Nacim Ramdani

Nacim Ramdani
Université d'Orléans | UO · Laboratoire PRISME

PhD, Eng.

About

150
Publications
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1,484
Citations

Publications

Publications (150)
Article
This work introduces a new approach based on an event‐triggered mechanism (ETM) to design finite‐gain interval observers for linear continuous‐time systems in the presence of unknown‐but‐bounded uncertainties with a priori known bounds on state disturbances and measurement noises. In this setting, aperiodic measurements sampling is controlled in a...
Article
This paper addresses the modeling and the design of an interval state observer for a linear time-invariant plant in presence of sporadically available measurements corrupted by unknown-but-bounded errors and noise. The interval observer is modelled as an impulsive system where an impulsive correction is made whenever a measurement is available. The...
Article
Full-text available
As an integral part of patient care, nursing is required to constantly adapt to changes in the healthcare system, as well as the wider financial and societal environment. Among the key factors driving these changes is the aging of population. Combined with an existing shortage of nursing and caregiving professionals, accommodating for the patients...
Article
Ambient Assisted Living (AAL) aims to ease the activities of daily lives for elderly or disabled people living in smart homes. In these systems, the assisting services are provided by use of the sensors that detect the location of inhabitants. Even though the cost and performance efficiencies of sensor networks depend directly on the number of the...
Article
Full-text available
This article proposes a robust tracking controller for an underactuated quadrotor model based on the flatness theory and Active Disturbance Rejection Control (ADRC). Exploiting the differential flatness characteristic, it is demonstrated that a nonlinear quadrotor system can be changed into a linear canonical form, where it is easier to create a st...
Article
This work suggests flatness-based Active Disturbance Rejection Control (ADRC) to deal with the problem of trajectory tracking for Wheeled Mobile Robot (WMR). Based on the differential flatness theory, the nonlinear WMR system is transformed into two integral-chains, which makes the creation of a state feedback controller easier. In order to improve...
Article
This paper proposes a box expanding method to reduce the economic dispatch (ED) cost in the box-based robust unit commitment model (BUC). As a non-anticipative robust unit commitment model for a power system under demand uncertainty, BUC co-optimizes the commitment schedule and the feasible set of the ED problem to minimize the total operating cost...
Article
To design robust interval observers for uncertain continuous‐time linear systems, a new set‐integration approach is proposed to compute trajectory tubes for the estimation error. Because this approach, the order‐preserving condition on the dynamics of the estimation error is no longer required. Therefore, synthesis methods can be used to compute ob...
Conference Paper
Full-text available
The deployment of autonomous robots/vehicles is increasing in several domains. To perform tasks properly, a robot must have a good perception about its environment while detecting dynamic obstacles. Recently, evidential grids have attracted more interest for environment perception since they permit more effective uncertainty handling. The latest st...
Article
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Hospitals are considered a field of logistic robotics of high commercial potential and therefore a handful of mobile robot solutions exist. However, they have failed to trigger widespread acceptance by the market. The ENDORSE system will pursue 4 innovation pillars: an infrastructure-less multi-robot navigation, i.e. minimum installation of sensors...
Article
This letter focuses on a day-ahead scheduling problem on thermal power plants and storage batteries based on the information of the interval prediction of photovoltaic (PV) power and demand. To realize an optimal operation, there are three kinds of decision variables to plan, which correspond to a generating power schedule, a charge/discharge (C/D)...
Article
The paper introduces a method for synthesising set-valued state estimators for uncertain discrete-time linear systems. Based on the past values of the input and output of the system and on its observability matrix, a non-conservative numerical scheme is proposed to characterise at each time instant a tight enclosure of the actual state vector of th...
Article
Pyro-electric Infra Red (PIR) sensors have been widely used in different indoor localization applications during the last decade. These sensors are cheap, non-intrusive and nonwearable, nevertheless, the binary PIR sensor detects only the presence of a human motion in its field of view without any other information about the actual location. Theref...
