G.V. Raffo

G.V. Raffo
Federal University of Minas Gerais | UFMG · Departamento de Engenharia Eletrônica (DELT)

PhD

About

110
Publications
14,054
Reads
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2,029
Citations
Citations since 2016
72 Research Items
1605 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300

Publications

Publications (110)
Article
Explicit Model Predictive Control (eMPC) aims to overcome the runtime computational effort from Model Predictive Control (MPC) by computing offline the overall optimization procedure. The result from eMPC is a Piecewise Affine (PWA) function that defines a relationship between the system state and the optimal control action. To improve the PWA eval...
Article
State estimators based on zonotopes have been receiving increased attention in the last years. Zonotopes are special polytopes that offer great computational advantages over well-known alternative representations as vertex and halfspace. In state estimation, zonotopes are challenged to execute a series of operations that influence both the precisio...
Article
State estimation in water distribution networks (WDNs) is a challenging task due to the scarcity of measurements and the presence of several modeling uncertainties. In the literature, pseudo-measurements are often required to obtain an observable model for state estimation, which are highly uncertain and mostly represented by bounded sets. This art...
Conference Paper
Full-text available
The ability to hide sensitive information is important in many contexts such as multi-agent systems' communications , industry 4.0, among others. In this paper, we deal with weak versions of known state-based opacity properties by using synchronizing automata to enforce such properties. A case study is presented in the context of the communication...
Conference Paper
Full-text available
A robust adaptive mixing controller (RAMC) is designed to solve the trajectory tracking problem of a quad-tiltrotor convertible plane (CP) unmanned aerial vehicle (UAV). This kind of system is a hybrid aerial vehicle that combines advantages of rotary and fixed-wing aircraft. In this work, the equations of motion of this UAV are obtained using the...
Article
This paper presents new methods for set-valued state estimation of discrete-time nonlinear systems whose trajectories are known to satisfy nonlinear equality constraints, called invariants (e.g., conservation laws). Set-valued estimation aims to compute tight enclosures of the possible system states in each time step subject to unknown-but-bounded...
Conference Paper
This work proposes a single-layer finite-horizon optimal control strategy to solve the autonomous navigation problem while accounting for energy efficiency and providing obstacle avoidance feature in cluttered environments with unknown obstacles. Considering the rate capacity effect of electric batteries, the nonlinear state-of-charge behavior is d...
Article
Full-text available
In the control systems community, path-following refers to the problem of tracking an output reference curve. This work presents a novel model predictive path-following control formulation for nonlinear systems with constraints, extended with an obstacle avoidance strategy. The method proposed in this work simultaneously provides an optimizing solu...
Article
This paper proposes new robust nonlinear optimal control formulations in the weighted Sobolev space, here called nonlinear W2 and W∞ controllers, to handle with two classes of underactuated mechanical systems: the reduced ones with a reduced number of DOF; and the entire underactuated mechanical systems with input coupling. The optimal control prob...
Article
Full-text available
Applications involving Unmanned Aerial Vehicles (UAVs) have increasingly required faster and more accurate movements to reduce flight time and to improve efficiency in the obstacle avoidance capability. In this context, this work proposes a nonlinear model predictive control (NMPC) strategy formulated on the Special Euclidean group SE(3) for quadro...
Article
Battery management systems (BMSs) are responsible for controlling and monitoring battery operations. In order to be effective, BMSs rely on mathematical models. The parameters of these latter are usually obtained through an identification procedure which provides limited accuracy. In addition, only cell current and voltage are usually measurable. F...
Conference Paper
This work proposes a xed-wing UAV (Ummaned Aerial Vehicle) control strategy based on feedback-linearization and model predictive control (MPC). The strategy makes use of the relationship between the applied control inputs of the UAV and the generalized forces and moments actuating on it. A linear model is obtained by the exact feedback-linearizatio...
Conference Paper
Full-text available
This paper deals with the trajectory tracking problem of a tilt-rotor unmanned aerial vehicle carrying a suspended load. An explicit model predictive control (eMPC) based on multiparametric optimization is used to derive optimal control laws which could be implemented in an embedded system. The eMPC is designed based on the nominal linearized error...
