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.

scholarly journals Hierarchical Control of Nonlinear Active Four-Wheel-Steering Vehicles

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2930 ◽  
Author(s):  
Jie Tian ◽  
Jie Ding ◽  
Yongpeng Tai ◽  
Ning Chen
Keyword(s):  
Degrees Of Freedom ◽  
Reference Model ◽  
Hierarchical Control ◽  
Front Wheel ◽  
Sideslip Angle ◽  
Yaw Rate ◽  
Rate Feedback ◽  
New Type ◽  
Simulation Results ◽  
Three Degrees Of Freedom

A new type of hierarchical control is proposed for a four-wheel-steering (4WS) vehicle, in which both the sideslip angle and yaw rate feedback are used, and the saturation of the control variables (i.e., the front and rear steering angles) is considered. The nonlinear three degrees of freedom (3DOF) 4WS vehicle model is employed to describe the uncertainties originating from the operating situations. Further, a normal front-wheel-steering (2WS) vehicle with a drop filter of the sideslip angle is selected as the reference model. The inputs for the rear and front steering angles of the linear 2DOF 4WS, required to achieve the performances described by the reference model, are obtained and controlled by the upper controller. Further, the lower controller is designed to eliminate the state error between the linear 2DOF and nonlinear 3DOF 4WS vehicle models. The simulation results of several vehicle models with/without the controller are presented, and the robustness of the hierarchical control system is analyzed. The simulation results indicate that using the proposed hierarchical controller yields the same performance between the nonlinear 4WS vehicle and the reference model, in addition to exhibiting good robustness.

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.

Research on the Cornering Characteristics of Three-Axle Vehicle

2014 ◽  
Vol 945-949 ◽  
pp. 567-570
Author(s):  
Bo Xu ◽  
Sheng Min Cui ◽  
Xiang Yu Wu
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Front Wheel ◽  
Heavy Vehicle ◽  
Sideslip Angle ◽  
Motion Equations ◽  
Dynamic Steering ◽  
Angular Scale ◽  
Control Target ◽  
The Stability

A multi-axle dynamic steering technology was proposed to solve the steering stability and maneuverability problem of heavy vehicle. Two degrees of freedom linear steering-model and motion-equations of three-axle vehicle was established. Taking the zero sideslip angle as the control target and the proportional rear-front wheel angle as control method, we got the angular scale-factor equation and related matrix of the state space and transfer function. The MATLAB software was used to simulate the different steering modes stability steady-state and transient response. The results show that by using proportional control method the sideslip angle can be stabilized near zero and by using multi-axle dynamic steering technology the stability and maneuverability of the vehicle when steering can be improved effectively.

Vehicle Dynamics Model Establishing and Dynamic Characteristic Simulation

2013 ◽  
Vol 404 ◽  
pp. 244-249
Author(s):  
Rui Wang ◽  
Hao Zhang ◽  
Xian Sheng Li ◽  
Xue Lian Zheng ◽  
Yuan Yuan Ren
Keyword(s):  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Rear Wheel ◽  
Front Wheel ◽  
Step Response ◽  
Steering Wheel ◽  
Vehicle Simulation ◽  
Equivalent Mechanical Model ◽  
External Forces ◽  
Three Degrees Of Freedom

By establishing bus simplify coordinate system model and equivalent mechanical model, inertial forces and external forces are analyzed through vehicle lateral movement and vehicle's yaw motion and roll motion. Three degrees of freedom linear motion equation of vehicle is established taking into account lateral motion, yawing movement and rolling motion of vehicle and it can be solved by using method of state space equation. Vehicle dynamic characteristics are analyzed by using this method and programming with Matlab. Vehicle in steering wheel angle step response is analyzed under the conditions of different tire wheel cornering stiffness, moment of inertia, height of center of mass. The results show that increasing rear wheel cornering stiffness, reducing front wheel cornering stiffness and center of mass height, which can effectively improve stability of vehicle. Simulation results provide a theoretical basis and reference for the selection and design of vehicle.

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.