Article
This work proposes an optimal trajectory generation and a robust flatness–based tracking controller design to create a new performance guidance module for the quadrotor in dense indoor environments. The properties of the differential flatness, the B‐spline, and the direct collocation method are exploited to convert the constrained optimization prob...
Article
Full-text available
This work proposes guaranteed trajectory tracking control for a quadrotor based on feedforward flatness control and an interval observer. Using the exact feedforward linearization based on the differential flatness property, it is proven that the nonlinear quadrotor model can be transformed into the linear canonical system for which it is easier to...
Article
This paper focuses on the day-ahead scheduling problem of generating power for thermal power plants and charging/discharging battery energy storage systems based on interval predictions of photovoltaic power. Our previous approach to this problem used the Jacobian of a solution with respect to the variation in demand. However, this study was limite...
Article
State estimation is a key engineering problem when addressing control or diagnosis issues for complex dynamical systems. The issue is still challenging when the latter systems must be modelled as hybrid discrete–continuous dynamics, which is true for many complex and safety-critical systems. In this paper, we investigate nonlinear hybrid state esti...
Article
This study proposes an efficient and automatic tool to understand and analyze the human natural and fast gait tasks. First, the gait tasks are modeled as a nonlinear optimal control problem along with a nonlinear model predictive control, usually used in the humanoid robots control. Second, under the assumption that the walking motions are the resu...
Article
This paper deals with the problem of state estimation for linear continuous-time systems based on the prediction-correction (PC) set-membership approach. Although the abundant literature on using the PC estimation approach, the case of event-based measurement sampling is still poorly investigated. In the developed approach, the measurement in the c...
Article
This paper studies a day-ahead scheduling problem on power generation of thermal power plants and charge/discharge of battery energy storage systems, where the confidence intervals of the prediction of photovoltaic (PV) and demand power are available. This problem is reduced to an interval optimization problem, where parameters having any values in...
Article
In this study, we aim to recover the interval hull of the set of feasible cost functions that can make uncertain observations optimal for a class of nonlinear constrained parametric optimization problems when all uncertainty and disturbances acting on observations or modeling are taken bounded but otherwise unknown. Fostering on inverse Karush-Kuhn...
Article
In this paper, a passive method for robust fault detection and isolation is elaborated in the context of set-membership approach. The basic idea behind the proposed method is to compute a feasible set containing the states of a nonlinear system states using an interval constraints propagation method. A consistency test is performed using the q-rela...
Article
Hybrid systems exhibit continuous and discrete dynamics and are encountered in many complex and safety-critical systems. Due to their complex nature, the fault diagnosis task becomes very challenging. In this paper, we present a method to perform fault detection with a nonlinear hybrid system using set-membership parameter estimation in a bounded-e...
Article
Full-text available
In this paper, we propose an interval quadratic programming method for the day-ahead scheduling of power generation and battery charge cycles, where the prediction uncertainty of power consumption and photovoltaic power generation is described as a parameter vector lying in an interval box. The interval quadratic programming is formulated as the pr...
Article
Reachability analysis of nonlinear uncertain hybrid systems, i.e., continuous-discrete dynamical systems whose continuous dynamics, guard sets and reset functions are defined by nonlinear functions, can be decomposed in three algorithmic steps: computing the reachable set when the system is in a given operation mode, computing the discrete transiti...
Article
Full-text available
The use of smart homes has been increasing greatly in recent years thanks to considerable achievements in technology. Home automation aims to improve person's autonomy and safety. For that reason, many indoor localization systems were developed recently. Nevertheless, their efficiency were improved for a single inhabitant and can not be applied in...
Conference Paper
Full-text available
Within the framework of demographic changes and the constraint of permanent growth of the elderly number in European population (i.e. France) which the health sector is confronted to, the detection of abnormal behaviors in the supervisory framework has known a particular interest during these last years. Thereby, the main objective of this paper is...
Article
A set-membership (SM) approach is proposed to design reliable static stabilizing controllers for non-linear dynamical systems. First, the control design problem is reformulated as a parameter identification issue in an unknown-but-bounded error framework. Then, a new dual set integration method for reachability computation is introduced. Finally, t...
