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

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.

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

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256049
Author(s):  
Nadia Sultan ◽  
Asif Mahmood Mughal ◽  
Muhammad Najam ul Islam ◽  
Fahad Mumtaz Malik

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.


Author(s):  
Kada Boureguig ◽  
Abdellah Mansouri ◽  
Ahmed Chouya

<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>


Sign in / Sign up

Export Citation Format

Share Document