations of matched sub-windows that leads to a list of high-frequency tie points while keeping the execution time relatively low. A sparse bundle block adjustment (BBA) is employed to optimize the initial path by considering nuisance parameters. System calibration parameters with respect to global navigation satellite system (GNSS) and inertial navigation system (INS) are optionally considered in the BBA model for direct georeferencing. Ground control points and checkpoints are optionally included in the model for georeferencing and quality control. Adjacent strip connection is enabled by an overlap analysis to further improve connectivity of local networks. A novel angular parametrization based on spherical rotation coordinate system is presented to address the gimbal lock singularity of BBA. Our results suggest that the proposed scheme is a precise real-time monocular SLAM solution for a UAV.

Towards the Design of a Fully Actuated Invertible Flying Quadrotor MAV

2013 ◽  
Author(s):  
Andreas Gelardos ◽  
David J. Cappelleri
Keyword(s):  
Closed Loop ◽  
Mechanical Design ◽  
Low Cost ◽  
Open Loop ◽  
Transmission Mechanism ◽  
Micro Aerial Vehicle ◽  
Loop Control ◽  
Minimal Weight ◽  
Control Scheme ◽  
Aerial Vehicle

In this paper, we present the transmission mechanism design for a fully actuated Invertible Flying Quadrotor (IFQ) micro aerial vehicle (MAV). At the heart of the mechanism is a gearbox which couples and counter rotates two pairs of shafts that have the quadrotor propellers mounted at their ends. This mechanism will allow for the IFQ to follow aggressive maneuvers, hover at an arbitrary attitude, and have sustained inverted flight capabilities. The paper presents the mechanical design challenges and solutions in designing such a transmission mechanism with minimal weight along with low cost and easy manufacturing. The dynamic model for the IFQ MAV is presented along with an optimal open loop trajectory control scheme and related simulations. An approach for a full closed loop control scheme is also discussed. A prototype of the mechanism has been manufactured and functionally tested. The entire transmission mechanism was able to be prototyped with a weight of only approximately 100 grams.

scholarly journals Parallel Tracking and Mapping for Controlling VTOL Airframe

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Michal Jama ◽  
Dale Schinstock
Keyword(s):  
Traditional Approach ◽  
Video Stream ◽  
Monocular Vision ◽  
Map Building ◽  
Depth Cameras ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Aerial Vehicle ◽  
Improved Performance ◽  
Slam Algorithm

This work presents a vision based system for navigation on a vertical takeoff and landing unmanned aerial vehicle (UAV). This is a monocular vision based, simultaneous localization and mapping (SLAM) system, which measures the position and orientation of the camera and builds a map of the environment using a video stream from a single camera. This is different from past SLAM solutions on UAV which use sensors that measure depth, like LIDAR, stereoscopic cameras or depth cameras. Solution presented in this paper extends and significantly modifies a recent open-source algorithm that solves SLAM problem using approach fundamentally different from a traditional approach. Proposed modifications provide the position measurements necessary for the navigation solution on a UAV. The main contributions of this work include: (1) extension of the map building algorithm to enable it to be used realistically while controlling a UAV and simultaneously building the map; (2) improved performance of the SLAM algorithm for lower camera frame rates; and (3) the first known demonstration of a monocular SLAM algorithm successfully controlling a UAV while simultaneously building the map. This work demonstrates that a fully autonomous UAV that uses monocular vision for navigation is feasible.

scholarly journals Feasibility analysis of uav in dengue control

2017 ◽  
Vol 8 (2) ◽  
pp. 319 ◽  
Author(s):  
Daiane Maria de Genaro Chiroli ◽  
Murillo Martins Montilha ◽  
Márcia Marcondes Altimari Samed
Keyword(s):  
Low Cost ◽  
Control Program ◽  
Feasibility Analysis ◽  
World Health ◽  
The World ◽  
Aerial Vehicle ◽  
Tropical Areas ◽  
Entire World ◽  
Dengue Control ◽  
Health Organization

There are intensifying actions to combat the mosquito Aedes which is admittedly responsible for the transmission of diseases: chikungunya, dengue and zika. Among these dengue is a recurring problem that affects the entire world, especially the tropical areas. It is considered one of the world’s greatest public health problems by the World Health Organization, which estimates that approximately 390 million people get infected by this disease each year worldwide. In Brazil, since the first report of the disease in 80’s, dengue has continually occurred, alternating epidemic periods with peaks of increasing disease. Therefore, this study aims to assess the feasibility of using unmanned aerial vehicle, popularly known as drone, in aid of the dengue control program executed in Maringá - PR. In conclusion the use of this aircraft is feasible, since it is an economically attractive investment due to its low cost against the annual investment with manpower.

Energy-Based Design of Reconfigurable Micro Aerial Vehicle (MAV) Flight Structures

2012 ◽  
Author(s):  
James Joo ◽  
Gregory Reich ◽  
James Elgersma ◽  
Kristopher Aber
Keyword(s):  
Micro Aerial Vehicle ◽  
Aerial Vehicle ◽  
Energy Based Design
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