Planing force identification in high-speed underwater vehicles

2016 ◽  
Vol 22 (20) ◽  
pp. 4176-4191 ◽  
Author(s):  
Mojtaba Mirzaei ◽  
Mohammad Eghtesad ◽  
Mohammad Mahdi Alishahi
Keyword(s):  
High Speed ◽  
Hybrid Control ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Underwater Vehicles ◽  
The Body ◽  
Force Identification ◽  
Control Approach ◽  
Control Scheme ◽  
Highly Nonlinear

One of the most important issues, which high-speed underwater vehicles (HSUV) deal with, is the so-called planing force. The dynamic of HSUV includes two separate phases called planing phase and non-planing phase. Ideally, in perfect flight, the vehicle should fly within the cavity walls. However, in practice, the vehicle impacts on the cavity boundaries due to disturbances. The magnitude of the planing force is large and has a strong effect on dynamics of HSUV. However, planing force modeling is often too simple and therefore inaccurate, due to the nonlinear interaction among the solid, liquid, and gaseous phases, which is not well understood yet. Consequently, planing force identification is of great importance and should be studied in details. The present paper discusses the identification of the planing force in HSUV. For this purpose, the equations of motion are developed for the HSUV in the planing phase while the tail and the body end impact on the cavity wall. Then, a robust hybrid switching control approach is employed to deal with the highly nonlinear behavior of the underwater vehicle as it is influenced by the liquid-gas boundary interactions. An on-line planing force identification based on Lyapunov function is considered within designing controller procedure, thus the stability of the system is guaranteed. Lateral and longitudinal planing force identification are achieved and discussed. Compared to the proportional-integral-derivative control scheme, the hybrid control scheme seems to increase the stabilization of HSUV, which is useful in avoiding unsteady changes of cavity shape.

Tilt-Wing Rotorcraft Dynamic Analysis Using Multibody Formulation

1992 ◽  
Author(s):  
Patrick J. O’Heron ◽  
Parviz E. Nikravesh ◽  
Ara Arabyan ◽  
Donald L. Kunz
Keyword(s):  
Flight Control ◽  
High Speed ◽  
Equations Of Motion ◽  
Flight Path ◽  
Minimal Set ◽  
Near Wake ◽  
Highly Nonlinear ◽  
Nonlinear Transient ◽  
Nonlinear Transient Dynamics ◽  
Rotor Assembly

Abstract A model is presented that can be used to simulate the highly nonlinear transient dynamics associated with advanced rotorcraft conversion processes. Multibody equations of motion of the fuselage, the tilting wing, and the rotor assembly are derived using a minimal set of coordinates. An enhanced aerodynamics model is employed to account for unsteadiness and nonlinearity in the near-wake aerodynamics, with a dynamic uniform inflow to compute the far-wake aerodynamics, and a flight control system is employed to compute the blade pitch settings that are necessary to achieve a desired flight path. The model is subjected to a demanding flight path simulation to illustrate that it can perform vertical take-off, hover, tilt-wing conversion, and high-speed forward flight maneuvers effectively.

A New Cast Stone Roller Kiln and its Combustion Control Approach

2012 ◽  
Vol 605-607 ◽  
pp. 428-432 ◽  
Author(s):  
Jing Chen ◽  
Ai Jun Luo ◽  
You Xin Yuan ◽  
Chun Xiao ◽  
Wang Lin Wang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
High Speed ◽  
High Energy ◽  
Combustion Control ◽  
Cast Stone ◽  
Roller Kiln ◽  
Control Approach ◽  
Control Scheme ◽  
Dense Distribution ◽  
High Energy Consumption

The domestic cast stone industrial production is of high energy consumption and low productivity, so a new cast stone roller kiln is firstly developed. A combustion control approach is advanced to accommodate the new roller kiln architecture and meet the combustion control requirements. Continuous proportion and pulse control methods are adopted to the high-speed isothermal burners with internal dense distribution. Two controllers mutually collaborated in pairs to obtain the internal uniform temperature. The implementation of the combustion control scheme is put forward. The application results demonstrated that the new roller kiln and combustion controller could effectively decrease the furnace temperature difference, increase stability of the combustion atmosphere, improve product quality, reduce energy consumption and NOx emissions.

