L1 Adaptive Control for Aircraft Air Management System Pressure-Regulating Bleed Valve

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
John Cooper ◽  
Chengyu Cao ◽  
Jiong Tang
Keyword(s):  
Management System ◽  
Control Valve ◽  
Pressure Control ◽  
Adaptive Controller ◽  
System Model ◽  
Flow Control Valve ◽  
L1 Adaptive Control ◽  
System Pressure ◽  
L1 Adaptive Controller ◽  
Linear Controllers

This paper presents an L1 adaptive controller for pressure control using an engine bleed valve in an aircraft air management system (AMS). The air management system is composed of two pressure-regulating bleed valves, a temperature control valve, a flow control valve, and a heat exchanger/precooler. Valve hysteresis due to backlash and dry friction is included in the system model. The nonlinearities involved in the system cause oscillations under linear controllers, which decrease component life. This paper is the unique in the consideration of these uncertainties for control design. This paper presents simulation results using the adaptive controller and compares them to those using a proportional–integral (PI) controller.

Automatic Aircraft Cabin Pressurization Systems

2019 ◽  
pp. 20-25
Author(s):  
Z.S. Sukhov ◽  
G.A. Timofeev
Keyword(s):  
Control Systems ◽  
Pid Controller ◽  
Pressure Control ◽  
Adaptive Controller ◽  
Testing Environment ◽  
Fuzzy Pid Controller ◽  
New Methods ◽  
Automatic Pressure ◽  
L1 Adaptive Controller ◽  
The Cost

This article presents a review of pneumatic, electro-pneumatic and digital systems for automatic pressure control in an airtight cabin and lists the types of aircraft where such systems are installed. Advanced algorithms for controlling the pressure in an airtight cabin are analyzed and literature on this topic is surveyed. The work of a Russian author that describes optimal control based on Pontryagin’s maximum principle is examined. The works of foreign authors on fuzzy PID-controller, L1-adaptive controller and other methods of adaptive pressurization are analyzed and brief results of these works are presented. The performed analysis indicates the need to use new methods and approaches to the synthesis of automatic pressure control systems for various types of aircraft. One of the most promising solutions is the use of adaptive regulators. The relevance of developing a virtual testing environment to reduce the cost of full-scale testing is shown.

New results on an electropneumatic active seat suspension system

2000 ◽  
Vol 214 (5) ◽  
pp. 533-544 ◽  
Author(s):  
G. J. Stein
Keyword(s):  
Vibration Control ◽  
Control Valve ◽  
Pressure Control ◽  
Random Excitation ◽  
Vertical Vibration ◽  
Flow Control Valve ◽  
Heavy Vehicles ◽  
Seat Suspension ◽  
Pressure Control Valve ◽  
Vibration Compensation

A vibration control system with an air spring as the actuator and proportional electropneumatic control has been developed at the Institute of Materials and Machine Mechanics, Bratislava. As the electropneumatic transducer, a proportional pressure control valve is used in contrast to the previously used proportional flow control valve. The vibration control is facilitated by a combination of a ‘sky hook’ feedback loop and a feedforward loop working on the so-called ‘sky cloud’ principle, compensating base vertical vibration. Good agreement between simulation results and measurement on a laboratory dummy system was observed. The dummy system was also subjected to narrow-band random excitation, prescribed for standardized laboratory tests of driver's seats. The improvement in driver's seat vibration control properties owing to the feedforward vibration compensation is 2.5-fold, i.e. by 8 dB in comparison with ‘sky hook’ feedback damping only. The system could be used for vibration control in automotive applications, especially for vehicles with an unsprung chassis (earth-moving machines, wheeled tractors) and in the heavy vehicles sector.

An Investigation Into the Characteristics of a Two Dimensional “2D” Flow Control Valve

2001 ◽  
Vol 124 (1) ◽  
pp. 214-220 ◽  
Author(s):  
J. Ruan ◽  
R. Burton ◽  
P. Ukrainetz
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
Structural Parameters ◽  
Control Valve ◽  
Favorable Effect ◽  
Flow Control Valve ◽  
Two Dimensional ◽  
System Pressure ◽  
Hydrostatic Force ◽  
2D Flow

