Robust Control Research for AUV Trajectory Control System

2011 ◽  
Vol 148-149 ◽  
pp. 93-96
Author(s):  
Juan Li ◽  
Xin Qian Bian ◽  
Hua Sheng Xiong ◽  
Hong Jian Wang

A robust trajectory control problem for an underactuated AUV with parameter uncertainties and external disturbances was considered. The trajectory control was decomposed in the horizontal plane and vertical plane. Based on the robust theory, the AUV model for heading control was proposed, and the heading controller was designed. The simulated results show that the method can effectively overcome disturbances of constant ocean currents to ensure the precision track.

2016 ◽  
Vol 40 (2) ◽  
pp. 591-605 ◽  
Author(s):  
Babak Baghi ◽  
Mansour Kabganian ◽  
Reza Nadafi ◽  
Ehsan Arabi

In this paper, after complete modelling of a flexible satellite equipped with a control moment gyroscope (CMG) actuator, it is shown that a PD-like controller can globally asymptotically stabilize this satellite by using Lyapunov’s direct method. Despite the simplicity, simulations show that the controller can stabilize the flexible satellite in a three-axis manoeuvre even in the presence of external disturbances. Then, using a non-linear variable gains PD controller, which only uses angular velocity of the rigid body and the attitude parameters as the inputs, the performance of the control system is improved in some important aspects such as reducing maximum control torque, reducing maximum peak of deflection of the appendages and increasing robustness of the controller against the orbital disturbances. In addition, locally asymptotically stability of the non-linear variable gain PD controller is guaranteed using a novel Lyapunov candidate function. Considering the difficulty in measuring the appendages’ deflection and the primarily existence of parameter uncertainties, and as this controller is independent of changes in these parameters, such a control system is very useful and applicable. In order to validate the system’s mathematical model and the control system performance, an exact model of the satellite is constructed in the ADAMS/View software that is linked to the MATLAB software. The efficacy of the proposed approach is demonstrated by several numerical examples.


Author(s):  
Ni Dan ◽  
Jingfang Wang

According to movement balancing and position control problem of Self Balancing Two Wheeled Robot, a method based on H∞ Robust Control was proposed. We apply it onto the MIMO nonlinear model of robot, and simulated it in the MATLAB environment The simulation results shows that the robot can be balanced in fixed position well by this method, and also it have the ability to anti interference.


Author(s):  
Bui Duc Hong Phuc ◽  
Sang-Do Lee ◽  
Sam-Sang You ◽  
Natwar Singh Rathore

The supercavitating vehicle can quickly become unstable under the influence of the planing force and external disturbances due to waves and currents. The planing force demonstrates nonlinear characteristics which can be described by the vehicle state variables. Strict standards for maneuvering strategy are required for high-speed vehicles to operate, particularly guidance, navigation, and control of underwater maneuver. In reality, the high-speed supercavitating vehicle dynamics present various control issues and challenges. This article proposes the nonlinear robust control synthesis to manipulate the vertical plane of the high-speed supercavitating vehicle against the planing force or parameter variations as well as external disturbances. The control synthesis is implemented by solving an algebraic Riccati equation at each iteration of the control algorithm with the updated system states, which is a so-called state-dependent Riccati equation. The control loops in the dive-plane satisfy an [Formula: see text] performance criterion that can reject external disturbances with perturbations. Simulation results show that the controlled vehicle system guarantees fast transient responses with steady-state performance. Besides, the proposed controller can eliminate up to 62% of disturbances and provides the robust performance against large planing force and parametric uncertainties. This new vehicle technology with active controller offers the potential strategy of higher speed and higher maneuverability solutions for various purposes of underwater maneuvering.


