scholarly journals Control-Oriented Modeling of Transcritical Vapor Compression Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Bryan P. Rasmussen ◽  
Andrew G. Alleyne
Keyword(s):  
Model Reduction ◽  
Dynamic Model ◽  
Controller Design ◽  
Multiple Time ◽  
Vapor Compression ◽  
Nonlinear Dynamic Model ◽  
Air Conditioning System ◽  
Physical Insight ◽  
Multivariable Controller ◽  
Physical Phenomena

This paper presents a methodology for developing a low order dynamic model of a transcritical air-conditioning system, specifically suited for multivariable controller design. An 11th-order nonlinear dynamic model of the system is derived using first principles. Analysis indicates that the system exhibits multiple time scale behavior, and that model reduction is appropriate. Model reduction using singular perturbation techniques yields physical insight as to which physical phenomena are relatively fast/slow, and a 5th-order dynamic model appropriate for multivariable controller design. Although all results shown are for a transcritical cycle, the methodology presented can easily be extended to subcritical cycles.

Nonlinear Dynamic Model of a Fluidized-Bed Steam Generation System

1980 ◽  
Vol 102 (1) ◽  
pp. 202-208 ◽  
Author(s):  
A. Ray ◽  
D. A. Berkowitz ◽  
V. H. Sumaria
Keyword(s):  
Fluidized Bed ◽  
Dynamic Model ◽  
Controller Design ◽  
Digital Simulation ◽  
Steam Generation ◽  
Generation System ◽  
Nonlinear Dynamic Model ◽  
Continuous Time Model ◽  
Design Data ◽  
Time Model

A dynamic model of an atmospheric pressure fluidized-bed steam generation system is presented which allows digital simulation and analytical controller design. The nonlinear, time-invariant, deterministic, continuous-time model is derived in state-space form from conservation relations, empirical correlations and system design data. The model has been verified for steady-state and transient performance with measured data from experimental test runs. Transient responses of several process variables, following independent step disturbances in coal feed rate and air flow, are illustrated.

A simplified dynamic model and control for a multiple launch rocket system

2021 ◽  
pp. 107754632110093
Author(s):  
Bo Li ◽  
Xiaoting Rui ◽  
Guoping Wang
Keyword(s):  
Dynamic Model ◽  
Feedback Linearization ◽  
Controller Design ◽  
Euler Method ◽  
Nonlinear Controller ◽  
Nonlinear Dynamic Model ◽  
Position Accuracy ◽  
System A ◽  
And Control ◽  
Rocket System

Multiple launch rocket system, a type of launching platform used to launch kinetic load to hit the target, is an extremely complicated mechanical system with strong vibration because of the jet force. In this study, a nonlinear dynamic model and vibration control of a multiple launch rocket system are presented to reduce vibration and improve position accuracy. A simplified dynamic model of the multiple launch rocket system is derived using the Newton–Euler method, which facilitates the controller design considering the strong complexity of the multiple launch rocket system. On this basis, the feedback linearization technique is introduced to design a nonlinear controller based on the deduced dynamic model. The simulated and experimental results show that the simplified dynamic model–based control effectively can reduce vibration level of the launching system and make the azimuth and elevation angles reach the desired values with smaller error despite of each rocket’s jet force.

scholarly journals Nonlinear Dynamic Modeling and Model Reduction Strategy for Rotating Thin Cylindrical Shells

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Shupeng Sun ◽  
Lun Liu
Keyword(s):  
Model Reduction ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Nonlinear Dynamic ◽  
Degrees Of Freedom ◽  
Flexural Vibration ◽  
Nonlinear Dynamic Model ◽  
Thin Cylindrical Shell ◽  
Reduction Strategy ◽  
Nonlinear Dynamic Modeling

Nonlinear dynamic modeling and model reduction strategy are studied in this paper for a rotating thin cylindrical shell. The nonlinear dynamic model is first established in terms of ordinary differential equations, in which the effects of Coriolis and centrifugal forces are considered, as well as the initial hoop tension due to rotation. This model describes both the in-plane vibrations and the flexural vibration and reflects the coupling effects of those deformations. Based on this original model, a novel model reduction strategy is proposed to reduce the degrees of freedom by neglecting vibration modes predominated by in-plane vibrations. Meanwhile, for the reduced-order model, the in-plane vibrations’ contributions to the rotating shell’s response are still preserved. To validate the dynamic model and the model reduction strategy, comparisons and simulations are carried out. Subsequently, nonlinear dynamic behaviors are investigated preliminarily by analyzing the rotating cylindrical shell’s amplitude-frequency responses under different excitation levels.

Analysis of Tourism Ecology Capacity Based on the Nonlinear Dynamic Model

2009 ◽  
Vol 11 (2) ◽  
pp. 163-168
Author(s):  
Long LV ◽  
Zhenfang HUANG ◽  
Jiang WU
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Model

scholarly journals Development, Modeling and Control of a Dual Tilt-Wing UAV in Vertical Flight

Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 71
Author(s):  
Luz M. Sanchez-Rivera ◽  
Rogelio Lozano ◽  
Alfredo Arias-Montano
Keyword(s):  
Dynamic Model ◽  
Attitude Control ◽  
Test Bench ◽  
Aerodynamic Coefficients ◽  
Nonlinear Dynamic Model ◽  
Modeling And Control ◽  
Drag And Lift ◽  
And Control ◽  
Dynamics Method ◽  
Indoor And Outdoor

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.

Geometry optimization of a planar double wishbone suspension based on whole-range nonlinear dynamic model

2021 ◽  
pp. 095440702110262
Author(s):  
Zhihua Niu ◽  
Sun Jin ◽  
Rongrong Wang ◽  
Yansong Zhang
Keyword(s):  
Dynamic Model ◽  
Geometry Optimization ◽  
Analytical Models ◽  
Small Displacement ◽  
Nonlinear Dynamic Model ◽  
Computational Accuracy ◽  
Suspension Systems ◽  
Geometry Design ◽  
Dynamic Performances ◽  
Suspension Geometry

Dynamic analysis is an essential task in the geometry design of suspension systems. Whereas the dynamic simulation based on numerical software like Adams is quite slowly and the existing analytical models of the nonlinear suspension geometry are mostly based on small displacement hypothesis, this paper aims to propose a whole-range dynamic model with high computational efficiency for planar double wishbone suspensions and further achieve the fast optimal design of suspension geometry. Selection of the new generalized coordinate and explicit solutions of the basic four-bar mechanism dramatically reduce the complexity of suspension geometry representation and provide analytical solutions for all of the time varying dimensions. By this means, the running speed and computational accuracy of the new model are guaranteed simultaneously. Furthermore, an original Matlab/Simulink implementation is given to maintain the geometric nonlinearity in the solving process of dynamic differential equations. After verifying its accuracy with an ADAMS prototype, the presented whole-range model is used in the vast-parameter optimization of suspension geometry. Since both kinematic and dynamic performances are evaluated in the objective function, the optimization is qualified to give a comprehensive suggestion to the design of suspension geometry.

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