In hydraulic servo systems, a pilot stage is often used to reduce the influence of Bernoulli’s forces and frictional forces when trying to accurately position a spool. A unique pilot controlled valve (defined as a two dimensional or “2D” flow control valve), which utilizes both rotary and linear motions of a single spool, is presented. The rotary motion uses a spiral groove in the sleeve combined with high and low pressure holes on the spool land to control the pressure in the spool chamber, while the linear motion of the spool is actuated by a hydrostatic force. Both linear theory and numerical simulation are adopted in the investigation of the characteristics of the valve. A criterion for stability is established from a linearized model of the valve. The analysis establishes the effects that certain structural parameters have on the valve’s static and dynamic characteristics. Special experimental procedures were designed to obtain properties such as mechanical stiffness, leakage flow rate, and dynamic response under different structural parameters and system pressure. It was shown that the leakage through the spool-sleeve clearance had a favorable effect on the valve stability. Theoretical and experimental results show that it is necessary to establish a balance between the static and dynamic performance in establishing appropriate structural parameters. It is also shown that the 2D flow control valve can demonstrate a high speed of response, while maintaining the pilot flow rate at a low level.

An Investigation Into the Characteristics of a “2D” Flow Control Valve

2000 ◽  
Author(s):  
J. Ruan ◽  
R. Burton ◽  
P. Ukrainetz
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
High Speed ◽  
Structural Parameters ◽  
Control Valve ◽  
Favorable Effect ◽  
Flow Control Valve ◽  
System Pressure ◽  
Hydrostatic Force ◽  
2D Flow

Abstract In hydraulic servo systems, a pilot stage is often used to reduce the influence of Bernoulli’s forces and frictional forces when trying to accurately position a spool. A unique pilot controlled valve, (defined as a “2D” flow control valve), which utilizes both rotary and linear motions of a single spool, is presented. The rotary motion uses a spiral groove in the sleeve combined with high and low pressure holes on the spool land to control the pressure in the spool chamber, while the linear motion of the spool is actuated by a hydrostatic force. Both linear theory and numerical simulation are adopted in the investigation of the characteristics of the valve. A criterion for stability is established from a linearized model of the valve. The analysis establishes the effects that certain structural parameters have on the valve’s static and dynamic characteristics. Special experimental procedures were designed to obtain properties such as mechanical stiffness, leakage flow rate, and dynamic response under different structural parameters and system pressure. It was shown that the leakage through the spool-sleeve clearance had a favorable effect on the valve stability. Theoretical and experimental results show that it is necessary to establish a balance between the static and dynamic performance in establishing appropriate structural parameters. It is also shown that the 2D flow control valve can demonstrate a high speed of response, while maintaining the pilot flow rate at a low level.

Modeling and Stability of a Hydraulic Load-Sensing Pump With Investigation of a Hard Nonlinearity in the Pump Displacement Control System

2014 ◽  
Author(s):  
Zachary D. Wagner ◽  
Roger Fales
Keyword(s):  
Control System ◽  
Stability Analysis ◽  
Flow Control ◽  
Control Valve ◽  
Pressure Control ◽  
Flow Control Valve ◽  
Pump System ◽  
Load Sensing ◽  
Pressure Control System ◽  
The Stability

Certain types of Load-sensing (LS) pumps utilize a hydro-mechanical control system designed to regulate the pressure difference, or margin pressure, between the inlet and outlet of a flow control valve. With a constant margin pressure, predictable flow control can be achieved by controlling the orifice area of the flow control valve. In this work, the stability of the pressure control system will be investigated. A combination of linear analysis and nonlinear analysis is employed to assess the stability of a particular LS pump system. Among many nonlinearities present in the hydro-mechanical system, of particular interest is the saturation inherent in the actuator that is used to displace the pump swash plate and the saturation within the 3-way spool valve that permits flow to reach the actuator. This saturation nonlinearity has been isolated from the rest of the system to enable stability analysis. Analysis of model characteristics is used to make conclusions about the stability of the system consisting of interconnected linear and nonlinear portions. The stability analysis is compared to results obtained through a simulation study using a nonlinear model based on first principles.

Multidisciplinary Design Optimization of a High-Flow Control Valve

2013 ◽  
Vol 300-301 ◽  
pp. 1454-1457 ◽  
Author(s):  
Fang Cao ◽  
Yong Wang
Keyword(s):  
Flow Control ◽  
Design Optimization ◽  
Multidisciplinary Design Optimization ◽  
Control Valve ◽  
Pressure Control ◽  
High Flow ◽  
Field Analysis ◽  
Multidisciplinary Design ◽  
Practical Significance ◽  
Flow Control Valve

According to the real structure and work condition of a high-flow gas pressure control valve used in recycling generating electricity project, a multidisciplinary design optimization (MDO) model is set up. Taking the structure and flow field analysis results as designing criterion, the MDO framework is put forward, which realizing the integration of multidisciplinary and two physical fields of control valve. To ensure that the gas transmission capacity which is the design prerequisite, the optimization takes reducing noise of control valve as system goal, while the valve wall thickness and flow velocity are decreased. And the Reynolds number, stress intensity and body total weight are also meet requirements. From the standpoint of fluid and structure, to realize MDO is of great practical significance for advancing research level of high-flow control valves.