Conference Paper
This work presents two control strategies based on a classic nonlinear H infinity controller and on a novel nonlinear W infinity controller for robust trajectory tracking of an unmanned aerial manipulator (UAM). The controllers are implemented in a hardware-in-the-loop (HIL) framework using the ProVANT simulator, which was developed on the Gazebo a...
Conference Paper
Full-text available
This paper proposes a novel state estimator for discrete-time linear systems with Gaussian noise. The proposed algorithm is a fixed-gain filter, whose observer structure is more general than Kalman one for linear time-invariant systems. Therefore, the steady-state variance of the estimation error is minimized. For white noise stochastic processes,...
Presentation
Full-text available
In this presentation, a fixed-gain state estimator is derived based on H2 norm and steady-state variance. Its structure is more general than the Kalman one, since further matrices are introduced. We highlight that the proposed algorithm may lead the steady-state variance to smaller values than the stationary-gain Kalman estimators. Moreover, the n...
Article
A new robust adaptive mixing control (RAMC) is proposed in order to accomplish trajectory tracking of a tilt-rotor unmanned aerial vehicle (UAV) configuration. This kind of system is a hybrid aerial vehicle that combines advantages of rotary-wing aircraft, like hovering flight and vertical take-off and landing (VTOL), and those of fixed-wing aircra...
Preprint
This paper presents new methods for set-valued state estimation and active fault diagnosis of linear descriptor systems. The algorithms are based on constrained zonotopes, a generalization of zonotopes capable of describing strongly asymmetric convex sets, while retaining the computational advantages of zonotopes. Additionally, unlike other set rep...
Article
This paper presents new methods for set-valued state estimation of nonlinear discrete-time systems with unknown-but-bounded uncertainties. A single time step involves propagating an enclosure of the system states through the nonlinear dynamics (prediction), and then enclosing the intersection of this set with a bounded-error measurement (update). W...
Article
This paper presents new methods for set-valued state estimation and active fault diagnosis of linear descriptor systems. The algorithms are based on constrained zonotopes, a generalization of zonotopes capable of describing strongly asymmetric convex sets, while retaining the computational advantages of zonotopes. Additionally, unlike other set rep...
Article
This work proposes a guidance strategy of multiple robots to converge and circulate a curve while avoiding collisions by using a distributed model predictive control. To build the model predictive control framework, systems guided by control laws with parameters are considered, which laws are embedded in the optimization problem. After that, the sa...
Conference Paper
Full-text available
This work presents a Nonlinear Model Predictive Control strategy for a quadrotor UAV with obstacle avoidance capability in a 3D unknown environment with static obstacles. The system aims to reach the target in minimum time while avoiding obstacles and also to take into account the energy of states and inputs. Sensor information is processed to dete...
Conference Paper
Full-text available
This work presents a Nonlinear Model Predictive Control strategy for mobile robot navigation in unknown environments. The control system aims to reach a goal safely, as fast as possible, minimizing the control effort, and the distance between the current trajectory and the goal. A LIDAR (Light Detection and Ranging) sensor is used to obtain obstacl...
Poster
Full-text available
Filters are more accurate than predictors, but they demand zero time to acquire and process the current measurement data.
Conference Paper
Full-text available
In the literature, the state estimator for linear systems called zonotopic and Gaussian Kalman estimator was introduced by Combastel in 2015. It was proposed as a predictor and presented in the one-step form. The difference between a predictor and a filter is the measurement sequence used to estimate states. Predictors use the past measurements, wh...
Preprint
Full-text available
This paper presents new methods for set-valued state estimation of nonlinear discrete-time systems with unknown-but-bounded uncertainties. A single time step involves propagating an enclosure of the system states through the nonlinear dynamics (prediction), and then enclosing the intersection of this set with a bounded-error measurement (update). W...
Conference Paper
This paper proposes a hybrid structure for autonomous navigation of multiple robots with tasks assigned by a centralized scheduler. Considering the robots as Discrete Event Systems (DES), the Supervisory Control Theory (SCT) is used to model and control individually the behavior of each robot of the system. Particularly, gathering deliberative and...
