arXiv subjects

Abdelhamid Tayebi

Publications and source records attributed to Abdelhamid Tayebi.

51 records · Page 3Linked to original sources

arXiv2020

Nonlinear State Estimation for Inertial Navigation Systems With Intermittent Measurements

This paper considers the problem of simultaneous estimation of the attitude, position and linear velocity for vehicles navigating in a three-dimensional space. We propose two types of hybrid nonlinear observers using continuous angular velocity and linear acceleration measurements as well as intermittent landmark position measurements. The first type relies on a fixed-gain design approach based on an infinite-dimensional optimization, while the second one relies on a variable-gain design approach based on a continuous-discrete Riccati equation. For each case, we provide two different observers with and without the estimation of the gravity vector. The proposed observers are shown to be exponentially stable with a large domain of attraction. Simulation and experimental results are presented to illustrate the performance of the proposed observers.

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arXiv2020

Hybrid Nonlinear Observers for Inertial Navigation Using Landmark Measurements

This paper considers the problem of attitude, position and linear velocity estimation for rigid body systems relying on landmark measurements. We propose two hybrid nonlinear observers on the matrix Lie group $SE_2(3)$, leading to global exponential stability. The first observer relies on fixed gains, while the second one uses variable gains depending on the solution of a continuous Riccati equation (CRE). These observers are then extended to handle biased angular velocity measurements. Both simulation and experimental results are presented to illustrate the performance of the proposed observers.

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arXiv2018

On the Design of Hybrid Pose and Velocity-bias Observers on Lie Group SE(3)

This paper deals with the design of globally exponentially stable invariant observers on the Special Euclidian group SE(3). First, we propose a generic hybrid observer scheme (depending on a generic potential function) evolving on $SE(3)\times \mathbb{R}^6$ for pose (orientation and position) and velocity-bias estimation. Thereafter, the proposed observer is formulated explicitly in terms of inertial vectors and landmark measurements. Interestingly, the proposed observer leads to a decoupled rotational error dynamics from the translational dynamics, which is an interesting feature in practical applications with noisy measurements and disturbances.

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arXiv2017

Attitude and Gyro Bias Estimation Using GPS and IMU Measurements

We propose an attitude and gyro-bias estimation scheme for accelerated rigid body systems using an inertial measurement unit (IMU) and a global positioning system (GPS). The proposed scheme allows to obtain attitude estimates directly on the Special Orthogonal group $SO(3)$ while estimating the gyro bias and the unknown apparent acceleration of the vehicle. We prove semi-global exponential stability of the estimation errors. Furthermore, a new switching technique for the attitude state is introduced which results in a velocity-aided hybrid attitude observer with proven global exponential stability.

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arXiv2017

On the Design of Attitude Observers on the Special Orthogonal Group $SO(3)$

We revisit the nonlinear complimentary filter on $SO(3)$, previously proposed in the literature, and provide the (time-explicit) solution to the matrix ODE governing the attitude estimation error in the absence of measurement errors. The stability and performance properties of this filter can be easily deduced from the obtained closed-from solution. Thereafter, we consider two nonlinear complimentary filters (with state-dependent gains) which are shown to exhibit improved stability and performance proprieties compared to the traditional filter. We perform robustness analysis for the three discussed attitude filters on $SO(3)$ with respect to attitude and angular velocity measurement errors. Specifically, we show that the state-dependent-gain filters may exhibit improved robustness to gyro measurement disturbances and a better disturbance attenuation levels. Simulation results are performed to confirm the obtained theoretical results.

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arXiv2017

On the Design of Globally Exponentially Stable Hybrid Attitude and Gyro-bias Observers

This paper presents hybrid attitude and gyro-bias observers designed directly on the Special Orthogonal group SO(3). The proposed hybrid observers, enjoying global exponential stability, rely on a hysteresis-based switching between different configurations derived from a set of potential functions on SO(3). Different sets of potential functions have been designed via an appropriate angular warping transformation applied to some smooth and non-smooth potential functions on SO(3). We show that the proposed hybrid observers can be expressed solely in terms of inertial vector measurements and biased angular velocity readings. Simulation results are given to illustrate the effectiveness of the proposed attitude estimation approach.

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arXiv2016

A Central Synergistic Hybrid Approach for Global Exponential Stabilization on SO(3)

We propose a new central synergistic hybrid approach for global exponential stabilization on the Special Orthogonal group SO(3). We introduce a new switching concept relying on a central family of (possibly) non-differentiable potential functions that enjoy (as well as their gradients) the following properties: 1) being quadratic with respect to the Euclidean attitude distance, and 2) being synergistic with respect to the gradient's singular and/or critical points. The proposed approach is used to solve the attitude tracking problem, leading to global exponential stability results.

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arXiv2016

A Globally Exponentially Stable Hybrid Attitude and Gyro-bias Observer

This paper presents a hybrid attitude and gyro-bias observer designed directly on the Special Orthogonal group SO(3). The proposed hybrid observer, relying on a hysteresis-based switching between two configurations, guarantees global exponential stability using biased angular velocity and inertial vector measurements. Simulation results are given to illustrate the effectiveness of the proposed observer.