On The Steady State and Dynamic Performance Characteristics of Floating Ring Bearings

1981 ◽  
Vol 103 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Chin-Hsiu Li ◽  
S. M. Rohde
Keyword(s):  
Steady State ◽  
Linear Theory ◽  
High Speed ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Journal Bearings ◽  
Transient Problem ◽  
The Stability ◽  
Bearing System

An analysis of the steady state and dynamic characteristics of floating ring journal bearings has been performed. The stability characteristics of the bearing, based on linear theory, are given. The transient problem, in which the equations of motion for the bearing system are integrated in real time was studied. The effect of using finite bearing theory rather than the short bearing assumption was examined. Among the significant findings of this study is the existence of limit cycles in the regions of instability predicted by linear theory. Such results explain the superior stability characteristics of the floating ring bearing in high speed applications. An understanding of this nonlinear behavior, serves as the basis for new and rational criteria for the design of floating ring bearings.

A unified force control approach to autonomous underwater manipulation

Robotica ◽  
2001 ◽  
Vol 19 (3) ◽  
pp. 255-266 ◽  
Author(s):  
Yong Cui ◽  
Nilanjan Sarkar
Keyword(s):  
Force Control ◽  
Autonomous Underwater Vehicle ◽  
Hybrid Control ◽  
Impedance Control ◽  
Underwater Vehicle ◽  
Robotic System ◽  
Control Approach ◽  
Control Scheme ◽  
Underwater Manipulation ◽  
Six Degree Of Freedom

A unified force control scheme for an autonomous underwater robotic system is proposed in this paper. This robotic system is composed of a six degree-of-freedom autonomous underwater vehicle (AUV) and a robotic arm that is mounted on the AUV. A unified force control approach, which combines impedance control with hybrid position/force control by means of fuzzy switching to perform autonomous underwater manipulation, is presented in this paper. This controller requires a dynamic model of the underwater vehicle-manipulator system. However, it does not require any model of the environment and therefore will have the potential to be useful in underwater tasks where the environment is generally unknown. The proposed approach combines the advantages of impedance control with hybrid control so that both smooth contact transition and force trajectory tracking can be achieved. In the absence of any functional autonomous underwater vehicle-manipulator system that can be used to verify the proposed controller, extensive computer simulations are performed and the results are presented in the paper.

scholarly journals A Novel Control Approach to Hybrid Multilevel Inverter for High-Power Applications

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4563
Author(s):  
Muhammad Ali ◽  
Ghulam Hafeez ◽  
Ajmal Farooq ◽  
Zeeshan Shafiq ◽  
Faheem Ali ◽  
...  
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Multilevel Inverter ◽  
Computationally Efficient ◽  
Matlab Simulink ◽  
Control Approach ◽  
Control Scheme ◽  
Hybrid Control Scheme

This paper proposes a hybrid control scheme for a newly devised hybrid multilevel inverter (HMLI) topology. The circuit configuration of HMLI is comprised of a cascaded converter module (CCM), connected in series with an H-bridge converter. Initially, a finite set model predictive control (FS-MPC) is adopted as a control scheme, and theoretical analysis is carried out in MATLAB/Simulink. Later, in the real-time implementation of the HMLI topology, a hybrid control scheme which is a variant of the FS-MPC method has been proposed. The proposed control method is computationally efficient and therefore has been employed to the HMLI topology to mitigate the high-frequency switching limitation of the conventional MPC. Moreover, a comparative analysis is carried to illustrate the advantages of the proposed work that includes low switching losses, higher efficiency, and improved total harmonic distortion (THD) in output current. The inverter topology and stability of the proposed control method have been validated through simulation results in MATLAB/Simulink environment. Experimental results via low-voltage laboratory prototype have been added and compared to realize the study in practice.