Article
This work addresses the problem of path tracking control of a suspended load using a tilt-rotor UAV. The main challenge in controlling this kind of system arises from the dynamic behavior imposed by the load, which is usually coupled to the UAV by means of a rope, adding unactuated degrees of freedom to the whole system. Furthermore, to perform the...
Preprint
Full-text available
This work addresses the problem of path tracking control of a suspended load using a tilt-rotor UAV. The main challenge in controlling this kind of system arises from the dynamic behavior imposed by the load, which is usually coupled to the UAV by means of a rope, adding unactuated degrees of freedom to the whole system. Furthermore, to perform the...
Conference Paper
Full-text available
This paper presents a comparative review on the well-known stochastic and zonotopic filtering methods in the literature for state estimation of uncertain nonlinear systems. To achieve that, a unified notation for both approaches is proposed. While the unscented Kalman filter provides a suboptimal estimate for the mean based on the minimum-variance...
Conference Paper
Full-text available
This paper presents a comparative review on the most usual stochastic and zonotopic filtering methods in the literature for state estimation of uncertain linear systems. The mean and the confidence level of the Gaussian random variable are compared to the center and uncertainty of the zonotopic variable. To achieve that, a unified notation for thes...
Thesis
Full-text available
Since 1960, with the proposition of the Kalman filter (KF), the problem of state estimation has owned relevance in the literature. KF and its derivations are well known solutions to estimate states for both linear and nonlinear systems. The essence of the KF is to treat the variables of the system as random variables (VA) with Gaussian probability...
Article
Full-text available
This paper proposes a nonlinear control strategy to solve the trajectory tracking problem of a tilt-rotor Unmanned Aerial Vehicle (UAV) when transporting a suspended load. For the present study, the aim of the control system is to track a desired trajectory of the aircraft with load’s swing-free, even in the presence of external disturbances, param...
Article
This paper presents a singular perturbation control strategy for regulating both the longitudinal and the lateral-directional flight dynamics of an Unmanned Aerial Vehicle (UAV). The proposed control strategy is based on a double four-time-scale (4TS) decomposition of the longitudinal and lateral-directional dynamics. The longitudinal dynamics incl...
Article
This paper presents a two-stage cascade control framework to solve hierarchically the trajectory tracking problem of a Tilt-rotor Unmanned Aerial Vehicle (UAV) carrying a suspended load. Initially, a nonlinear dynamic model is presented, which is after decoupled into two subsystems. The outer control system is designed by means of a robust tube-bas...
Article
Two important paradigms in control theory are the classic nonlinear H2 and H∞ control approaches. Their background theory are well developed, and several applications have demonstrated their efficiency. Despite many advantages, they suffer from deficiencies such as minimum settling-time and minimum overshoot. An interesting approach to solve these...
Article
Full-text available
This work proposes a control strategy to solve the path tracking problem of a suspended load carried by a tilt-rotor unmanned aerial vehicle (UAV). Initially, the equations of motion for the multibody mechanical system are derived from the load’s perspective by means of the Euler-Lagrange formulation, in which the load’s position and orientation ar...
Article
Full-text available
The paper proposes a new nonlinear H-infinity control method for multi-DOF robotic manipulators. At first stage local linearization of the robotic model is performed round its present operating point. The approximation error that is introduced to the linearized model due to truncation of higher-order terms in the performed Taylor series expansion i...
Article
The problem of control and navigation for autonomous underwater vessels (AUVs) is solved using differential flatness theory and the Derivative-free nonlinear Kalman Filter. First, differential flatness is proven for the 6-DOF dynamic model of the AUV. This allows for transforming the AUV model into the linear canonical (Brunovsky) form and for desi...
Article
The paper proposes a new nonlinear H-infinity control method for multi-DOF robotic manipulators. At first stage local linearization of the robotic model is performed round its present operating point. The approximation error that is introduced to the linearized model due to truncation of higher-order terms in the performed Taylor series expansion i...
Article
Full-text available
Cyber-physical systems (CPSs) consist of complex systems that use an embedded computing system, typically network connected, to control an electro-mechanical device. An Unmanned Aerial Vehicle (UAV) is a typical example of a CPS. In this paper authors present a model-driven design method devoted for the development of UAVs. Such method should be us...