Study on Scanner for Large-Diameter Tubular Joint Welds Based on Ultrasonic Phased Array

2006 ◽  
Vol 532-533 ◽  
pp. 265-268
Author(s):  
Zong Quan Deng ◽  
Guang Ping Hao ◽  
De Wei Tang ◽  
Bao Hua Shan
Keyword(s):  
Control Strategy ◽  
Degrees Of Freedom ◽  
Phased Array ◽  
Large Diameter ◽  
Ultrasonic Inspection ◽  
The Other ◽  
Tubular Joints ◽  
Ultrasonic Phased Array ◽  
Tubular Joint ◽  
Three Degrees Of Freedom

For the complexity of weld, the automatic inspecting for the tubular joints which are in working is difficult. Therefore the scanner which has three degrees of freedom for inspecting of large-diameter tubular joints was studied and manufactured based on the scanning principle of ultrasonic phased array. The following of probe to weld is realized by the simultaneous motion of two degrees of freedom and the pose between probe and weld is adjusted by the other degree of freedom. The control strategy of the scanner was provided. Experiments were made with scanner on reference blocks, the results indicate that the automatic ultrasonic phased array inspection is more excellent than the conventional ultrasonic inspection in reliability and repetition.

Model-based robust control design and experimental validation of SCARA robot system with uncertainty

2022 ◽  
pp. 107754632110421
Author(s):  
ShengChao Zhen ◽  
MuCun Ma ◽  
XiaoLi Liu ◽  
Feng Chen ◽  
Han Zhao ◽  
...  
Keyword(s):  
Robust Control ◽  
Control Algorithm ◽  
Lyapunov Method ◽  
Control Method ◽  
External Disturbance ◽  
Scara Robot ◽  
Model Based ◽  
Robust Control Design ◽  
Robot Performance ◽  
The Stability

In this paper, we design a novel robust control method to reduce the trajectory tracking errors of the SCARA robot with uncertainties including parameters such as uncertainty of the mechanical system and external disturbance, which are time-varying and nonlinear. Then, we propose a deterministic form of the model-based robust control algorithm to deal with the uncertainties. The proposed control algorithm is composed of two parts according to the assumed upper limit of the system uncertainties: one is the traditional proportional-derivative control, and the other is the robust control based on the Lyapunov method, which has the characteristics of model-based and error-based. The stability of the proposed control algorithm is proved by the Lyapunov method theoretically, which shows the system can maintain uniformly bounded and uniformly ultimately bounded. The experimental platform includes the rapid controller prototyping cSPACE, which is designed to reduce programming time and to improve the efficiency of the practical operation. Moreover, we adopt different friction models to investigate the effect of friction on robot performance in robot joints. Finally, numerical simulation and experimental results indicate that the control algorithm proposed in this paper has desired control performance on the SCARA robot.

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.

Multibody Analysis and Design of a Reconfigurable Parallel Kinematics Manipulator

2015 ◽  
Author(s):  
Matteo Palpacelli ◽  
Massimo Callegari ◽  
Luca Carbonari ◽  
Giacomo Palmieri
Keyword(s):  
Control Strategy ◽  
Degrees Of Freedom ◽  
Parallel Kinematics ◽  
Analysis And Design ◽  
Pure Rotation ◽  
Analytic Expressions ◽  
Robot Leg ◽  
Moving Platform ◽  
Actuation Systems ◽  
Three Degrees Of Freedom

This paper presents the design of a reconfigurable parallel kinematics machine endowed with three degrees of freedom of pure translation, or alternately of pure rotation. Such reconfigurability results from the use of lockable spherical joints, which realize the connection between each robot leg and the moving platform. Three actuated legs are used to drive the platform motion. The change of configuration occurs only at a specific pose, called home configuration. A control strategy allows to manage the shift phase and activate the two mobilities one at a time. Multibody simulations allowed to analyze the dynamic behavior of the manipulator and to verify the choices made with regard to the robot mechanics and the size of actuation systems. Position and differential kinematics of the manipulator are briefly introduced in order to demonstrate the simplicity of the analytic expressions and the mechanical feasibility of the manipulator.

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.

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