scholarly journals Design and Verification of Heading and Velocity Coupled Nonlinear Controller for Unmanned Surface Vehicle

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3427 ◽  
Author(s):  
Jiucai Jin ◽  
Jie Zhang ◽  
Deqing Liu
Keyword(s):  
Degrees Of Freedom ◽  
Lyapunov Theory ◽  
Velocity Control ◽  
Nonlinear Controller ◽  
Experiment Data ◽  
Unmanned Surface Vehicle ◽  
Autonomous Operation ◽  
The Stability ◽  
Velocity Tracking ◽  
Three Degrees Of Freedom

Unmanned Surface Vehicle (USV) is a novel multifunctional platform for ocean observation, and its heading and velocity control are essential and important for autonomous operation. A coupled heading and velocity controller is designed using backstepping technology for an USV called ‘USBV’ (Unmanned Surface Bathymetry Vehicle). The USBV is an underactuated catamaran, where the heading and velocity are controlled together by two thrusters at the stern. The three degrees-of-freedom equations are used for USBV’s modeling, which is identified using experiment data. The identified model, with two inputs, induces heading and velocity tracking, which are coupled. Based on the model, a nonlinear controller for heading and velocity are acquired using backstepping technology. The stability of the controller is proved by Lyapunov theory under some assumptions. The verification is presented by lake and sea experiments.

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 Modeling and Identification for Vector Propulsion of an Unmanned Surface Vehicle: Three Degrees of Freedom Model and Response Model

Sensors ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 1889 ◽  
Author(s):  
Dongdong Mu ◽  
Guofeng Wang ◽  
Yunsheng Fan ◽  
Xiaojie Sun ◽  
Bingbing Qiu
Keyword(s):  
Degrees Of Freedom ◽  
Response Model ◽  
Unmanned Surface Vehicle ◽  
Three Degrees Of Freedom

scholarly journals 3DOF Adaptive Line-Of-Sight Based Proportional Guidance Law for Path Following of AUV in the Presence of Ocean Currents

2019 ◽  
Vol 9 (17) ◽  
pp. 3518 ◽  
Author(s):  
Fengxu Liu ◽  
Yue Shen ◽  
Bo He ◽  
Junhe Wan ◽  
Dianrui Wang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Path Following ◽  
Lyapunov Theory ◽  
Line Of Sight ◽  
Average Error ◽  
Drift Angle ◽  
Reference Path ◽  
Guidance Law ◽  
Look Ahead ◽  
Three Degrees Of Freedom

In order to achieve high-precision path following of autonomous underwater vehicle (AUV) in the horizontal plane, a three degrees-of-freedom adaptive line-of-sight based proportional (3DOFAPLOS) guidance law is proposed. Firstly, the path point coordinate system is introduced, which is suitable for the conversion of an arbitrary path. Then, the appropriate look-ahead distance is obtained by an improved adaptive line-of-sight (ALOS) according to three degrees-of-freedom (3DOF), including the cross-track error, the curvature of reference path, and the forward speed. Moreover, combining three degrees-of-freedom ALOS (3DOFALOS) with proportional guidance law, the desired heading is calculated considering the drift angle. 3DOFAPLOS has two functions: in the convergence stage, 3DOFALOS plays a leading role, making AUV converge to the path more quickly and smoothly. In the guidance stage, proportional guidance law plays a major role in effectively resisting the influence of drift angle and making AUV sail along the reference path. If the path is curved, 3DOFALOS makes contributions in both stages, adjusting look-ahead distance in real time with respect to curvature. The stability of the designed closed system is proved by Lyapunov theory. Both simulation and experiment results have verified that 3DOFAPLOS has a satisfactory result, which improves tracking performance more than 50% compared with the traditional line-of-sight (LOS). Specifically, the mean average error (MAE) of path following under 3DOFAPLOS can be reduced by about 60%, and the root mean square error (RMSE) can be reduced by about 50% compared with LOS.

