scholarly journals High-gain observer-based nonlinear control scheme for biomechanical sit to stand movement in the presence of sensory feedback delays

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256049
Author(s):  
Nadia Sultan ◽  
Asif Mahmood Mughal ◽  
Muhammad Najam ul Islam ◽  
Fahad Mumtaz Malik
Keyword(s):  
Detailed Analysis ◽  
Feedback Linearization ◽  
High Gain ◽  
Control Technique ◽  
Joint Position ◽  
Neurophysiological Mechanism ◽  
Physiological Variables ◽  
Sit To Stand ◽  
High Gain Observer ◽  
Input Signals

Sit-to-stand movement (STS) is a mundane activity, controlled by the central-nervous-system (CNS) via a complex neurophysiological mechanism that involves coordination of limbs for successful execution. Detailed analysis and accurate simulations of STS task have significant importance in clinical intervention, rehabilitation process, and better design for assistive devices. The CNS controls STS motion by taking inputs from proprioceptors. These input signals suffer delay in transmission to CNS making movement control and coordination more complex which may lead to larger body exertion or instability. This paper deals with the problem of STS movement execution in the presence of proprioceptive feedback delays in joint position and velocity. We present a high-gain observer (HGO) based feedback linearization control technique to mimic the CNS in controlling the STS transfer. The HGO estimates immeasurable delayed states to generate input signals for feedback. The feedback linearization output control law generates the passive torques at joints to execute the STS movement. The H2 dynamic controller calculates the optimal linear gains by using physiological variables. The whole scheme is simulated in MATLAB/Simulink. The simulations illustrate physiologically improved results. The ankle, knee, and hip joint position profiles show a high correlation of 0.91, 0.97, 0.80 with the experimentally generated reference profiles. The faster observer dynamics and global boundness of controller result in compensation of delays. The low error and high correlation of simulation results demonstrate (1) the reliability and effectiveness of the proposed scheme for customization of human models and (2) highlight the fact that for detailed analysis and accurate simulations of STS movement the modeling scheme must consider nonlinearities of the system.

High Gain Observer for Drag Tracking in Mars Entry Longitudinal Guidance

2012 ◽  
Vol 241-244 ◽  
pp. 1374-1378
Author(s):  
Kai Wu ◽  
Hu Tao Cui ◽  
Dong Mei Ma ◽  
Ping Yuan Cui
Keyword(s):  
Model Uncertainty ◽  
Feedback Linearization ◽  
High Gain ◽  
Model Error ◽  
Guidance Law ◽  
High Gain Observer ◽  
Feedback Linearization Control ◽  
Adaptive Guidance ◽  
The Ideal

An extended high gain state and perturbation observer combined with feedback linearization was applied in drag tracking for Mars entry longitudinal guidance. The observer estimates the drag, the drag rate and the perturbation due to model uncertainty and disturbance for drag tracking. Mars entry simulation was performed to assess the performance of the adaptive guidance law. The results demonstrate that the proposed guidance law is robust to model error, and can recover the ideal performance of the feedback linearization control.

A HIGH-GAIN OBSERVER APPROACH APPLIED TO THE ROBUST FEEDBACK LINEARIZATION CONTROL

2007 ◽  
Vol 40 (20) ◽  
pp. 64-69
Author(s):  
Ebrahim Samer El'youssef ◽  
Ubirajara F. Moreno ◽  
Edson R. De Pieri ◽  
Eugênio B. Castelan Neto
Keyword(s):  
Feedback Linearization ◽  
High Gain ◽  
High Gain Observer ◽  
Feedback Linearization Control

Robust High-Gain Observer Approach to State of Charge for Lithium-Ion Batteries of Automated Guided Vehicles

2014 ◽  
Vol 536-537 ◽  
pp. 1562-1565
Author(s):  
Sung Hoon Yu ◽  
Chang Ho Hyun ◽  
Hyo Seok Kang
Keyword(s):  
Lithium Ion Batteries ◽  
Sliding Mode ◽  
Lithium Ion ◽  
Response Speed ◽  
High Gain ◽  
State Of Charge ◽  
Automated Guided Vehicles ◽  
Control Technique ◽  
Perturbation Problem ◽  
High Gain Observer

