scholarly journals Adaptive Fixed-Time Terminal Sliding Mode Control on SE(3) for Coupled Spacecraft Tracking Maneuver

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Kejie Gong ◽  
Ying Liao ◽  
Yong Wang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Fixed Time ◽  
Control Law ◽  
Terminal Sliding Mode Control ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Inertia Parameters ◽  
Spacecraft Tracking

In this paper, a reaching law-based adaptive fixed-time terminal sliding mode control law, which is used for coupled spacecraft tracking maneuver in the presence of large inertia parametric uncertainties and external disturbances, is proposed. The coupled 6-DOF kinematics and dynamics for spacecraft motion are modeled on Lie group SE(3). The relative configuration is expressed by a local coordinate (exponential coordinate) of SE(3). In order to estimate the inertia parameters and external disturbances, we also propose a novel adaptive update law, which can make the control law be applied without the inertia parameters of the spacecraft a priori. Fixed-time convergence property of the closed-loop feedback system is proved in the framework of Lyapunov. Numerical simulations are performed to demonstrate the performances of the proposed control scheme for coupled spacecraft tracking maneuver.

scholarly journals Design of Composite Disturbance Observer and Continuous Terminal Sliding Mode Control for Piezoelectric Nanopositioning Stage

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2242
Author(s):  
Pengyu Qiao ◽  
Jun Yang ◽  
Chen Dai ◽  
Xi Xiao
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Accurate Estimation ◽  
Terminal Sliding Mode Control ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Composite Control ◽  
Mode Control

The nonlinearities of piezoelectric actuators and external disturbances of the piezoelectric nanopositioning stage impose great, undesirable influences on the positioning accuracy of nanopositioning stage systems. This paper considers nonlinearities and external disturbances as a lumped disturbance and designs a composite control strategy for the piezoelectric nanopositioning stage to realize ultra-high precision motion control. The proposed strategy contains a composite disturbance observer and a continuous terminal sliding mode controller. The composite disturbance observer can estimate both periodic and aperiodic disturbances so that the composite control strategy can deal with the disturbances with high accuracy. Meanwhile, the continuous terminal sliding mode control is employed to eliminate the chattering phenomenon and speed up the convergence rate. The simulation and experiment results show that the composite control strategy achieves accurate estimation of different forms of disturbances and excellent tracking performance.

Self-tuning fuzzy nonsingular proportional-integral-derivative type fast terminal sliding mode control for robotic manipulator in the presence of backlash hysteresis

2021 ◽  
pp. 014233122110133
Author(s):  
Zeeshan Anjum ◽  
Hui Zhou ◽  
Yu Guo
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Proportional Integral Derivative ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Proportional Integral ◽  
Mode Control ◽  
Fast Terminal Sliding Mode ◽  
Self Tuning

The external disturbances and backlash hysteresis kind of nonlinearity present in the manipulator system can greatly affect the tracking performance of the system. In order to undo the effects of these external disturbances and backlash hysteresis, a robust controller is established based on the integration of self-tuning fuzzy nonsingular proportional-integral-derivative (PID) type fast terminal sliding mode control and time delay estimation (TDE). In this paper, TDE plays the part of estimating the unknown dynamics of the robotic manipulator and nonsingular PID type fast terminal sliding mode control in which the gains of PID are tuned using fuzzy logic system to get multiple beneficial characteristics, such as lower steady-state error, finite-time convergence and little chattering. In addition, the derivative of unknown dynamics that is considered to be bounded is dealt by utilizing the adaptive technique. Moreover, Lyapunov theorem is used to study the overall stability of the system. Finally, a comparative study in terms of trajectory tracking has been carried out between the proposed controller and other existing advanced control approaches using PUMA560 robot in order to verify the effectiveness of the proposed controller in the presence of external disturbances and bacsklash hysteresis.

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