Analysis of Vehicle Dynamic Equilibrium Points with 3-DOF Based on Genetic Algorithm

2014 ◽  
Vol 608-609 ◽  
pp. 721-725
Author(s):  
Rong Li ◽  
Wei Min Li
Keyword(s):  
Genetic Algorithm ◽  
Vehicle Dynamics ◽  
Optimization Design ◽  
Degrees Of Freedom ◽  
Dynamic Equilibrium ◽  
Equilibrium Points ◽  
Vehicle Handling ◽  
Dynamic Modification ◽  
The Stability ◽  
Three Degrees Of Freedom

To further study the stability of vehicle dynamics, a vehicle handling stability’s nonlinear model (including longitudinal, lateral and yaw movement three degrees of freedom) was established. Genetic algorithm was proposed for the vehicle dynamics system’s equilibrium points with 3-DOF. This algorithm solves the problem that cannot be solved through the traditional analytic algorithms and numerical methods. Comparing with the existing research results, the feasibility of solving the equilibrium point by the genetic algorithm is verified. It provides the theoretical foundation for dynamic modification and optimization design of powertrain.

scholarly journals Nonanthropomorphic exoskeleton with legs based on eight-bar linkages

2018 ◽  
Vol 15 (1) ◽  
pp. 172988141875577 ◽  
Author(s):  
Jorge Curiel Godoy ◽  
Ignacio Juárez Campos ◽  
Lucia Márquez Pérez ◽  
Leonardo Romero Muñoz
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Main Function ◽  
Polynomial Functions ◽  
Forward And Inverse Kinematics ◽  
And Performance ◽  
The Stability ◽  
Robotic Leg ◽  
Three Degrees Of Freedom ◽  
Difficulty Walking

This article presents the principles upon which a new nonanthropomorphic biped exoskeleton was designed, whose legs are based on an eight-bar mechanism. The main function of the exoskeleton is to assist people who have difficulty walking. Every leg is based on the planar Peaucellier–Lipkin mechanism, which is a one degree of freedom linkage. To be used as a robotic leg, the Peaucellier–Lipkin mechanism was modified by including two more degrees of freedom, as well as by the addition of a mechanical system based on toothed pulleys and timing belts that provides balance and stability to the user. The use of the Peaucellier–Lipkin mechanism, its transformation from one to three degrees of freedom, and the incorporation of the stability system are the main innovations and contributions of this novel nonanthropomorphic exoskeleton. Its mobility and performance are also presented herein, through forward and inverse kinematics, together with its application in carrying out the translation movement of the robotic foot along paths with the imposition of motion laws based on polynomial functions of time.

Nonlinear Cutterhead Pose Control of Large-Diameter Slurry Shields in Complicated Stratum

2021 ◽  
Author(s):  
Hangjun Zhang ◽  
Jianhua Wei ◽  
Jinhui Fang ◽  
Yuzhu Yang
Keyword(s):  
Sliding Mode ◽  
Large Diameter ◽  
Adaptive Robust Control ◽  
Lyapunov Theory ◽  
Load Force ◽  
Nonlinear Controller ◽  
Special Adaptation ◽  
Pose Control ◽  
The Stability ◽  
Adaptation Law

Abstract To replace cutterhead worn tools conveniently or get rid of shield’s jamming effectively in complicated stratum, a new nonlinear cutterhead pose control system of large-diameter slurry shields is especially designed. High precision cutterhead pose control of large-diameter slurry shields is hardly achieved due to the uncertain load force and mass. A nonlinear controller constructed by adaptive robust control based on sliding mode is designed for this parallel mechanism, which includes a special adaptation law to compensate for the uncertainties. The stability of the whole closed loop system is verified based on Lyapunov theory. And the validity of the proposed strategy is proved by Simulink and AMESim co-simulation. The simulation results show that not only in control accuracy but also in parameter uncertainty, the designed nonlinear cutterhead pose control is effective.

