Compound sliding-mode predictive control for a temperature system of high-speed heat-airflow wind tunnel

2013 ◽  
Vol 228 (11) ◽  
pp. 1869-1879 ◽  
Author(s):  
Chaozhi Cai ◽  
Yunhua Li ◽  
Sujun Dong
Keyword(s):  
Wind Speed ◽  
High Speed ◽  
Sliding Mode ◽  
Fast Response ◽  
Feedback Controller ◽  
Compound Control ◽  
The Impact ◽  
The Mathematical Model ◽  
Valve Control ◽  
Ramp Signal

The mathematical model of the temperature system under the mode of the proportional throttle valve control and the variable frequency pump control is established, respectively. A compound control strategy that consists of a compensation controller and a sliding-mode predictive feedback controller is designed. The compensation controller, which takes the change of the wind speed as parameter, is used to eliminate the impact on the system caused by the change of the working conditions (wind speed); the sliding-mode predictive feedback controller is used to solve the problems in the system such as time delay, time-varying parameters and disturbance. In order to solve the problem of temperature disturbance caused by the mode switch between pump control and valve control and the oil-rich combustion phenomenon in the high-temperature case, a method takes the ramp signal in which the slope is adjustable as a temperature setting signal is proposed. The experimental results show that the designed strategy obtains a satisfactory control performance and can achieve the temperature control with fast response time and no overshoot. In addition, it takes the ramp signal in which the slope is adjustable as the temperature setting signal can achieve the undisturbed switching control of the temperature and prevent the oil-rich combustion effectively.

The Simulation Analysis of the High Speed Switch Valve Control the Cartridge Valve Based on AMEsim

2014 ◽  
Vol 971-973 ◽  
pp. 827-832
Author(s):  
Yan Jin Qin ◽  
Zhang Yong Wu ◽  
Zi Yong Mo ◽  
Xian Wang ◽  
Juan Wang
Keyword(s):  
Duty Cycle ◽  
High Frequency ◽  
High Speed ◽  
Simulation Analysis ◽  
Simulation Software ◽  
Pulse Width Modulated ◽  
Working Principle ◽  
The Impact ◽  
The Mathematical Model ◽  
Valve Control

To establish the mathematical model of the system of high speed switch valve control the cartridge valve based on analyzing the working principle of the system,and then to analyze the impact of selecting different input signal of high speed solenoid valve and different duty cycle of PWM pulse width modulated signal through simulation software AMSEsim. The results obtained in the high-frequency performance is not very satisfactory, but in the low signal and moderate duty cycle, high-speed switch valve can be good linear control of the cartridge valve.

Dynamic vacuum pressure tracking control with high-speed on-off valves

2018 ◽  
Vol 232 (10) ◽  
pp. 1325-1336 ◽  
Author(s):  
Gang Yang ◽  
Kai Chen ◽  
Linglong Du ◽  
Jingmin Du ◽  
Baoren Li
Keyword(s):  
Mass Flow ◽  
Pulse Width ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Sliding Mode ◽  
Tracking System ◽  
Vacuum Pressure ◽  
Chamber Pressure ◽  
Asymmetric Structure ◽  
The Impact

A vacuum pressure tracking system with high-speed on-off valves is a discontinuous system due to the discrete nature of high-speed on-off valves. Chamber pressure changes in the system are determined by the mass flow rates during the processes of charging and discharging. Here, a sliding mode controller with an asymmetric compensator based on average mass flow rate is designed for accurate vacuum pressure tracking. The controller output signal is converted into the duty cycles of the high-speed on-off valves via a pulse width modulation pulsing scheme. Owing to the extreme asymmetry of the processes, an asymmetric structure comprising one high-speed on-off valve in the charging unit and three high-speed on-off valves in the discharging unit is applied to weaken the impact of asymmetry. In addition, an asymmetric compensator is also designed to modify the pulse width modulation pulsing scheme to further eliminate the asymmetry. Experimental results indicate that the proposed controller achieves better performance in pressure tracking with the asymmetric compensator overcoming process asymmetry and enhancing system robustness.

scholarly journals Numerical Modeling and Experimental Verification for High-Speed and Heavy-Load Planar Mechanism with Multiple Clearances

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Fangang Meng ◽  
Shijing Wu ◽  
Fan Zhang ◽  
Liang Liang
Keyword(s):  
High Speed ◽  
Circuit Breaker ◽  
Fast Response ◽  
Transmission Mechanism ◽  
Heavy Load ◽  
Clearance Joints ◽  
Moving Contact ◽  
Center Path ◽  
The Impact ◽  
Impact Motion

Transmission mechanism is one of the most important parts of the Ultra-High Voltage (UHV) circuit breaker. It has specific characteristics such as fast response, high speed, and heavy load in the processes of open and close actions. This paper studies the effects of multiple clearances on the working characteristics of transmission mechanism system, especially the motion of its journal center path during operation. It builds a nonlinear kinetic model of transmission mechanism considering the system energy losses due to the impact and friction between the journal and bearing inside clearance joints. Also, an experimental platform is built to measure the displacement and velocity of the moving contact. The results show that the existence of 15 clearance joints in our mechanism system can cause hysteresis effects on the velocity and acceleration of the moving contact, as well as its acceleration fluctuation. Meanwhile, the increase of friction coefficient will stabilize the dynamic characteristic. In addition, both the experimental and simulation results indicate that the motion of the journal center, which is unevenly distributed along the circle, is characterized by three phases: free flight motion, contact motion, and impact motion.

scholarly journals Моделирование механических свойств сильно неоднородных систем под внешним воздействием

