AUV range-only localization and mapping: Observer design and experimental results

2013 ◽  
Author(s):  
Mohammadreza Bayat ◽  
A. Pedro Aguiar
Keyword(s):  
Observer Design ◽  
Experimental Results ◽  
Localization And Mapping

scholarly journals Estimation Error Based Disturbance Observer Design for Flexible Loop Shaping

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 358 ◽  
Author(s):  
Sangmin Suh
Keyword(s):  
Disturbance Observer ◽  
Closed Loop ◽  
Control Structure ◽  
Storage Systems ◽  
Estimation Error ◽  
Observer Design ◽  
Experimental Results ◽  
External Disturbances ◽  
Flexible Loop ◽  
Closed Loop Systems

This note presents an estimation error based disturbance observer (EEDOB) to reduce the effects of external disturbances. In the proposed control structure, a difference between an estimator output and a plant output is considered as an equivalent disturbance. Therefore, when a disturbance appears, the proposed disturbance observer (DOB) is activated. Unlike conventional DOB, this method does not require the plant inverse model or additional stabilizing filters. In addition, the proposed method always satisfies closed loop systems stability, which is definitely different from conventional DOB. To verify the effectiveness, this method was applied to commercial storage systems. From the experimental results, it is confirmed that tracking performance is improved by 23.5%.

Observer design for monocular visual inertial SLAM

2018 ◽  
Vol 66 (3) ◽  
pp. 246-257
Author(s):  
Geoff Fink ◽  
Mirko Franke ◽  
Alan F. Lynch ◽  
Klaus Röbenack
Keyword(s):  
Linear Time ◽  
Inertial Sensor ◽  
Vision System ◽  
Sufficient Conditions ◽  
Observer Design ◽  
State Transformation ◽  
Positioning Systems ◽  
Localization And Mapping ◽  
Global Positioning ◽  
Sufficient Conditions For Convergence

Abstract This paper examines the state estimation problem for unmanned aerial vehicles when commonly used positioning systems such as the global positioning system or indoor motion capture systems are unavailable. The proposed method uses inertial sensor measurements along with scaled position measurements from an onboard computer vision system which implements visual simultaneous localization and mapping. A state transformation puts the system into a linear time-varying form which simplifies observability analysis and allows for an observer design with sufficient conditions for convergence. The proposed design is validated by simulation.

On the Observability and the Observer Design of Differential Pneumatic Pistons

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Marco A. Arteaga-Pérez ◽  
Alejandro Gutiérrez-Giles ◽  
Jens Weist
Keyword(s):  
Observer Design ◽  
Experimental Results ◽  
System Model ◽  
Model Parameters ◽  
Proportional Integral ◽  
Design And Implementation ◽  
Observability Analysis

In this paper, an observability analysis for differential pneumatic pistons is presented, together with the design and implementation of linear observers of the Luenberger type. To avoid as much as possible the knowledge of the system model parameters, the generalized proportional integral (GPI) approach is employed for the estimation of unmeasured variables. Experimental results show the good performance of the proposed scheme.

scholarly journals An Improved Initialization Method for Monocular Visual-Inertial SLAM

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3063
Author(s):  
Jun Cheng ◽  
Liyan Zhang ◽  
Qihong Chen
Keyword(s):  
Iterative Method ◽  
Measurement Model ◽  
The Self ◽  
Experimental Results ◽  
Positioning Accuracy ◽  
Scale Estimation ◽  
Vision Measurement ◽  
Localization And Mapping ◽  
Initial Stage ◽  
Robot Platform

In the aim of improving the positioning accuracy of the monocular visual-inertial simultaneous localization and mapping (VI-SLAM) system, an improved initialization method with faster convergence is proposed. This approach is classified into three parts: Firstly, in the initial stage, the pure vision measurement model of ORB-SLAM is employed to make all the variables visible. Secondly, the frequency of the IMU and camera was aligned by IMU pre-integration technology. Thirdly, an improved iterative method is put forward for estimating the initial parameters of IMU faster. The estimation of IMU initial parameters is divided into several simpler sub-problems, containing direction refinement gravity estimation, gyroscope deviation estimation, accelerometer bias, and scale estimation. The experimental results on the self-built robot platform show that our method can up-regulate the initialization convergence speed, simultaneously improve the positioning accuracy of the entire VI-SLAM system.

scholarly journals An Improved Initialization Method for Monocular Visual-Inertial SLAM

2021 ◽  
Author(s):  
Cheng Jun ◽  
Zhang Liyan ◽  
Chen Qihong
Keyword(s):  
Iterative Method ◽  
Measurement Model ◽  
The Self ◽  
Experimental Results ◽  
Positioning Accuracy ◽  
Scale Estimation ◽  
Vision Measurement ◽  
Localization And Mapping ◽  
Initial Stage ◽  
Robot Platform

In the aim of improving the positioning accuracy of monocular visual inertial simultaneous localization and mapping (VI-SLAM) system, an improved initialization method with faster convergence is proposed. This approach is classified as three parts: Firstly, in the initial stage, the pure vision measurement model of ORB-SLAM is employed to make all the variables visible. Secondly, the frequency of IMU camera was aligned by IMU preintegration technology. Thirdly, an improved iterative method is put forward for estimating the initial parameters of IMU faster. The estimation of IMU initial parameters is divided into several simpler sub-problems, containing direction refinement gravity estimation, gyroscope deviation estimation, accelerometer bias and scale estimation. The experimental results on the self-built robot platform show that our method can up-regulate the initialization convergence speed, simultaneously improve the positioning accuracy of the entire VI-SLAM system.

Underwater localization and mapping: observability analysis and experimental results

2014 ◽  
Vol 41 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Mohammadreza Bayat ◽  
A. Pedro Aguiar
Keyword(s):  
Minimum Energy ◽  
Simultaneous Localization And Mapping ◽  
The Body ◽  
Experimental Results ◽  
Multiple Model ◽  
Content Type ◽  
Numerical Tests ◽  
Observability Analysis ◽  
Localization And Mapping ◽  
Theoretical Results

Purpose – The authors aim to investigate the observability properties of the process of simultaneous localization and mapping of an autonomous underwater vehicle (AUV), a challenging and important problem in marine robotics, and illustrate the derived results through computer simulations and experimental results with a real AUV. Design/methodology/approach – The authors address the single/multiple beacon observability analysis of the process of simultaneous localization and mapping of an AUV by deriving the nonlinear mathematical model that describes the process; then applying a suitable coordinate transformation, and subsequently a time-scaling transformation to obtain a linear time varying (LTV) system. The AUV considered is equipped with a set of inertial sensors, a depth sensor, and an acoustic ranging device that provides relative range measurements to a set of stationary beacons. The location of the beacons does not need to be necessarily known and in that case, the authors are also interested to localize them. Numerical tests and experimental results illustrate the derived theoretical results. Findings – The authors show that if either the position of one of the beacons or the initial position of the AUV is known, then the system is at least locally weakly observable, in the sense that the set of indistinguishable states from a given initial configuration contains a finite set of isolated points. The simulations and experiments results illustrate the findings. Originality/value – In the single and multiple beacon case and for manoeuvres with constant linear and angular velocities both expressed in the body-frame, known as trimming or steady-state trajectories, the authors derive conditions under which it is possible to infer the state of the resulting system (and in particular the position of the AUV). The authors also describe the implementation of an advanced continuous time constrained minimum energy observer combined with multiple model techniques. Numerical tests and experimental results illustrate the derived theoretical results.

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