Conference Paper
In this paper, we apply inverse optimal control approaches in order to recover the cost function that can explain given observations, for a class of constrained optimization problems. The inverse optimal control was recently solved in an approximately optimal framework, meaning that the interest is in finding the proper criteria suitable for the sy...
Conference Paper
Large-scale penetration of photovoltaic (PV) power generators and storage batteries is expected into the power system in Japan. To maintain the supply-demand balance with energy storage, the optimal power generation and the charge/discharge power of storage batteries can be determined in a manner of the model predictive control of generators. In vi...
Article
Home automation is now implemented in many retirement homes in order to improve elderly's autonomy and safety. Smart homes allow to monitor the activities of elderly persons using information coming from different sensors. The ADL (Activities of Daily Living) are used to evaluate the ability of a person to perform on their own a selection of the ac...
Article
This paper deals with the general problem of the estimation of physical parameters in the presence of nuisance parameters for which an explicit characterisation of the uncertainty is available. Within a bayesian context, the maximum a posteriori estimation is used. The asymptotic confidence ellipsoid is then determined. The projection of the latter...
Article
Full-text available
This paper investigated the possibility of estimating 3D lower limb joint kinematics during five popular rehabilitation exercises of the hip and knee joints based on the data collected from a single inertial measurement unit located on the shank. The leg was modeled as a four-degree-of-freedom serial chain, and the relevant joint angles were repres...
Article
Computing the reachable set of hybrid dynamical systems in a reliable and verified way is an important step when addressing verification or synthesis tasks. This issue is still challenging for uncertain nonlinear hybrid dynamical systems. We show in this paper how to combine a method for computing continuous transitions via interval Taylor methods...
Article
The concern with renewable energy has been growing. Large-scale installation of photovoltaic (PV) generation and electricity storage is expected to be installed into the power system in Japan. In this situation, we need to keep supply-demand balance by systematically using not only traditional power generation systems but also the PV generation and...
Conference Paper
The concern with renewable energy has been growing. Large-scale installation of photovoltaic (PV) generation and electricity storage is expected to be installed into the power system in Japan. In this situation, we need to keep supply-demand balance by systematically using not only traditional power generation systems but also the PV generation and...
Conference Paper
The computation of reachable sets for hybrid systems with nonlinear continuous dynamics is addressed. In this context, the computation of the intersection of the reachable set with the guard set is a challenging problem. In a previous work, we have proposed a guaranteed relaxation method expressed as a constraint satisfaction problem to solve the e...
Conference Paper
In this paper, a method for computing reachable sets of uncertain nonlinear continuous-time systems is proposed. The approach, based on Linear Parameter-Varying (LPV) inclusions of nonlinear systems, relies on a time-varying change of coordinates which ensures some monotony properties in the new base. A sufficient condition ensuring the non diverge...
Conference Paper
Reachability computation formulates the problem of simulating the behavior of a continuous or hybrid dynamical system in a set-theoretical framework. Compared to the stochastic approach, it provides guaranteed results and has been shown highly valuable for verification or synthesis tasks. This issue is still quite challenging for uncertain nonlinea...
Conference Paper
In this study, we endeavor to better understand the human motor control system in order to help transposing some of its features onto humanoid robots. The postural coordination task investigated is related to an experimental paradigm that consists in visual target tracking task while balancing. We want to test whether the human biomechanical respon...
Article
Full-text available
Set membership estimation (SME) of nonlinear hybrid systems is still a challenging issue. Although SME of nonlinear continuous systems has made significant progress recently, the direct extension of these methods to the hybrid case is not easy. Meanwhile, satisfiability (SAT) checkers for Boolean combinations of arithmetic constraints over real-and...
Article
Résumé Les systèmes dynamiques hybrides sont des systèmes complexes où coexistent des dynamiques continues et événementielles. Ce sont souvent des systèmes embarqués ou cyber-physiques critiques. Lorsque les dynamiques mises en jeu sont non linéaires ou incertaines, la vérification et synthèse des lois de commande robustes pour ces systèmes, et l'e...
