Modeling and Predictive Control of an Unmanned Underwater Vehicle

2019 ◽  
Author(s):  
Renato Rodriguez Nunez ◽  
Damoon Soudbakhsh
Keyword(s):  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Travel Speed ◽  
The State ◽  
Operating Conditions ◽  
State Variables ◽  
Unmanned Underwater Vehicles ◽  
Six Degrees Of Freedom ◽  
State Space System ◽  
Predictive Controller

Abstract This paper presents a model and optimal controller for Unmanned Underwater Vehicles (UUVs). We present a nonlinear six degrees of freedom model of the UUV that includes hydrodynamic and hydrostatic terms. To design the controller, we simplify the model using the geometry of the UUV as well as its operating conditions such as the depth and expected travel speed. Instead of designing a controller for the state space system, we used feedback linearization technique to decouple the motions. Then, a set of controllers were designed for each motion. To incorporate the constraints on the input and the state variables, we designed a fast Model Predictive Controller (MPC) for the UUV and compared its performance with a conventional controller.

Nonlinear system controllability analysis and autopilot design for bank-to-turn aircraft with two flaps

2018 ◽  
Vol 233 (5) ◽  
pp. 1772-1783 ◽  
Author(s):  
Jinlu Dong ◽  
Di Zhou ◽  
Chuntao Shao ◽  
Shikai Wu
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Nonlinear System ◽  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Lyapunov Stability Theory ◽  
Zero Dynamics ◽  
Controlled System ◽  
Linearization Technique ◽  
Six Degrees Of Freedom

In this study, the six-degrees-of-freedom flight motion of a tail-controlled bank-to-turn aircraft with two flaps is described as a nonlinear control system. The controllability of this flap-controlled system is analyzed based on nonlinear controllability theory and the system is proved to be weakly controllable. By choosing the angle-of-attack and roll angle as the outputs of this control system, the zero dynamics of the system are analyzed using Lyapunov stability theory, and are proved to be stable under some conditions given by an inequality. Then an autopilot is designed for this system using the feedback linearization technique. Results of the numerical simulation for this control system show the effectiveness of the controllability analysis and autopilot design.

A Method for Solving Large-Scale Multiloop Constrained Dynamical Systems Using Structural Decomposition

2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Tao Xiong ◽  
Jianwan Ding ◽  
Yizhong Wu ◽  
Liping Chen ◽  
Wenjie Hou
Keyword(s):  
Dynamical Systems ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
The State ◽  
State Variables ◽  
Structural Decomposition ◽  
Multiple Degrees Of Freedom ◽  
Constraint Equations ◽  
Constrained Dynamical Systems ◽  
Algebraic Constraint

A structural decomposition method based on symbol operation for solving differential algebraic equations (DAEs) is developed. Constrained dynamical systems are represented in terms of DAEs. State-space methods are universal for solving DAEs in general forms, but for complex systems with multiple degrees-of-freedom, these methods will become difficult and time consuming because they involve detecting Jacobian singularities and reselecting the state variables. Therefore, we adopted a strategy of dividing and conquering. A large-scale system with multiple degrees-of-freedom can be divided into several subsystems based on the topology. Next, the problem of selecting all of the state variables from the whole system can be transformed into selecting one or several from each subsystem successively. At the same time, Jacobian singularities can also be easily detected in each subsystem. To decompose the original dynamical system completely, as the algebraic constraint equations are underdetermined, we proposed a principle of minimum variable reference degree to achieve the bipartite matching. Subsequently, the subsystems are determined by aggregating the strongly connected components in the algebraic constraint equations. After that determination, the free variables remain; therefore, a merging algorithm is proposed to allocate these variables into each subsystem optimally. Several examples are given to show that the proposed method is not only easy to implement but also efficient.

scholarly journals A flatness-based predictive controller for six-degrees of freedom spacecraft rendezvous

2020 ◽  
Vol 167 ◽  
pp. 391-403 ◽  
Author(s):  
Julio C. Sanchez ◽  
Francisco Gavilan ◽  
Rafael Vazquez ◽  
Christophe Louembet
Keyword(s):  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Predictive Controller

