Composite nonlinear extended state observer and its application to unmanned ground vehicles

2021 ◽  
Vol 109 ◽  
pp. 104731
Author(s):  
Haoyu Wang ◽  
Zhiqiang Zuo ◽  
Yijing Wang ◽  
Hongjiu Yang ◽  
Shaoping Chang
Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1651 ◽  
Author(s):  
Amjad J. Humaidi ◽  
Ibraheem Kasim Ibraheem

In this paper, a novel finite-time nonlinear extended state observer (NLESO) is proposed and employed in active disturbance rejection control (ADRC) to stabilize a nonlinear system against system’s uncertainties and discontinuous disturbances using output feedback based control. The first task was to aggregate the uncertainties, disturbances, and any other undesired nonlinearities in the system into a single term called the “generalized disturbance”. Consequently, the NLESO estimates the generalized disturbance and cancel it from the input channel in an online fashion. A peaking phenomenon that existed in linear ESO (LESO) has been reduced significantly by adopting a saturation-like nonlinear function in the proposed nonlinear ESO (NLESO). Stability analysis of the NLEO is studied using finite-time Lyapunov theory, and the comparisons are presented over simulations on permanent magnet DC (PMDC) motor to confirm the effectiveness of the proposed observer concerning LESO.


Author(s):  
Chao Lai ◽  
Weihong Wang ◽  
Zhenghua Liu ◽  
Zheng Ma

A neuro-adaptive fast terminal sliding-mode dynamic surface control method based on a finite-time stable nonlinear extended state observer is applied to integrated guidance and control design for skid-to-turn missile attacking a ground maneuvering target with terminal angle constraints. A three-dimensional integrated guidance and control design model against a maneuvering target for skid-to-turn missile is established without the assumption that the missile velocity vector and the line of sight coincide with each other. The non-singular fast terminal sliding surface is applied to construct the first error surface of dynamic surface control and the first virtual control law is designed to guarantee hitting accuracy with desired terminal angles. The finite-time stable nonlinear extended state observer is designed separately to estimate uncertainties in the system. And the neuro-adaptive technique is applied to compensate estimation errors of nonlinear extended state observer by training a three-layer feedforward neural network online. Synthesizing all of above, a neuro-adaptive fast terminal sliding-mode dynamic surface control based on nonlinear extended state observer is derived on Lyapunov stability theory, which guarantees stability of the system. Finally, the numerical simulations are conducted to demonstrate the effectiveness of the proposed three-dimensional integrated guidance and control scheme.


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