Article
This paper deals with the load transportation problem by a tilt-rotor unmanned aerial vehicle. Most approaches address the subject by formulating the system dynamics from the UAV's point of view, with the load's behavior described with respect to it. Difficulties arise if control tasks are given for the load, since the suspended load coordinates do...
Conference Paper
This work addresses the problem of load transportation by a tilt-rotor unmanned aerial vehicle (UAV). In the literature, the suspended load's dynamics are often regarded as external disturbances affecting the UAV, or are handled implicitly in the equations of motion of the system, not allowing direct control of its coordinates. This work presents t...
Conference Paper
This work presents the modeling and control of a tilt-rotor UAV, with tail controlled surfaces, for path tracking with improved forward flight. The dynamic model is obtained using the Euler-Lagrange formulation considering the aerodynamic forces and torques exerted on the horizontal and vertical stabilizers, and fuselage. For control design purpose...
Conference Paper
Full-text available
The model-free strategy called Active Disturbance Rejection Control (ADRC) is applied to the pitch attitude control of a Twin-Rotor system. The original ADRC strategy is modified to account for the quantization of system's pitch angle associated with the use of an incremental encoder. The modifications include the use of Algebraic Differentiator to...
Conference Paper
Full-text available
This work describes the modeling and control of a tilt-rotor UAV with tail controlled surfaces for path tracking with improved forward velocity. The dynamic model is obtained using the Euler-Lagrange formulation. Mixed H2 /H-Infinity controllers are designed for different operation points, whose feedback gains are interpolated by a neural network f...
Conference Paper
Full-text available
This paper proposes an adaptive control strategy to solve the path tracking problem of a Tilt-rotor UAV in load transportation tasks. Initially, a nonlinear dynamic model is obtained through the Euler-Lagrange formulation and linearized around a reference trajectory in order to obtain a linear parameter-varying model. Therefore, a discrete linear a...
Conference Paper
Full-text available
In this paper a model predictive control (MPC) is used to solve the path tracking problem of a tilt-rotor unmanned aerial vehicle while it carries a suspended load. The MPC is designed based on the linear error model of the system, which is linearized around a generic trajectory. The control action is calculated via an optimization problem, where a...
Article
This paper proposes a cascade nonlinear control strategy to solve the problem of balancing an inverted pendulum using a Tilt-rotor Unmanned Aerial Vehicle while tracking a desired position reference. For the present study, the aim is to maintain both the aircraft and the pendulum stable throughout the whole trajectory, even in the presence of param...
Article
The application of two guaranteed estimation methods on the estimation of a quadrotor position is presented in this paper. A discrete time system model used for the position estimation is supposed, whereas GPS measurement is performed with greater sampling time. Firstly, guaranteed algorithms are applied in order to compute the feasible set of posi...
Article
This paper proposes a nonlinear control strategy to solve the suspended load transportation problem using a Tilt-rotor Unmanned Aerial Vehicle. The aim is to maintain both the aircraft and the load stable throughout the whole trajectory, even in the presence of parametric uncertainties and measurement errors. The system modeling is obtained via Eul...
Article
Full-text available
This paper proposes an approach for the robust stabilization of systems controlled by MPC strategies. Uncertain SISO linear systems with box-bounded parametric uncertainties are considered. The proposed approach delivers some constraints on the control inputs which impose sufficient conditions for the convergence of the system output. These stabili...
Article
A nonlinear H∞ controller is designed and applied for two-wheeled self-balanced vehicles, which are underactuated mechanical systems with input coupling. The main objective is, in the presence of exogenous disturbances, to ensure that the inclination angle of the pendulum (controlled DOF) is led to the upper vertical position, while the angular vel...
Conference Paper
Full-text available
In this paper a model predictive control is used to solve the path tracking problem of a tiltrotor unmanned aerial vehicle. The MPC controller is based on the linear error model of a tilt-rotor and the linearization is performed around a generic trajectory. The non-linear system is obtained via Euler-Lagrange formulation, taking into account eight...
Conference Paper
Over the last years the development of Unmanned Aerial Vehicles (UAVs) has attracted interest both from academia and industry. The use of these aircrafts in the agribusiness has presented positive results, both in precision agriculture applications and in plantations monitoring, by the data collection of the Wireless Sensor Network (WSN) used in th...
