Consecutive Compensator in Station-Keeping of a Surface Vessel

2020 ◽  
Vol 21 (10) ◽  
pp. 566-574
Author(s):  
O. I. Borisov ◽  
A. R. Dahl ◽  
A. A. Pyrkin ◽  
F. B. Gromova ◽  
R. Skjetne
Keyword(s):  
Degrees Of Freedom ◽  
External Disturbance ◽  
High Gain ◽  
Longitudinal Motion ◽  
Station Keeping ◽  
External Disturbances ◽  
Set Up ◽  
Surface Vessel ◽  
Thrust Allocation ◽  
Three Degrees Of Freedom

This paper addresses the problem of station-keeping of a surface vessel by means of the consecutive compensator approach. The horizontal motion of the vessel is described by a dynamic model. The model is set up in vessel parallel coordinates, with three degrees of freedom: longitudinal, transverse and rotational motion. It is assumed that the vessel is fully actuated, i.e. there is a sufficient number and type of actuators and a thrust allocation system to ensure full manoeuvrability. Thus, the control can be designed with the assumption of three independent inputs and three output signals. The longitudinal motion can be considered separately, but a cross-coupling exists between the transverse and rotational kinetics. There is uncertainty both in parameters and signals, due to the vessel mass, inertia, and damping, as well as the unmeasured derivatives. The proposed control ensures station-keeping when the vessel is subjected to external disturbances. The consecutive compensator, which is based on high-gain feedback, provides robustness. Stability analysis is presented considering the cross-terms as limited disturbances. This allows proof of exponential stability. Experimental results are included from the Marine Cybernetics Laboratory (MC lab) at the Centre for Autonomous Marine Operations and Systems (A MOS) at the Norwegian University of Science and Technology (Norges teknisk-naturvitenskapelige universitet, NTNU ). Two scenarios are investigated: the scaled vessel is subjected to external disturbance, and the vessel executes the " four corner test". The experiments illustrate the applicability of the method.

scholarly journals Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xiaohui Liu ◽  
Ming Zou ◽  
Chuan Wu ◽  
Mengqi Cai ◽  
Guangyun Min ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Transmission Lines ◽  
Degrees Of Freedom ◽  
Wind Tunnel Test ◽  
Aerodynamic Coefficients ◽  
Wake Effect ◽  
Aerodynamic Coefficient ◽  
Set Up ◽  
The Stability ◽  
Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

scholarly journals A Neural Network Based Sliding Mode Control for Tracking Performance with Parameters Variation of a 3-DOF Manipulator

2019 ◽  
Vol 9 (10) ◽  
pp. 2023 ◽  
Author(s):  
Hoai-Vu-Anh Truong ◽  
Duc-Thien Tran ◽  
Kyoung Kwan Ahn
Keyword(s):  
Neural Network ◽  
Sliding Mode Control ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
External Disturbance ◽  
Robotic Manipulator ◽  
Tracking Performance ◽  
Mode Control ◽  
Tracking Motion ◽  
Three Degrees Of Freedom

The manipulator, in most cases, works in unstructured and changeable conditions. With large external variations, the demand for stability and robustness must be ensured. This paper proposes a neural network sliding mode control (NNSMC) to cope with uncertainties and improve the behavior of the robotic manipulator in the presence of an external disturbance. The proposed method is applied to the three degrees of freedom (DOF) manipulator. Some comparisons between the proposed and the conventional algorithms are given in both simulation and experiments to prove that the designed control can achieve higher accuracy in tracking motion.

Disturbance Response of Two-Link Underactuated Serial-Link Chains

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Ravi Balasubramanian ◽  
Joseph T. Belter ◽  
Aaron M. Dollar
Keyword(s):  
Degrees Of Freedom ◽  
External Disturbance ◽  
Contact Forces ◽  
Coupling Mechanism ◽  
Robotic Hands ◽  
External Disturbances ◽  
Serial Link ◽  
Disturbance Response ◽  
Actuation Mode ◽  
Coupling Mechanisms

In an attempt to improve the performance of underactuated robotic hands in grasping, we investigate the influence of the underlying coupling mechanism on the robustness of underactuated hands to external disturbance. The coupling mechanisms used in underactuated mechanisms can be divided into two main classes based on the self-adaptive transmission used to route actuation to the degrees of freedom, namely single-acting and double-acting transmissions. The kinematic coupling constraint is always active in double-acting mechanisms, while there are specific combinations of external disturbances and mechanism parameters that render the constraint inactive in single-acting mechanisms. This paper identifies unique behaviors in terms of mechanism reconfiguration and variation in grasping contact forces that result from the underactuated hand’s response to external disturbance forces and show that these behaviors are a function of the coupling mechanism, actuation mode, and contact constraints. We then present an analysis of how these behaviors influence grasping ability of the hand and discuss implications for underactuated hand design and operation.

