scholarly journals L1 Adaptive Loss Fault Tolerance Control of Unmanned Hypersonic Aircraft with Elasticity

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 176
Author(s):  
Zhaoying Li ◽  
Shuai Shi
Keyword(s):  
Fault Tolerance ◽  
Pid Controller ◽  
Control Method ◽  
Adaptive Controller ◽  
Hypersonic Vehicle ◽  
L1 Adaptive Control ◽  
Hypersonic Aircraft ◽  
L1 Adaptive Controller ◽  
Tolerance Control ◽  
Loss Of Actuator Effectiveness

This paper investigates the fault tolerance control of hypersonic aircrafts with L1 adaptive control method in the presence of loss of actuator effectiveness fault. The hypersonic model considers the uncertainties caused by the features of nonlinearities and couplings. Elasticity is taken into account in hypersonic vehicle modeling which makes the model more accurate. A velocity L1 adaptive controller and an altitude L1 adaptive controller are designed to control flexible hypersonic vehicle model with actuator loss fault. A PID controller is designed as well for comparison. Finally, the simulation results are used to analyze the effectiveness of the controller. Compared to the results of PID controller, L1 controllers have better performance.

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.

scholarly journals Improved Neutral-Point Voltage-Shifting Strategy for Power Balancing in Cascaded NPC/H-Bridge Inverter

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 167 ◽  
Author(s):  
Jin-Wook Kang ◽  
Seung-Wook Hyun ◽  
Jae-Ok Ha ◽  
Chung-Yuen Won
Keyword(s):  
Phase Equilibrium ◽  
Fault Tolerance ◽  
Output Power ◽  
Control Method ◽  
Neutral Point ◽  
Voltage Range ◽  
Multilevel Inverters ◽  
Three Phase ◽  
Power Balancing ◽  
Tolerance Control

This paper investigates the fault-tolerance control of a multilevel cascaded NPC/H-bridge (CNHB) inverter. The fault-tolerance control method has been widely used for multilevel inverters, such as the neutral-point voltage-shifting control, which can operate for a certain period of time by compensating for the phase voltage of a faulty stack even if one stack is broken. Even though the three-phase equilibrium is maintained in the case of failure by using the conventional neutral-point voltage-shifting control, an imbalance in the output power occurs between each stack, which causes problems for maintenance and lifetime. Therefore, this paper proposes a fault-tolerance control that can maintain three-phase equilibrium in a case of stack failures and minimize power imbalances between the stacks. The problem of the conventional neutral-point voltage-shifting control is presented based on the output power. In addition, the power imbalance is improved by performing selective neutral-point voltage-shifting control according to the reference voltage range. To verify the principle and feasibility of the proposed neutral-point voltage-shifting control method, a simulation and an experiment are implemented with the CNHB inverter.

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.

scholarly journals L1 Adaptive for Aircraft Lateral Fault Tolerant Control with Actuator Failure

2019 ◽  
Vol 37 (5) ◽  
pp. 935-942
Author(s):  
Yan Zhou ◽  
Huiying Liu ◽  
Jing Li
Keyword(s):  
Control Method ◽  
Fault Tolerant ◽  
Adaptive Controller ◽  
Actuator Failure ◽  
Bounded Control ◽  
L1 Adaptive Control ◽  
Unmatched Uncertainties ◽  
Fault Mode ◽  
The Stability ◽  
Multiplicative Fault

When aircraft is laterally controlled, actuator failure may cause matched/unmatched uncertainties. In order to deal with the uncertainty, a fault-tolerant controller is designed by using L1 adaptive control method. An aircraft lateral model was established by considering faults and disturbances, the effects of the uncertainty and interference were counteracted by using L1 adaptive controller in order to ensure the rapid adaptation and robustness, and then the stability and transient performance of the closed-loop system were proven through Lyapunov method. In the case of multiplicative fault, additive fault and stuck fault, the uncertainties of model parameter were added to simulate simultaneously. Simulation results showed that the present control method in both single-fault mode and hybrid-failure mode could ensure the uniform bounded control signal and parameter estimation, effectively eliminates the effect of the faults and had the good fault tolerance and robustness.

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.

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.

scholarly journals Design of L1 Adaptive Controller for Position Control of Permanent Magnet Linear Synchronous Motor (PMLSM)

2018 ◽  
pp. 39-52
Keyword(s):  
Adaptive Control ◽  
Permanent Magnet ◽  
Position Control ◽  
Adaptive Controller ◽  
Servo Motor ◽  
Model Reference ◽  
L1 Adaptive Control ◽  
Asymptotic Tracking ◽  
L1 Adaptive Controller ◽  
Model Reference Adaptive

In the present work, the design of an L1 adaptive controller for position control of a linear servo motor for X-Y table application has been developed. The AC Permanent Magnet Linear Synchronous Servo Motor (PMLSM) is considered. A comparative study between L1 adaptive control and Model Reference Adaptive Control (MRAC) has been made. The effectiveness of the L1 adaptive controller against uncertain parameters is analyzed based on simulated results. Robustness characteristics of both L1 adaptive controller and model reference adaptive controller to different input reference signals and different structures of uncertainty have been evaluated. The L1-adaptive controller could ensure uniformly bounded transient and asymptotic tracking for input and output signals. Simulations based on MATLAB of an x-y table based on PMLSM with time-varying friction and disturbance are presented to verify the theoretical findings. The simulation results within the environment of MATLAB/SIMULINK showed that L1-adaptive controller could give better tracking performance, dynamic and steady-state characteristics, than that obtained from MRAC for considered types of input and for various structures of uncertainties.

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