Nonlinear Feedback Law for Tracking Control of DC-Actuated Robots

1999 ◽  
Author(s):  
L. Beji ◽  
M. Pascal
Keyword(s):  
Singular Perturbations ◽  
Tracking Control ◽  
Degrees Of Freedom ◽  
Control Law ◽  
Nonlinear Feedback ◽  
Serial Robot ◽  
The Stability ◽  
Stability Results ◽  
Three Degrees Of Freedom

Abstract In this paper, a nonlinear feedback law for tracking control of robots is proposed. The dynamic of actuators and only position measurements are taking into account to design the control law. The stability results are obtained from the passivity property of the system, and using singular perturbations techniques. Simulation tests are performed on a three degrees-of-freedom serial robot to illustrate our control law.

scholarly journals Modeling and Stability Analysis for the Vibrating Motion of Three Degrees-of-Freedom Dynamical System Near Resonance

2021 ◽  
Vol 11 (24) ◽  
pp. 11943
Author(s):  
Wael S. Amer ◽  
Tarek S. Amer ◽  
Seham S. Hassan
Keyword(s):  
Dynamical System ◽  
Degrees Of Freedom ◽  
Multiple Scales ◽  
Positive Influence ◽  
Theoretical Physics ◽  
Physical Parameters ◽  
The Third ◽  
Near Resonance ◽  
The Stability ◽  
Three Degrees Of Freedom

The focus of this article is on the investigation of a dynamical system consisting of a linear damped transverse tuned-absorber connected with a non-linear damped-spring-pendulum, in which its hanged point moves in an elliptic path. The regulating system of motion is derived using Lagrange’s equations, which is then solved analytically up to the third approximation employing the approach of multiple scales (AMS). The emerging cases of resonance are categorized according to the solvability requirements wherein the modulation equations (ME) have been found. The stability areas and the instability ones are examined utilizing the Routh–Hurwitz criteria (RHC) and analyzed in line with the solutions at the steady state. The obtained results, resonance responses, and stability regions are addressed and graphically depicted to explore the positive influence of the various inputs of the physical parameters on the rheological behavior of the inspected system. The significance of the present work stems from its numerous applications in theoretical physics and engineering.

scholarly journals Robust Control Design of Active Front-Wheel Steering on Low-Adhesion Road Surfaces

2021 ◽  
Vol 12 (3) ◽  
pp. 153
Author(s):  
Chuanwei Zhang ◽  
Bo Chang ◽  
Jianlong Wang ◽  
Shuaitian Li ◽  
Rongbo Zhang ◽  
...  
Keyword(s):  
Robust Control ◽  
Control Strategy ◽  
Degrees Of Freedom ◽  
Reference Model ◽  
Front Wheel ◽  
Good Path ◽  
Road Surfaces ◽  
Robust Control Design ◽  
The Stability ◽  
Three Degrees Of Freedom

In order to improve the stability of vehicle steering on low-adhesion road surfaces, this paper designed a hybrid robust control strategy, H2/H∞, for active front-wheel steering (AFS) based on robust control theory. Firstly, we analyzed the influence of the sidewall stiffness and road adhesion coefficient of the tires on vehicle stability, through which we can study the wheel deflection characteristics of low-adhesion roads. Secondly, the reference yaw velocity of the vehicle was calculated using the three-degrees-of-freedom model as the reference model, through which, taking the norm H∞ as the objective function and the norm H2 as the limit to control the output, the hybrid robust control strategy H2/H∞ of the AFS system on a low-adhesion road surface was developed. Finally, the simulation experiment was carried out by the Simulink/CarSim co-simulation platform and a hardware-in-the-loop (HIL) experiment. In this paper, the results show that the AFS control strategy can improve the vehicle handling stability on low-adhesion road surfaces, and the controller has good path tracking performance and robustness.

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