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arXiv2016

On Deterministic Attitude Observers on the Special Orthogonal Group SO(3)

We revisit the gradient based nonlinear attitude complementary filters (observers) on the Special Orthogonal group SO(3) and provide explicit solutions of the norm of the attitude estimation error dynamics. One smooth and two non-smooth attitude observers are considered. The stability and performance properties of theses attitude observers can be easily deduced from the obtained explicit solutions. We show that the smooth complementary attitude filter, previously proposed in the literature, is not Input-to-State-Stable (ISS) with respect to bounded measurement disturbances while the non-smooth versions are. We also show that the non-smooth versions of the attitude complementary filter exhibit better convergence rates. Some simulations are provided to illustrate our results.

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arXiv2016

Global Exponential Angular Velocity Observer for Rigid Body Systems

We present a uniformly globally exponentially stable hybrid angular velocity observer for rigid body systems designed directly on $SO(3)\times\mathbb{R}^3$. The global exponential stability result makes this observer a good candidate for a controller-observer combination with a guaranteed separation property. Simulation results are provided to demonstrate the effectiveness of the proposed hybrid observer as a part of an attitude stabilization scheme.

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arXiv2016

Cooperative Output Regulation of Linear Multi-agent Systems with Communication Constraints

In this paper, we consider the cooperative output regulation problem for heterogeneous linear multi-agent systems in the presence of communication constraints. Under standard assumptions on the agents dynamics, we propose a distributed control algorithm relying on intermittent and asynchronous discrete-time information exchange that can be subject to unknown time-varying delays and information losses. We show that cooperative output regulation can be reached for arbitrary characteristics of the discrete-time communication process and under mild assumptions on the interconnection topology between agents. A numerical example is given to illustrate the effectiveness of our theoretical results.

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arXiv2016

Containment Control of Second-order Multi-agent Systems Under Directed Graphs and Communication Constraints

The distributed coordination problem of multi-agent systems is addressed in this paper under the assumption of intermittent communication between agents in the presence of time-varying communication delays. Specifically, we consider the containment control problem of second-order multi-agent systems with multiple dynamic leaders under a directed interconnection graph topology. Also, communication between agents is performed only at some discrete instants of time in the presence of irregular communication delays and packet dropout. First, we present distributed control algorithms for double integrator dynamics in the full and partial state feedback cases. Then, we propose a method to extend our results to second-order systems with locally Lipschitz nonlinear dynamics. In both cases, we show that the proposed approach leads to our control objectives under sufficient conditions relating the characteristics of the communication process and the control gains. We also show that our approach can be applied to solve various similar coordination problems in multi-agent systems under the same communication constraints. The effectiveness of the proposed control schemes is illustrated through some examples and numerical simulations.

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arXiv2016

Construction of Synergistic Potential Functions on SO(3) with Application to Velocity-Free Hybrid Attitude Stabilization

We propose a systematic and comprehensive procedure for the construction of synergistic potential functions, which are instrumental in hybrid control design on SO(3). A new map via angular warping on SO(3) is introduced for the construction of such a family of potential functions allowing an explicit determination of the critical points and the synergistic gap. Some optimization results on the synergistic gap are also provided. The proposed synergistic potential functions are used for the design of a global velocity-free hybrid attitude stabilization scheme relying solely on inertial vector measurements. Comparative simulation results between the proposed global hybrid control scheme and the almost global smooth control scheme have been carried out.

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arXiv2015

On the Synchronization of Second-Order Nonlinear Systems with Communication Constraints

This paper studies the synchronization problem of second-order nonlinear multi-agent systems with intermittent communication in the presence of irregular communication delays and possible information loss. The control objective is to steer all systems' positions to a common position with a prescribed desired velocity available to only some leaders. Based on the small-gain framework, we propose a synchronization scheme relying on an intermittent information exchange protocol in the presence of time delays and possible packet dropout. We show that our control objectives are achieved with a simple selection of the control gains provided that the directed graph, describing the interconnection between all systems (or agents), contains a spanning tree. The example of Euler-Lagrange systems is considered to illustrate the application and effectiveness of the proposed approach.

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arXiv2012

A New Position Control Strategy for VTOL UAVs using IMU and GPS measurements

We propose a new position control strategy for VTOL-UAVs using IMU and GPS measurements. Since there is no sensor that measures the attitude, our approach does not rely on the knowledge (or reconstruction) of the system orientation as usually done in the existing literature. Instead, IMU and GPS measurements are directly incorporated in the control law. An important feature of the proposed strategy, is that the accelerometer is used to measure the apparent acceleration of the vehicle, as opposed to only measuring the gravity vector, which would otherwise lead to unexpected performance when the vehicle is accelerating (i.e. not in a hover configuration). Simulation results are provided to demonstrate the performance of the proposed position control strategy in the presence of noise and disturbances.

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