Analytical Stability Analysis of Surface Vessel Trajectories for a Control-Oriented Model

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
Alan M. Whitman ◽  
Hashem Ashrafiuon ◽  
Kenneth R. Muske
Keyword(s):  
Stability Analysis ◽  
Degrees Of Freedom ◽  
Viscous Drag ◽  
Reduced Order ◽  
Analytical Stability ◽  
Straight Line ◽  
Vessel Motion ◽  
Damping Model ◽  
Surface Vessel ◽  
Three Degrees Of Freedom

An analytical stability analysis of the steady trajectory for a surface vessel with various damping models is presented in this work. The analysis is based on a control-oriented, three degrees-of-freedom model that considers vessel motion only in the horizontal plane. The goal of this study is to understand the vessel trajectories predicted by this reduced order model for model-based control design. Straight line and circular motion stability conditions for each trajectory are derived and presented for the various damping models. The results of this analysis show that either a straight line or a circular steady trajectory is possible, depending on the magnitude of the surge force and the form of the damping model used to represent viscous drag, vortex shedding, and losses due to the surface wake generated by the vessel motion. However, the straight line motion is much less likely for the vessel considered in this work.

scholarly journals Computational Analysis of the Active Control of Incompressible Airfoil Flutter Vibration Using a Piezoelectric V-Stack Actuator

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 369-394
Author(s):  
Carmelo Rosario Vindigni ◽  
Calogero Orlando ◽  
Alberto Milazzo
Keyword(s):  
Piezoelectric Actuator ◽  
Pid Controller ◽  
Degrees Of Freedom ◽  
Computational Analysis ◽  
Vibration Suppression ◽  
Population Decline ◽  
External Disturbances ◽  
Fem Model ◽  
Speed Range ◽  
Three Degrees Of Freedom

The flutter phenomenon is a potentially destructive aeroelastic vibration studied for the design of aircraft structures as it limits the flight envelope of the aircraft. The aim of this work is to propose a heuristic design of a piezoelectric actuator-based controller for flutter vibration suppression in order to extend the allowable speed range of the structure. Based on the numerical model of a three degrees of freedom (3DOF) airfoil and taking into account the FEM model of a V-stack piezoelectric actuator, a filtered PID controller is tuned using the population decline swarm optimizer PDSO algorithm, and gain scheduling (GS) of the controller parameters is used to make the control adaptive in velocity. Numerical simulations are discussed to study the performance of the controller in the presence of external disturbances.

scholarly journals Active Disturbance Rejection for a Three Degrees of Freedom Gyroscope

2018 ◽  
Vol 51 (13) ◽  
pp. 372-377 ◽  
Author(s):  
Juan E. Andrade García ◽  
Alejandra Ferreira de Loza ◽  
Luis T. Aguilar ◽  
Ramón I. Verdés
Keyword(s):  
Disturbance Rejection ◽  
Degrees Of Freedom ◽  
Active Disturbance Rejection ◽  
Three Degrees Of Freedom

scholarly journals Control of an IPMC Soft Actuator Using Adaptive Full-Order Recursive Terminal Sliding Mode

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 33
Author(s):  
Romina Zarrabi Ekbatani ◽  
Ke Shao ◽  
Jasim Khawwaf ◽  
Hai Wang ◽  
Jinchuan Zheng ◽  
...  
Keyword(s):  
Sliding Mode ◽  
External Disturbance ◽  
Tracking Error ◽  
Working Environment ◽  
Parametric Uncertainties ◽  
Metal Composite ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Positioning Accuracy ◽  
Soft Actuator

The ionic polymer metal composite (IPMC) actuator is a kind of soft actuator that can work for underwater applications. However, IPMC actuator control suffers from high nonlinearity due to the existence of inherent creep and hysteresis phenomena. Furthermore, for underwater applications, they are highly exposed to parametric uncertainties and external disturbances due to the inherent characteristics and working environment. Those factors significantly affect the positioning accuracy and reliability of IPMC actuators. Hence, feedback control techniques are vital in the control of IPMC actuators for suppressing the system uncertainty and external disturbance. In this paper, for the first time an adaptive full-order recursive terminal sliding-mode (AFORTSM) controller is proposed for the IPMC actuator to enhance the positioning accuracy and robustness against parametric uncertainties and external disturbances. The proposed controller incorporates an adaptive algorithm with terminal sliding mode method to release the need for any prerequisite bound of the disturbance. In addition, stability analysis proves that it can guarantee the tracking error to converge to zero in finite time in the presence of uncertainty and disturbance. Experiments are carried out on the IPMC actuator to verify the practical effectiveness of the AFORTSM controller in comparison with a conventional nonsingular terminal sliding mode (NTSM) controller in terms of smaller tracking error and faster disturbance rejection.

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