Conference Paper
Full-text available
A hierarchical state bounding estimation method is presented for nonlinear dynamic systems where different sensors offer several measurements of the same state vector, each of which is subject to unknown but bounded disturbances and is equipped with a local processor. For each sampling time, the proposed algorithm proceeds in two stages. At the pre...
Article
Full-text available
This paper introduces effective numerical methods for the planning and fast replanning of safe motions to ensure the safety, balance, and integrity of humanoid robots over the whole motion duration. Our safe methods do not depend on, nor are connected to, any type of modeling or constraints. To plan safe motions, certain constraints have to be sati...
Conference Paper
Full-text available
Aiming at automatic verification and analysis techniques for hybrid discrete-continuous systems, we present a novel combination of enclosure methods for ordinary differential equations (ODEs) with the iSAT solver for large Boolean combinations of arithmetic constraints. Improving on our previous work, the contribution of this paper lies in combinin...
Article
A hierarchical state bounding estimation method is presented for a nonlinear dynamic system where different sensors offer several potentially faulty measurements of the same state vector, each of which is subject to unknown but bounded disturbances and is equipped with a local processor. The proposed algorithm works at two levels : at each sampling...
Article
Full-text available
Optimal motions are usually used as joint refer- ence trajectories for repetitive o rc omplex motions. In th ec ase of soccer robots, the kicking motion is usuall ya benchmark motion, computed off-line, withou tt aking int oa ccoun tt he current position o ft h er obot or the direction o ft he goal. Moreover, robots must react quickly t oa ny situa...
Article
This paper proposes a closed-loop optimal control model predicting changes between in-phase and anti-phase postural coordination during standing and related supra-postural activities. The model allows the evaluation of the influence of body dynamics and balance constraints onto the adoption of postural coordination. This model minimizes the instant...
Article
We investigate solution techniques for numerical constraint-satisfaction problems and validated numerical set integration methods for computing reachable sets of nonlinear hybrid dynamical systems in the presence of uncertainty. To use interval simulation tools with higher-dimensional hybrid systems, while assuming large domains for either initial...
Article
In this paper we design an interval observer for nonlinear uncertain continuous-time dynamical systems, in the unknown-but-bounded error framework. We show how to generate two coupled hybrid observers, which yield the best conservative upper and lower component-wise bounds for the state, provided bounds are available for initial conditions and unce...
Article
Full-text available
The estimation of the centre of mass position in humans is usually based on biomechanical models developed from anthropometric tables. This method can potentially introduce errors in studies involving elderly people, since the ageing process is typically associated with a modification of the distribution of the body mass. In this paper, an alternat...
Article
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This paper investigates guaranteed methods for estimating feasible parameter sets when the system under study is modelled with ordinary differential equations (ODE). The issue is to find the set of parameters such that the solution of the ODE remains within specified intervals at known time-data points. These intervals correspond usually to measure...
Article
We address nonlinear reachability computation for uncertain monotone systems, those for which flows preserve a suitable partial orderings on initial conditions. In a previous work Ramdani (2008) [22], we introduced a nonlinear hybridization approach to nonlinear continuous reachability computation. By analysing the signs of off-diagonal elements of...
Article
This paper deals with set-membership state estimation for continuous-time systems from discrete-time measurements, in the unknown but bounded error framework. The classical predictor–corrector approach to state estimation uses interval Taylor methods for solving the prediction phase, which are known to have poor performance in presence of large mod...
Conference Paper
Full-text available
A closed-loop model with actuator dynamics and sensory feedback has been developed to capture the complex postural behaviors observed in a human head tracking task. In motor-control literature, spindle feedback gains are scaled by the central nervous system to adapt muscle stiffness depending on the postural task. We propose to identify spindle ref...
Article
Full-text available
In this paper, we show how to compute an over-approximation for the reachable set of uncertain nonlinear continuous dynamical systems by using guaranteed set integration. We introduce two ways to do so. The first one is a full interval method which handles whole domains for set computation and relies on state-of-the-art validated numerical integrat...