scholarly journals Integral Backstepping Control of Induction Machine

2021 ◽  
Vol 23 (4) ◽  
pp. 345-351
Author(s):  
Abdelhak Benheniche ◽  
Farid Berrezzek
Keyword(s):  
High Speed ◽  
Induction Machine ◽  
Lyapunov Theory ◽  
System Stability ◽  
External Disturbances ◽  
Control Approach ◽  
Integral Action ◽  
Resistance Variation ◽  
Control Scheme ◽  
Rotor Flux

The goal of this work is to propose a latest design of a rotor speed and rotor flux modulus control approach for an induction machine using a Backstepping corrector with an integral action. The advantage of the Backstepping Strategy is the ability to manage a nonlinear system. The Lyapunov theory has been used to ensure the system stability. To improve the controller robustness proprieties the integral action is used, despite the system uncertainties and the existence of external disturbances. The unavailable rotor flux is recovered by estimation of the rotor flux of the machine based on the integration of the stator voltage expressions. The simulation results illustrate the effectiveness of the proposed control scheme under load disturbances, rotor resistance variation and low and high speed.

scholarly journals Damping Multimode Switching Control of Semiactive Suspension for Vibration Reduction in a Wheel Loader

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Tao Wei ◽  
Liu Zhiqiang
Keyword(s):  
High Speed ◽  
Hybrid Control ◽  
Vibration Reduction ◽  
Suspension System ◽  
Control Procedure ◽  
Discrete Events ◽  
Wheel Loader ◽  
Control Approach ◽  
Damping Control ◽  
Semiactive Suspension

The aim of this work is the control design and analysis of a semiactive axle suspension system for vibration reduction in a wheel loader. Unlike a traditional semiactive suspension system with continuously adjustable shock absorber, in this work, a novel axle suspension with multiple damping modes is proposed for the wheel loader. The multimode switching damping characteristics are achieved by just changing the discrete statuses of two high-speed switch electromagnetic valves, which makes the damping adjustment simpler and more reliable. However, because of the existence of discrete events, i.e., the on-off statuses of switch electromagnetic valves, the axle suspension proposed for the wheel loader poses a challenging hybrid control problem. To solve this problem, the mixed logical dynamical (MLD) modeling approach for hybrid systems is applied to model the dynamic characteristics of the system damping control procedure. Using this model, a hybrid model predictive control (HMPC) strategy is further designed, which can determine the optimal switching sequences of the discrete damping modes according to the axle suspension performance indices. Finally, to verify the effectiveness of the proposed semiactive axle suspension with multiple damping modes and its control approach, simulation analyses are conducted.

Pulse Width Modulation of Water Jet Propulsion Systems Using High-Speed Coanda-Effect Valves

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Anirban Mazumdar ◽  
H. Harry Asada
Keyword(s):  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Pulse Height ◽  
Underwater Vehicles ◽  
Water Jet ◽  
Control Algorithms ◽  
Control Scheme ◽  
Pump Output ◽  
Valve Switching

An integrated high-speed valve switching and pump output control scheme are developed for precision maneuvering of underwater vehicles. High-speed Coanda-effect valves combined with a centrifugal pump allow for precise control of thrust force using a unique pulse width modulation (PWM) control scheme, where both pulse width and pulse height are controlled in a coordinated manner. Dead zones and other complex nonlinear dynamics of traditional propeller thrusters and water jet pumps are avoided with use of the integrated pump-valve control. Three control algorithms for coordinating valve switching and pump output are presented. A simplified nonlinear hydrodynamic model of underwater vehicles is constructed, and design trade-offs between PWM frequency and pulse height, with regard to steady state oscillations, are addressed. The control algorithms are implemented on a prototype underwater vehicle and the theoretical results are verified through experiments.