Article
Full-text available
Intelligence and autonomy is becoming a prerequisite for maritime transportation systems. In this paper a distributed control problem for unmanned surface vessels (USVs) is formulated as follows: there are N USVs which pursue another vessel (moving target). Each USV can be equipped with various sensors, such as IMU, cameras and non-imaging sensors...
Article
The paper proposes a nonlinear control approach for the underactuated hovercraft model based on differential flatness theory and uses a new nonlinear state vector and disturbances estimation method under the name of derivative-free nonlinear Kalman filter. It is proven that the nonlinear model of the hovercraft is a differentially flat one. It is s...
Article
In this paper a nonlinear robust control strategy designed for underactuated mechanical systems is proposed in order to solve the path tracking problem for a quadrotor unmanned aerial vehicle. An underactuated nonlinear H∞ controller based on the six degrees of freedom dynamic model is designed to control the helicopter attitude and altitude in the...
Article
This paper deals with the application of nonlinear H∞ control techniques to a underactuted mechanical system, which is named as PPCar. A comparison between two nonlinear H∞ control strategies is presented. The first one considers only the position and velocity errors in the cost vector. In the second one the integral position error is added with th...
Conference Paper
The paper proposes adaptive fuzzy control based on differential flatness theory for autonomous submarines. It is proven that the dynamic model of the submarine, having as state variables the vessel’s depth and its pitch angle, is a differentially flat one. This means that all its state variables and its control inputs can be written as differential...
Conference Paper
In this paper a distributed control problem for unmanned surface vessels (USVs) is formulated as follows: there are N USVs which pursue another vessel (moving target). At each time instant each USV can obtain measurements of the target’s cartesian coordinates. The objective is to make the USVs converge in a synchronized manner towards the target, w...
Conference Paper
This paper describes RBESP, a dual stack protocol designed as part of the communication infrastructure of a short-range Unmanned Aerial Vehicle (UAV). It aims at providing a reliable communication between the UAV and its base station and a best effort communication between the UAV and a WSN. RBESP targets two distinct communication requirements usi...
Conference Paper
This paper presents a dead-time compensation strategy to control constrained nonlinear systems with single-input delay by using a dead-time free model. Prediction error and disturbance effects are analyzed in order to guarantee input-to-state stability (ISS) and robust constraint satisfaction in the presence of bounded disturbances. It is shown rob...
Conference Paper
This paper describes a low cost wireless communication infrastructure designed for a short-range Unmanned Aerial Vehicle (UAV). It aims at providing a communication link between the UAV and a base station and also additional links that may allow collecting data from a remote Wireless Sensor Network (WSN). The challenge here is using the same hardwa...
Article
This paper presents a predictive and nonlinear robust control strategy to solve the path tracking problem for a quadrotor helicopter. The dynamic motion equations are obtained by the Lagrange-Euler formalism. The control structure is performed through a model-based predictive controller (MPC) to track the reference trajectory and a nonlinear H ∞ co...
Article
This work presents an IDA-PBC control methodology for a quadrotor helicopter to perform path tracking. The control law is designed considering the trajectory tracking formulation for underactuated systems. The goal is to regulate the controlled degrees of freedom (DOF), the translational position, x, y and z, and the yaw angle, ψ, and stabilize the...
Article
This paper describes the modeling and control of a birotor aircraft with tiltrotor configuration for the path tracking problem. The equations of motion of the tilrotor UAV is derived using Euler-Lagrange formulation, resulting in a nonlinear eight degrees-of-freedom dynamic model. To perform the control design, a linearized error model is obtained...
Conference Paper
The use of anytime algorithms (AAs) in real-time systems is not a novelty. Such approach is normally adopted in situations where the WCET of a given task is either unknown or highly pessimistic in comparison with the average execution time. Thereby, AAs provide certain flexibility for stringent real-time applications. In this paper we present the u...
Conference Paper
In this paper we present a project aimed for the designing of a small scale Unmanned Aerial Vehicle (UAV) with Tiltrotor configuration (that uses two rotating rotors). The proposed UAV is build from scratch, based on Commercial Off-The-Shelf (COTS) components. The related development ranges from designing the control algorithms to the wireless comm...