Trajectory Control of an Automated Guided Vehicle Using Feedback Linearization

2006 ◽  
Author(s):  
S. M. Mehdi Ansarey M. ◽  
M. J. Mahjoob
Keyword(s):  
Control System ◽  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Automated Guided Vehicle ◽  
State Variables ◽  
Discrete Curvatures ◽  
Steering Mechanism ◽  
Dynamics And Control ◽  
And Control ◽  
Three Degrees Of Freedom

In this paper, the dynamics and control of an automated guided vehicle (AGV) is described. The objective is to control the vehicle direction and location with respect to a prescribed trajectory. This is accomplished based on an optimum control strategy using vehicle state variables. A four-wheel vehicle with three degrees of freedom including longitudinal, lateral and yaw motion is considered. The nonlinearity of the tire and steering mechanism is also included. The control system design for circular, straight forward and composite path is presented based on feedback linearization. Some trajectory simulation for discrete curvatures is carried out. The controller was implemented within MATLAB environment. The design was also evaluated using ADAMS full vehicle assembly. The results demonstrated the accuracy of the model and the effectiveness of the developed control system.

Nonlinear Observers for Constrained Systems

2009 ◽  
Author(s):  
Giscard A. Kfoury ◽  
Nabil G. Chalhoub
Keyword(s):  
Degrees Of Freedom ◽  
Sliding Mode ◽  
The State ◽  
Constrained Systems ◽  
State Variables ◽  
Nonlinear Observers ◽  
Constraint Equations ◽  
Single Cylinder Engine ◽  
Robust Observers ◽  
Selection Of

Three procedures for designing robust observers to estimate the state variables of nonlinear constrained systems have been developed in this work. All observers are based on the sliding mode methodology and assume that the number of transducers matches that of the degrees of freedom of the system. The conceptual differences between the proposed observer designs are in the number and selection of the sliding surfaces along with the formulations pertaining to their nominal models. The observers have been applied to estimate the state variables of a crank-slider mechanism of a single cylinder engine. The simulation results demonstrate the capabilities of the observers in accurately estimating the state variables of the system, including the superfluous ones, in the presence of significant structured and unstructured uncertainties. In addition, the results show that the nominal constraint equations are satisfied by the estimated state variables.

Hardware Design for State Vector Identification of a Small Helicopter Model

2013 ◽  
Vol 282 ◽  
pp. 107-115 ◽  
Author(s):  
Viliam Fedák ◽  
Ján Bačík
Keyword(s):  
Degrees Of Freedom ◽  
Sensory System ◽  
Hardware Design ◽  
Sensor Data ◽  
State Variables ◽  
Six Degrees Of Freedom ◽  
Long Term Stability ◽  
Helicopter Flight ◽  
Embedded Computer

The paper deals with hardware design for sensory system of a small helicopter model that is characterized by a long-term stability and in real time generates data about helicopter state variables during helicopter flight. The sensor system is based on powerful 32-bit processors with the cores ARM7 and Cortex-M3. The main unit for data processing presents an embedded computer built on a mini-ITX motherboard with processor Intel i3. As the helicopter presents a system with six degrees of freedom and in the fact, during the flight, there is not any fixed point that would enable to caliber the sensors placed on the helicopter board, for processing of sensor data complex stochastic calculations are necessary. They are based on the discrete Kalman filter that present a main computing tool of the control system.

scholarly journals Analysis of thermal states of a flat-solar collector using state variables

2020 ◽  
Vol 154 ◽  
pp. 05009
Author(s):  
Paweł Obstawski ◽  
Tomasz Bakoń ◽  
Anna Kozikowska
Keyword(s):  
Solar Collector ◽  
Dynamic Properties ◽  
Exchange Process ◽  
The State ◽  
Operating Conditions ◽  
Solar Heating ◽  
State Variables ◽  
Analogue Model ◽  
Heating Installation ◽  
Thermal States

This paper analyses the thermal states of the flat solar collector using the state variable method. The knowledge of the transient states describing the state of the solar heating installation under operating conditions enables the analysis of the heat exchange process and the development of control strategies. The analysis of variable states under operating conditions requires the development of a mathematical model describing the dynamic properties of the whole solar heating installation and the definition of the variables describing the state of the system from the energy balance perspective. The paper presents a method enabling the analysis of variables in the condition of a solar heating installation and a single solar collector based on the comparison of two models: an analogue model developed by the Equivalent Thermal Network method and a digital model, developed on the basis of performance data by the Parametric Identification method.