This paper introduces a robust high-gain observer based state of charge (SOC) estimator for lithium-ion batteries of automated guided vehicles (AGV) . The proposed observer scheme enhances the transient response speed and diminishes the effect of uncertainties. Furthermore, it overcomes the perturbation problem, which is caused by high gains since the proposed observer scheme adopts sliding mode control technique. In order to verify the effectiveness of the propose method, the linear RC battery model in ADVISOR is used.

scholarly journals Robust Output Feedback Control of Single-Link Flexible-Joint Robot Manipulator with Matched Disturbances Using High Gain Observer

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3252
Author(s):  
Hameed Ullah ◽  
Fahad Mumtaz Malik ◽  
Abid Raza ◽  
Naveed Mazhar ◽  
Rameez Khan ◽  
...  
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Angular Position ◽  
Output Feedback Control ◽  
High Gain ◽  
Control Technique ◽  
Flexible Joint ◽  
Position Sensing ◽  
High Gain Observer ◽  
Single Link

This article focuses on the output feedback control of single-link flexible-joint robot manipulators (SFJRMs) with matched disturbances and parametric uncertainties. Formally, four sensing elements are required to design the controller for single-link manipulators. We have designed a robust control technique for the semiglobal stabilization problem of the angular position of the link in the SFJRM system, with the availability of only a position sensing device. The sliding mode control (SMC) based output feedback controller is devised for SFJRM dynamics. The nonlinear model of SFJRM is considered to estimate the unknown states utilizing the high-gain observer (HGO). It is shown that the output under SMC using HGO-based estimated states coincides with that using original states when the gains of HGO are sufficiently high. Finally, the results are presented showing that the designed control technique works well when the SFJRM model is uncertain and matched perturbations are expected.

High-Gain Observer-Based Neural Adaptive Feedback Linearizing Control of a Team of Wheeled Mobile Robots

Robotica ◽  
2019 ◽  
Vol 38 (1) ◽  
pp. 69-87 ◽  
Author(s):  
Neda Sarrafan ◽  
Khoshnam Shojaei
Keyword(s):  
Mobile Robots ◽  
Inverse Dynamics ◽  
Actuator Saturation ◽  
High Gain ◽  
Control Technique ◽  
Wheeled Mobile Robots ◽  
Tracking Errors ◽  
High Gain Observer ◽  
The Neural Network ◽  
Adaptive Laws

SummaryThis paper addresses the neural network (NN) output feedback formation tracking control of nonholonomic wheeled mobile robots (WMRs) with limited voltage input. A desired formation is achieved based on the leader–follower strategy utilizing hyperbolic tangent saturation functions to reduce the risk of actuator saturation. The controller is developed by incorporating the high-gain observer and radial basis function (RBF) NNs using the inverse dynamics control technique. The high-gain observer is introduced to estimate velocities of the followers. The RBF NN preserves the robustness of the proposed controller against uncertain nonlinearities. The adaptive laws are also combined by a robust control term to estimate the weights of RBF NN, approximation errors, and bounds of unknown time-variant environmental disturbances. A Lyapunov-based stability analysis proves that all signals of the closed-loop system are bounded, and tracking errors are uniformly ultimately bounded. Finally, some simulations are carried out to show the effectiveness of the proposed controller for a number of WMRs.

scholarly journals Performance enhancements of DFIG wind turbine using fuzzy-feedback linearization controller augmented by high-gain observer

2020 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Kada Boureguig ◽  
Abdellah Mansouri ◽  
Ahmed Chouya
Keyword(s):  
Feedback Linearization ◽  
Fuzzy Logic Controller ◽  
Dynamic Performance ◽  
High Gain ◽  
Lyapunov Theory ◽  
Nonlinear Observer ◽  
High Gain Observer ◽  
Rotor Flux ◽  
Doubly Fed ◽  
The Stability

<span>This paper proposes a feedback linearization control of doubly fed induction generator based wind energy systems for improving decoupled control of the active and reactive powers stator. In order to enhance dynamic performance of the controller studied, the adopted control is reinforced by a fuzzy logic controller. This approach is designed without any model of rotor flux estimation. The difficulty of measuring of rotor flux is overcome by using high gain observer. The stability of the nonlinear observer is proved by the Lyapunov theory. Numerical simulations using MATLAB-SIMULINK shown clearly the robustness of the proposed control, particularly to the disturbance rejection and parametric variations compared with the conventional method.</span>

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