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.

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.

Robust active disturbance attenuation control of an uncertain quadrotor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nigar Ahmed ◽  
Ajeet kumar Bhatia ◽  
Syed Awais Ali Shah
Keyword(s):  
Control Algorithm ◽  
Sliding Mode ◽  
The State ◽  
Disturbance Attenuation ◽  
State Variables ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Highly Nonlinear ◽  
The Stability

PurposeThe aim of this research is to design a robust active disturbance attenuation control (RADAC) technique combined with an extended high gain observer (EHGO) and low pass filter (LPF).Design/methodology/approachFor designing a RADAC technique, the sliding mode control (SMC) method is used. Since the standard method of SMC exhibits a chattering phenomenon in the controller, a multilayer sliding mode surface is designed for avoiding the chattering. In addition, to attenuate the unwanted uncertainties and disturbances (UUDs), the techniques of EHGO and LPF are deployed. Besides acting as a patch for disturbance attenuation, the EHGO design estimates the state variables. To investigate the stability and effectiveness of the designed control algorithm, the stability analysis followed by the simulation study is presented.FindingsThe major findings include the design of a chattering-free RADAC controller based on the multilayer sliding mode surface. Furthermore, a criterion of integrating the LPF scheme within the EHGO scheme is also developed to attenuate matched and mismatched UUDs.Practical implicationsIn practice, the quadrotor flight is opposed by different kinds of the UUDs. And, the model of the quadrotor is a highly nonlinear underactuated model. Thus, the dynamics of the quadrotor model become more complex and uncertain due to the additional UUDs. Hence, it is necessary to design a robust disturbance attenuation technique with the ability to estimate the state variables and attenuate the UUDs and also achieve the desired control objectives.Originality/valueDesigning control methods to attenuate the disturbances while assuming that the state variables are known is a common practice. However, investigating the uncertain plants with unknown states along with the disturbances is rarely taken in consideration for the control design. Hence, this paper presents a control algorithm to address the issues of the UUDs as well as investigate a criterion to reduce the chattering incurred in the controller due to the standard SMC algorithm.

scholarly journals Neural NetworkL1Adaptive Control of MIMO Systems with Nonlinear Uncertainty

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hong-tao Zhen ◽  
Xiao-hui Qi ◽  
Jie Li ◽  
Qing-min Tian
Keyword(s):  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Adaptive Controller ◽  
Rbf Neural Networks ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Input Multiple Output ◽  
Low Pass ◽  
Nonlinear Uncertainties

An indirect adaptive controller is developed for a class of multiple-input multiple-output (MIMO) nonlinear systems with unknown uncertainties. This control system is comprised of anL1adaptive controller and an auxiliary neural network (NN) compensation controller. TheL1adaptive controller has guaranteed transient response in addition to stable tracking. In this architecture, a low-pass filter is adopted to guarantee fast adaptive rate without generating high-frequency oscillations in control signals. The auxiliary compensation controller is designed to approximate the unknown nonlinear functions by MIMO RBF neural networks to suppress the influence of uncertainties. NN weights are tuned on-line with no prior training and the project operator ensures the weights bounded. The global stability of the closed-system is derived based on the Lyapunov function. Numerical simulations of an MIMO system coupled with nonlinear uncertainties are used to illustrate the practical potential of our theoretical results.

scholarly journals A fast L1 adaptive constrained back-stepping controller using barrier Lyapunov function for anuncertain submersible vehicle

2021 ◽  
Author(s):  
Hossein Ahmadian ◽  
Mehdi Arefi ◽  
Alireza Khayatian ◽  
Allahyar Montazeri
Keyword(s):  
Adaptive Control ◽  
Lyapunov Function ◽  
Trajectory Tracking ◽  
Tracking Error ◽  
Control Technique ◽  
Remotely Operated Vehicle ◽  
Pass Filter ◽  
Low Pass Filter ◽  
L1 Adaptive Control ◽  
Barrier Lyapunov Function

Abstract In this paper, a new L1 adaptive back-stepping controller based on the barrier Lyapunov function (BLF) is proposed to respect the position and velocity constraints usually imposed in designing Euler-Lagrange systems. The purpose of this investigation is to improve different aspects of a conventional L1 adaptive control. More specifically, the modified controller has a lower complexity by removing the low-pass filter from the design procedure. The performance of the controller is also enhanced by having a faster convergence speed and increased robustness against nonlinear uncertainties and disturbances arising in practical applications. The proposed scheme is evaluated on two different Euler-Lagrange systems, i.e. a 6-DOF remotely operated vehicle (ROV) and a single-link manipulator. The results for the new back-stepping design are assessed in both scenarios in terms of settling time, percentage of overshoot, and trajectory tracking error. The results confirm that both tracking and state estimation errors for position and velocity outputs outperform the standard L1 adaptive control technique. The results also demonstrate the high performance of the proposed approach in removing the matched nonlinear time-varying disturbances and dynamic uncertainties and a good trajectory tracking despite the uncertainty on the input gain of the system.