Observability, Reconstructibility and Observer Design for Linear Mechanical Systems Unobservable in Absence of Impacts†

2003 ◽  
Vol 125 (4) ◽  
pp. 549-562 ◽  
Author(s):  
Francesco Martinelli ◽  
Laura Menini ◽  
Antonio Tornambe`
Keyword(s):  
Structural Properties ◽  
Degrees Of Freedom ◽  
Mechanical Systems ◽  
The State ◽  
Observer Design ◽  
State Variables ◽  
Multiple Degrees Of Freedom ◽  
Position Variable

This paper deals with a class of mechanical systems, constituted by two composite bodies which interact with each other only during collisions: since only one position variable of only one body is measured, the whole system would not be observable without impacts. Each body is possibly constituted by several masses connected by linear springs, so that the internal deformations can be taken into account (the so-called multiple-degrees-of-freedom impacts). For two relevant and different cases, the structural properties of observability and reconstructibility are studied, and observers are proposed in order to estimate all the state variables, including those that would be unobservable in absence of impacts.

scholarly journals Complex interplay between stress perturbations and viscoelastic relaxation in a two-asperity fault model

2017 ◽  
Author(s):  
Emanuele Lorenzano ◽  
Michele Dragoni
Keyword(s):  
Degrees Of Freedom ◽  
Discrete Dynamical System ◽  
The State ◽  
Viscoelastic Relaxation ◽  
State Variables ◽  
Simple Correlation ◽  
Complex Interplay ◽  
Viscoelastic Deformation ◽  
Tectonic Loading ◽  
Three Degrees Of Freedom

Abstract. We consider a plane fault with two asperities embedded in a shear zone, subject to a uniform strain rate owing to tectonic loading. After an earthquake, the static stress field is relaxed by viscoelastic deformation. We treat the fault as a discrete dynamical system with three degrees of freedom: the slip deficits of the asperities and the variation of their difference due to viscoelastic deformation. The dynamics of the system is described in terms of one sticking mode and three slipping modes. We consider the effect of stress transfers connected to earthquakes produced by neighbouring faults. The perturbation is studied in terms of a vector in the state space, whose components are the changes in the state variables of the system. The interplay between the stress perturbation and the viscoelastic relaxation significantly complicates the evolution of the fault and its seismic activity. We show that the presence of viscoelastic relaxation prevents any simple correlation between the change of Coulomb stresses on the asperities and the anticipation or delay of their failures. As an application, we study the effects of the 1999 Hector Mine, California, earthquake on the post-seismic evolution of the fault that generated the 1992 Landers, California, earthquake, which we model as a two-mode event associated with the consecutive failure of two asperities.

WITT: Harvesting Energy From Subsea, Vortex-Induced Vibration

2019 ◽  
Vol 53 (4) ◽  
pp. 17-25
Author(s):  
Martin John Wickett ◽  
Simon Hindley ◽  
Mairi B. Wickett
Keyword(s):  
Degrees Of Freedom ◽  
Electrical Power ◽  
Operating Conditions ◽  
Modular System ◽  
Transfer Energy ◽  
Energy Device ◽  
Vortex Induced Vibration ◽  
Six Degrees Of Freedom ◽  
Numerical Predictions ◽  
Wide Range

AbstractThe WITT (Whatever Input to Torsion Transfer) energy harvesting device converts chaotic motion in six degrees of freedom to a single unidirectional output, which can be coupled to a generator to provide electrical power. The WITT energy device of this size order has an operational sweet spot of approximately 2 Hz, with up to 100 mm amplitude displacements, although it is tunable within the WITT device by varying the pendulum length and mass. To operate in this nature, subsea vortex-induced vibration (VIV) was chosen to drive the system. This is achieved by connecting the WITT energy transmission to cylindrical cross-section pipe sections, creating a modular system that can be varied for sites with different conditions or power requirements. Numerical predictions were performed for a wide range of design variations over a broad range of operating conditions using different VIV calculation techniques. This informed the likely dimensions for different sites and power requirements, so that an off-the-shelf solution could be quickly provided to a client, providing a sealed modular subsea energy solution. Tank testing was performed to compare to the numerical predictions and determine the effect of the WITT energy device on the system dynamics, demonstrating the concept is feasible. A range of possible applications are provided, from powering subsea monitoring equipment through to reduction of riser fatigue by reducing VIV.

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