2019 ◽  
Vol 89 (7) ◽  
pp. 1059
Author(s):  
П.А. Александров ◽  
А.Б. Свечников ◽  
В.В. Горев ◽  
E.V. Ryan ◽  
W.H. Ryan ◽  
...  
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Functional Form ◽  
Spatial Scales ◽  
Calculated Data ◽  
Heterogeneous Structure ◽  
Destruction Process ◽  
Method Of Molecular Dynamics ◽  
The Impact ◽  
The Mathematical Model

AbstractLaboratory tests that were supplemented by a new numerical model have been conducted to study mechanical properties of asteroids with a highly heterogeneous structure. The functional form of the method of molecular dynamics, which was extended to macroscopic spatial scales, has been used in the numerical model. In the experiment, targets that were composed of glass balls, which were bonded by conventional ice, interacted with fast impactors. High-speed cameras recorded the destruction process of the ice matrix and preservation of glass balls without damage. In parallel, parameterization of the mathematical model was performed and calculated data have been compared with the experiment. The energy range of impactors when the impact causes deflection of the target with minimal destruction was able to be determined.

Experimental and Numerical Investigation of the Unsteady Flow Field in a Vaned Diffuser of a High-Speed Centrifugal Compressor

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Klemens Vogel ◽  
Reza S. Abhari ◽  
Armin Zemp
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Fast Response ◽  
Operating Conditions ◽  
Wake Flow ◽  
Vaned Diffuser ◽  
Wide Range ◽  
The Impact

Vaned diffusers in centrifugal compressor stages are used to achieve higher stage pressure ratios, higher stage efficiencies, and more compact designs. The interaction of the stationary diffuser with the impeller can lead to resonant vibration with potentially devastating effects. This paper presents unsteady diffuser vane surface pressure measurements using in-house developed, flush mounted, fast response piezoresistive pressure transducers. The unsteady pressures were recorded for nine operating conditions, covering a wide range of the compressor map. Experimental work was complemented by 3D unsteady computational fluid dynamics (CFD) simulations using ansys cfx V12.1 to detail the unsteady diffuser aerodynamics. Pressure fluctuations of up to 34.4% of the inlet pressure were found. High pressure variations are present all along the vane and are not restricted to the leading edge region. Frequency analysis of the measured vane surface pressures show that reduced impeller loading, and the corresponding reduction of tip leakage fluid changes the characteristics of the fluctuations from a main blade count to a total blade count. The unsteady pressure fluctuations in the diffuser originate from three distinct locations. The impact of the jet-wake flow leaving the impeller results in high variation close to the leading edge. It was observed that CFD results overpredicted the amplitude of the pressure fluctuation on average by 62%.

Rotor-current-based fault detection for doubly-fed induction generator using new sliding mode observer

2020 ◽  
Vol 42 (16) ◽  
pp. 3110-3122
Author(s):  
Wenxin Yu ◽  
Dan Jiang ◽  
Junnian Wang ◽  
Ruiqi Li ◽  
Lu Yang
Keyword(s):  
Fault Detection ◽  
Sliding Mode ◽  
Fast Response ◽  
Sliding Mode Observer ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Simulink Simulation ◽  
Doubly Fed ◽  
Stator Fault ◽  
The Mathematical Model

To detect the fault of the doubly-fed induction generator (DFIG), in this paper, a fault detection method of novel sliding mode observer is proposed, without a velocity sensor. In addition to better elimination of chattering for the new sliding mode observer, at the same time, it has better stability and faster convergence speed than the traditional sliding mode observer. Firstly, the sliding mode observer is built according to the mathematical model of the DFIG. Then, the rotor current and the rotational speed are estimated. After comparing the actual rotor current value with the observed value, the self-detection of the fault for the DFIG is realized. Secondly, three faults of grid voltage sags failure, DFIG inter-turn stator fault and rotor current sensor fault are given respectively. After that the Simulink simulation model is built under different fault conditions. It is proved by simulation that this sliding mode observer can well detect faults occurring at different positions. Additionally, it can also be proved that the sliding mode observer has the characteristics of fast response and good stability.

Experimental and Numerical Investigation of the Unsteady Flow Field in a Vaned Diffuser of a High-Speed Centrifugal Compressor

2014 ◽  
Author(s):  
Klemens Vogel ◽  
Reza S. Abhari ◽  
Armin Zemp
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Fast Response ◽  
Operating Conditions ◽  
Wake Flow ◽  
Vaned Diffuser ◽  
Wide Range ◽  
The Impact

Vaned diffusers in centrifugal compressor stages are used to achieve higher stage pressure ratios, higher stage efficiencies and more compact designs. The interaction of the stationary diffuser with the impeller can lead to resonant vibration with potentially devastating effects. This paper presents unsteady diffuser vane surface pressure measurements using in-house developed, flush mounted, fast response piezo-resistive pressure transducers. The unsteady pressures were recorded for 9 operating conditions, covering a wide range of the compressor map. Experimental work was complemented by 3D unsteady CFD simulations using ANSYS CFX V12.1 to detail the unsteady diffuser aerodynamics. Pressure fluctuations of up to 34.4% of the inlet pressure were found. High pressure variations are present all along the vane and are not restricted to the leading edge region. Frequency analysis of the measured vane surface pressures show that reduced impeller loading and the corresponding reduction of tip leakage fluid changes the characteristics of the fluctuations from a main blade count to a total blade count. The unsteady pressure fluctuations in the diffuser originate from three distinct locations. The impact of the jet wake flow leaving the impeller results in high variation close to the leading edge. It was observed that CFD results overpredicted the amplitude of the pressure fluctuation on average by 62%.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

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