Sound Analysis and Synthesis for Audio Simulation System of Flight Simulator

2013 ◽  
Vol 748 ◽  
pp. 708-712 ◽  
Author(s):  
Xiao Wei Sheng ◽  
Jun Wei Han ◽  
Ming Hui Hao
Keyword(s):  
Linear Prediction ◽  
Simulation System ◽  
Flight Simulation ◽  
Pilot Training ◽  
Flight Simulator ◽  
Sound Sources ◽  
Analysis And Synthesis ◽  
Development Technology ◽  
Recording Conditions ◽  
Preparation Step

Through simulating the feelings of vision, hearing, motion and force during flight, the flight simulator can build a realistic flight environment on the ground. Therefore, Flight simulators have an important role in pilot training field. Audio simulation system is a key component of the flight simulator, it has direct impact on the realism and immersion of flight simulation. In this paper, we introduced the development procedure of audio simulation system shortly. Software implementation and its key development technology were mainly focused for expressing the necessity of extracting sound sources from original cockpit recordings. Based on the development method and practical recording conditions, we dicussed sound short-time Fourier analysis and synthesis technology, and sound linear prediction analysis and synthesis technology in detail. The objective of using these technologies was to extract sound sources from original recordings and this was also the preparation step of sound simulation.

scholarly journals Dynamic Surface Control and Its Application to Lateral Vehicle Control

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Bongsob Song ◽  
J. Karl Hedrick ◽  
Yeonsik Kang
Keyword(s):  
Nonlinear Systems ◽  
Dynamic Surface Control ◽  
Vehicle Control ◽  
Linear Matrix ◽  
Automated Driving ◽  
Dynamic Surface ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Surface Control ◽  
Highly Nonlinear

This paper extends the design and analysis methodology of dynamic surface control (DSC) in Song and Hedrick, 2011, for a more general class of nonlinear systems. When rotational mechanical systems such as lateral vehicle control and robot control are considered for applications, sinusoidal functions are easily included in the equation of motions. If such a sinusoidal function is used as a forcing term for DSC, the stability analysis faces the difficulty due to highly nonlinear functions resulting from the low-pass filter dynamics. With modification of input variables to the filter dynamics, the burden of mathematical analysis can be reduced and stability conditions in linear matrix inequality form to guarantee the quadratic stability via DSC are derived for the given class of nonlinear systems. Finally, the proposed design and analysis approach are applied to lateral vehicle control for forward automated driving and backward parallel parking at a low speed as well as an illustrative example.

A study of PID and L1 adaptive control for automatic balancing of a spacecraft three-axis simulator

2018 ◽  
Vol 11 (2) ◽  
pp. 269-284
Author(s):  
Bing Hua ◽  
Lin Chen ◽  
Yunhua Wu ◽  
Zhiming Chen
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Large Angle ◽  
High Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
L1 Adaptive Control ◽  
Automatic Balancing ◽  
Disturbance Torque

Purpose The three-axis simulator relies on the air film between the air bearing and the bearing seat to achieve weightlessness and the frictionless motion condition, which is essential for simulating the micro-disturbance torque of a satellite in outer space. However, at the beginning of the experiment, the disturbance torque caused by the misalignment between the center of gravity of the simulator and the center of rotation of the bearing is the most important factor restricting the use of the space three-axis simulator. In order to solve this problem, it is necessary to set the balance adjustment system on the simulator to compensate the disturbance torque caused by the eccentricity. The paper aims to discuss these issues. Design/methodology/approach In this paper, a study of L1 adaptive automatic balancing control method for micro satellite with motor without other actuators is proposed. L1 adaptive control algorithm adds the low-pass filter to the control law, which in a certain sense to reduce the high-frequency signal and speed up the response time of the controlled system. At the same time, by estimating the adaptive parameter uncertainty in object, the output error of the state predictor and the controlled object can be stabilized under Lyapunov condition, and the robustness of the system is also improved. The automatic balancing method of PID is also studied in this paper. Findings Through this automatic balancing mechanism, the gravity disturbance torque can be effectively reduced down to 10−6 Nm, and the automatic balancing time can be controlled within 7 s. Originality/value This paper introduces an automatic balancing mechanism. The experimental results show that the mechanism can greatly improve the convergence speed while guaranteeing the control accuracy, and ensuring the feasibility of the large angle maneuver of spacecraft three-axis simulator.

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 The Investigation on L 1 Adaptive Control of the Tilt-Rotor Aircraft

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Quanlong Chen ◽  
Shanyong Zhao ◽  
Ke Lu ◽  
Senkui Lu ◽  
Chunsheng Liu ◽  
...  
Keyword(s):  
Control System ◽  
Adaptive Design ◽  
Reference Signal ◽  
Engineering Application ◽  
Adaptive Controller ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Tilt Rotor ◽  
Conversion Mode ◽  
Flight Dynamics Model

Considering the uncertainty of the flight dynamics model of the tilt-rotor aircraft in different flight modes, an L 1 adaptive controller for full flight modes control system of tilt-rotor aircraft is designed. Taking advantage of the separation of robustness and adaptive design of the L 1 adaptive controller, adaptive gain, and low-pass filter are designed to achieve the desired control performance and meet the requirements of flight quality. The simulations of XV-15 tilt-rotor aircraft in helicopter mode and airplane mode are carried out. Then, the simulation of conversion mode is further carried out. The results show that the tilt-rotor aircraft can track the reference signal well under the L 1 control system. In addition, the changes of states as well as controls in conversion mode flight are quite smooth which is very meaningful for engineering application.

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