Sensitivity of Final Field Position to the Punt Initial Conditions in American Football

2016 ◽  
Author(s):  
James D. Turner ◽  
Brian P. Mann
Keyword(s):  
Initial Conditions ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Basins Of Attraction ◽  
Three Dimensions ◽  
American Football ◽  
Impact Forces ◽  
Highly Nonlinear ◽  
Angular Velocities ◽  
Field Position

The starting field position is often a deciding factor in an American football game. In the case of a defensive stop, a kick, known as a punt, is used to give the receiving team a field position that is more advantageous to the kicking team when possession changes. The goal of the punter is to kick the ball along a desired flight path, where a delicate balance between the distance traveled before impact, hang time in the air, and the distance traveled after bouncing is favorable for the kicking team. However, the punter has only imprecise control over the initial conditions, such as the angular velocity, linear velocity, and orientation of the football. Due to the highly nonlinear behavior of the football, from aerodynamic and impact forces, even small changes in initial conditions can produce large changes in the final position of the football, but there may be regions of initial conditions with relatively consistent results. If punters could target such large contiguous regions of initial conditions with desirable football paths, they could improve their chances of successful kicks. For nonlinear systems, basins of attraction diagrams are often used to graphically display the initial conditions that lead to different final attractors. In this case, the regions of initial conditions that lead to a desirable final field position can be grouped and shown graphically. A numerical simulation program was developed including models for aerodynamic flight and bouncing of the irregularly shaped football. The flight model used fourth order Runge-Kutta integration of the equations of motion of the football, including gravitational and aerodynamic forces and moments with empirical lift, drag, and yaw coefficients in three dimensions. The bounce model was based on an empirical two-dimensional coefficient of restitution model that was published in the literature. The behavior of a football in flight and during bouncing was simulated for a range of initial angular velocities and launch angles, and the characteristics of the flight paths were analyzed. The characteristics of some regions of initial conditions were relatively sensitive to small changes, while other regions were relatively uniform. This shows that this approach, with a quantitatively accurate bounce model, could be practically applied to develop a guide for punters to optimize their kicks. With such a guide and sufficient practice, punters could select and target the larger regions of initial conditions that produced desirable behavior, which would improve their chances of successful punts.

Dynamic Model of a Vertical Piano Action Mechanism

2009 ◽  
Author(s):  
Ramin Masoudi ◽  
Stephen Birkett ◽  
John McPhee
Keyword(s):  
High Speed ◽  
Equations Of Motion ◽  
Geometrical Parameters ◽  
Action Mechanism ◽  
High Speed Imaging ◽  
Multibody Model ◽  
Highly Nonlinear ◽  
Scanned Images ◽  
Grand Piano ◽  
Real Action

The dynamic behavior of a vertical piano action mechanism is studied using a simulation model and compared qualitatively to observations obtained by high-speed imaging of a real action. The simulated response of all components is obtained for two different prescribed input force profiles applied at the key front. These inputs represent in simplified form the general shape of a typical force input by a pianist measured at the key surface for a strong (forte) strike, or two key strikes in rapid succession. The graph-theoretic multibody model constructed represents the components and their interactions. Explicit contact edges provide forces generated between two bodies as a function of their kinematic states, using a special contact model to represent the compression of felt lined interfaces that can separate during the key stroke. Masses and geometrical parameters of the action were measured by importing scanned images from a real action into CAD software. The highly nonlinear system of five ordinary differential equations of motion was derived symbolically and solved by a numerical stiff solver in Maple. The effects of two components not present in the horizontal grand piano action, the bridle strap and hammer butt spring, were examined using simulations. The butt spring is seen to serve an important function in assisting the return of the hammer to its rest position on key release. The model will be useful in future studies to compare vertical actions to horizontal grand piano actions, as these are known to exhibit quite different playing characteristics.

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