Adaptive Control for Uncertain Hysteretic Systems

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Xiaotian Zou ◽  
Jie Luo ◽  
Chengyu Cao
Keyword(s):  
Adaptive Control ◽  
Linear Time ◽  
Adaptive Controller ◽  
Time Varying ◽  
Performance Bounds ◽  
L1 Adaptive Control ◽  
Hysteretic Systems ◽  
Time Varying Parameters ◽  
L1 Adaptive Controller ◽  
Uniformly Bounded

This paper presents an approach to use the L1 adaptive controller for a class of uncertain systems in the presence of unknown Preisach-type hysteresis in input, unknown time-varying parameters, and unknown time-varying disturbances. The hysteresis operator can be transformed into an equivalent linear time-varying (LTV) system with uncertainties, which means that the effect of the hysteresis can be considered as general uncertainties to the system. Without constructing the inverse hysteresis function, the L1 adaptive control is used to handle the uncertainties introduced by the hysteresis, as well as system dynamics. The adaptive controller presented in this paper ensures uniformly bounded transient and tracking performance for uncertain hysteretic systems. The performance bounds can be systematically improved by increasing the adaptation rate. Simulation results with Preisach-type hysteresis are provided to verify the theoretical findings.

Pressure Control of the Proportional Directional Control Valve Test Rig Based on the Fuzzy Proportional-Integral-Double-Integral Controller

2017 ◽  
Author(s):  
Wenzhuo Shi ◽  
Jianhua Wei ◽  
Jinhui Fang ◽  
Mingjie Li ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Performance Test ◽  
Control Valve ◽  
Pressure Control ◽  
Flow Control Valve ◽  
Test Rig ◽  
Double Integral ◽  
Relief Valve ◽  
Proportional Integral ◽  
Directional Control

The pressure drop needs to be kept constant in the flow rate/input signal performance test of proportional directional control (PDC) valve. In general, the control of valve pressure drop is implemented by regulating the relief valve or flow control valve that located between port A and port B of the PDC valve. But in this study, the load of the test valve is fixed and the stable pressure drop is obtained by changing the proportional relief valve which is placed in the inlet of the PDC valve. Then the mathematical model of the test rig and several controllers are established based on this idea. To be specific, proportional-integral (P-I) controller, proportional-integral-double-integral (P-I-II) controller, and fuzzy proportional-integral-double-integral (FP-I-II) controller are all applied to stabilize the pressure drop in this study. And the FP-I-II controller with compensation (FP-I-II-WC) is proved to be the best for this work both in the simulation and the actual experiment.

scholarly journals Performance Evaluation of Stewart-Gough Flight Simulator Based on L1 Adaptive Control

2021 ◽  
Vol 11 (7) ◽  
pp. 3288
Author(s):  
Jiangwei Zhao ◽  
Dongsu Wu ◽  
Hongbin Gu
Keyword(s):  
Adaptive Controller ◽  
Simulation System ◽  
Flight Simulation ◽  
Flight Simulator ◽  
Transient Performance ◽  
Pass Filter ◽  
Low Pass Filter ◽  
L1 Adaptive Control ◽  
Highly Nonlinear ◽  
L1 Adaptive Controller

In the design of the six degrees of freedom (6-DOF) flight simulation system, the unmodeled dynamic, transient performance and steady-state performance of the system are generally concerned. Considering that the model of flight simulation system is highly nonlinear and requires high response speed and high stability, this paper applies L1 adaptive controller to the control of flight simulation platform. The controller has a low-pass filter in feedback loop to avoid high frequencies in the control signals, and the required transient performance can be enhanced by increasing the adaptive gain, which can improve the transient, stability, and smoothness of the flight simulator platform. The performance of the L1 adaptive controller is obtained by comparison with the traditional model reference adaptive controller (MRAC). In addition to maintaining the good transient response of MRAC, the L1 adaptive controller improves the stability of the system. The output amplitude of the actuator is reduced by 39.95%, which effectively reduces the performance requirements of the actuator. Some additional experimental evaluations are carried out to show the performance of the controller.

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