2007 ◽  
Vol 4 (4) ◽  
pp. 137-147 ◽  
Author(s):  
Mugdha S. Naik ◽  
Sahjendra N. Singh

This article considers the control of a biorobotic autonomous underwater vehicle (BAUV) in the yaw plane using biologically inspired oscillatory pectoral-like fins of marine animals. The fins are assumed to be oscillating harmonically with a combined linear (sway) and angular (yaw) motion producing unsteady forces, which are used for fish-like control of BAUVs. Manoeuvring of the BAUV in the yaw plane is accomplished by altering the bias (mean) angle of the angular motion of the fin. For the derivation of the adaptive control system, it is assumed that the physical parameters, the hydrodynamic coefficients, and the fin force and moment are not known. A direct adaptive sampled-data control system for the trajectory control of the yaw-angle using only yaw-angle measurement is derived. The parameter adaptation law is based on the normalised gradient scheme. Simulation results for the set point control, sinusoidal trajectory tracking and turning manoeuvres are presented, which show that the control system accomplishes precise trajectory control in spite of the parameter uncertainties.


Author(s):  
Jiangpeng Song ◽  
Di Zhou ◽  
Guangli Sun

The line-of-sight (LOS) kinematics and dynamics of a mirror-stabilized platform are derived using the virtual mass stabilization method. Accounting for the coupled and nonlinear kinematics and dynamics, the uncertainty of external disturbances, and the actuator input saturation in the mirror-stabilized platform, a modified adaptive robust control (ARC) scheme is proposed based on the command filtered method and the extended state observer (ESO). The command-filtered approach is used to ensure the stability and tracking performance of the adaptive control system under the input saturation. In the proposed scheme, the ESO is designed to observe the modeling error and unknown external disturbances. The stability of the control system is proved using the Lyapunov method. Simulation results and experimental results proved that the proposed control scheme can effectively reduce the occurrence of input saturation, attenuate the effect of unknown disturbances, and improve the position tracking accuracy.


2021 ◽  
pp. 1-12
Author(s):  
Tomotaka Saruya ◽  
Shuji Fujita ◽  
Ryo Inoue

Abstract Polycrystalline ice is known to exhibit macroscopic anisotropy in relative permittivity (ɛ) depending on the crystal orientation fabric (COF). Using a new system designed to measure the tensorial components of ɛ, we investigated the dielectric anisotropy (Δɛ) of a deep ice core sample obtained from Dome Fuji, East Antarctica. This technique permits the continuous nondestructive assessment of the COF in thick ice sections. Measurements of vertical prism sections along the core showed that the Δɛ values in the vertical direction increased with increasing depth, supporting previous findings of c-axis clustering around the vertical direction. Analyses of horizontal disk sections demonstrated that the magnitude of Δɛ in the horizontal plane was 10–15% of that in the vertical plane. In addition, the directions of the principal axes of tensorial ɛ in the horizontal plane corresponded to the long or short axis of the elliptically elongated single-pole maximum COF. The data confirmed that Δɛ in the vertical and horizontal planes adequately indicated the preferred orientations of the c-axes, and that Δɛ can be considered to represent a direct substitute for the normalized COF eigenvalues. This new method could be extremely useful as a means of investigating continuous and depth-dependent variations in COF.


Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7084
Author(s):  
Song Kang ◽  
Yongfeng Rong ◽  
Wusheng Chou

In this paper, an output-feedback fuzzy adaptive dynamic surface controller (FADSC) based on fuzzy adaptive extended state observer (FAESO) is proposed for autonomous underwater vehicle (AUV) systems in the presence of external disturbances, parameter uncertainties, measurement noises and actuator faults. The fuzzy logic system is incorporated into both the observers and controllers to improve the adaptability of the entire system. The dynamics of the AUV system is established first, considering the external disturbances and parameter uncertainties. Based on the dynamic models, the ESO, combined with a fuzzy logic system tuning the observer bandwidth, is developed to not only adaptively estimate both system states and the lumped disturbances for the controller, but also reduce the impact of measurement noises. Then, the DSC, together with fuzzy logic system tuning the time constant of the low-pass filter, is designed using estimations from the FAESO for the AUV system. The asymptotic stability of the entire system is analyzed through Lyapunov’s direct method in the time domain. Comparative simulations are implemented to verify the effectiveness and advantages of the proposed method compared with other observers and controllers considering external disturbances, parameter uncertainties and measurement noises and even the actuator faults that are not considered in the design process. The results show that the proposed method outperforms others in terms of tracking accuracy, robustness and energy consumption.


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