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 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 Strategies of traversing obstacles and the simulation for a forestry chassis

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877390 ◽  
Author(s):  
Yue Zhu ◽  
Jiangming Kan ◽  
Wenbin Li ◽  
Feng Kang
Keyword(s):  
Multibody Dynamics ◽  
Inclination Angle ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Hydraulic Cylinder ◽  
Single Side ◽  
Simulation Results ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Small Inclination

As to the complicated terrain in forest, forestry chassis with an articulated body with three degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is a novel chassis that can surmount obstacles. In addition, the rear frame of FC-3DOF&LW is regarded as the platform to carry equipment. Small inclination angle for rear frame contributes to stability and ride comfort. This article describes the strategy of traversing obstacles and simulation for FC-3DOF&LW that drives in forest terrain. First, key structures of FC-3DOF&LW are briefly introduced, which include articulated structure with three degrees of freedom and luffing wheel-leg. Based on the sketch of luffing wheel-leg, the movement range of luffing wheel-leg is obtained by hydraulic cylinder operation. Second, the strategy of crossing obstacles that are simplified three models of terrain is presented, and the simulation for surmounting obstacles is constructed in multibody dynamics software. The simulation results demonstrate that the inclination angle of rear frame is 18° when slope is 30°. A maximum 12° decrease of inclination angle for rear frame can be acquired when luffing wheel-legs are applied. For traversing obstacles with both sides, the maximum inclination angle of rear frame is about 1.2° and is only 3° for traversing obstacles with single side.

Actuator Array Dynamics Incorporating Actuator Inertia

2013 ◽  
Author(s):  
Mark D. Bedillion
Keyword(s):  
Degrees Of Freedom ◽  
Friction Model ◽  
Object Motion ◽  
Prior Work ◽  
Control Laws ◽  
Distributed Manipulation ◽  
Actuator Arrays ◽  
Simulation Results ◽  
Two Degree Of Freedom ◽  
Three Degrees Of Freedom

Actuator arrays are planar distributed manipulation systems that use multiple two degree-of-freedom actuators to manipulate objects with three degrees of freedom (x, y, and θ). Prior work has discussed actuator array dynamics while neglecting the inertia of the actuators; this paper extends prior work to the case of non-negligible actuator inertia. The dynamics are presented using a standard friction model incorporating stiction. Simulation results are presented that show object motion under previously derived control laws.

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.

Design, kinematic and dynamic modeling of a novel tripod based manipulator

Robotica ◽  
2014 ◽  
Vol 34 (10) ◽  
pp. 2186-2204 ◽  
Author(s):  
Dan Zhang ◽  
Bin Wei
Keyword(s):  
Set Theory ◽  
Dynamic Modeling ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
General Function ◽  
Multi Objective Optimization ◽  
Gf Set ◽  
Hybrid Manipulator ◽  
New Type ◽  
Three Degrees Of Freedom

SUMMARYThis paper proposes a novel three-degrees-of-freedom (3-DOF) hybrid manipulator, 3PU*S-PU, which evolves from the general function (Gf) set theory. After discussing the advantages of this new type of hybrid manipulator, this report analyzes the kinematic and Jacobian matrix of the manipulator. Subsequently, the kinematic performances, including stiffness/compliance, and workspace, undergo analysis, followed by the multi-objective optimization of the compliance and workspace. The Lagrangian method provides the framework for briefly analyzing the dynamics of the proposed manipulator. Finally, the results of this assessment comprise a guideline for controlling the manipulator.

Operational Space Prescribed Tracking Performance and Compliance in Flexible Joint Robots

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Abdelrahem Atawnih ◽  
Zoe Doulgeri ◽  
George A. Rovithakis
Keyword(s):  
Degrees Of Freedom ◽  
Position Tracking ◽  
Admittance Control ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Operational Space ◽  
Control Scheme ◽  
Simulation Results ◽  
Flexible Joint Manipulator ◽  
Three Degrees Of Freedom

In this work, an admittance control scheme is proposed utilizing a highly robust prescribed performance position tracking controller for flexible joint robots which is designed at the operational space. The proposed control scheme achieves the desired impedance to the external contact force as well as superior position tracking in free motion without any robot model knowledge, as opposed to the torque based impedance controllers. Comparative simulation results on a three degrees-of-freedom (3DOF) flexible joint manipulator, illustrate the efficiency of the approach.

The Steering Performance Analysis of Multi-Axle Vehicle Based on Sideslip Angle Control Strategy

2014 ◽  
Vol 701-702 ◽  
pp. 799-802
Author(s):  
Ping Xia Zhang ◽  
Li Gao ◽  
Yong Qiang Zhu
Keyword(s):  
Control Strategy ◽  
Front Wheel ◽  
Convergence Time ◽  
Step Response ◽  
Steering Angle ◽  
Sideslip Angle ◽  
Yaw Rate ◽  
Test Variable ◽  
Adams Software ◽  
Controlling Variables

Because there are several axles in multi-axle vehicle, steering controlling is very complex. It is proposed to use the front wheel steering angle and D as input controlling variables, and to realize centroid sideslip angle control. A five-axle vehicle model was built with ADAMS software, and the control strategy was built with Simulink software. The steering angle step response simulations were processed, such as only font wheels steering, fixed D value steering, and different sideslip angle control strategy. It is found that for only font wheels steering test, variable sideslip angle control strategy could make the overshoot of yaw rate reduce from 98% to 10%, convergence time reduce to 57%.

The Kinematics Model and Simulation of a Subminiature Based on Marine Ranching

2014 ◽  
Vol 909 ◽  
pp. 135-140
Author(s):  
Jie Jiang Shao ◽  
Feng Peng Wei ◽  
Lan Zhen
Keyword(s):  
Degrees Of Freedom ◽  
Complex Environment ◽  
Kinematics Model ◽  
Model And Simulation ◽  
Simulation Results ◽  
Freedom Movement ◽  
Three Degrees Of Freedom

A subminiature submersible has been designed on the basis of the condition of the marine ranching, especially the shape of the submersible in view of the complex environment of marine ranching. Its mainly designed from three major movements, namely advance, ups-downs and yawing movement; it can complete three degrees of freedom movement. At the same time a force analysishas beengiven. Thetransfer functions have been deduced, and the simulation structure has been designed according to its kinematics model. According to the simulation results, the feasibility of the kinematics model was verified.

Design of Fuzzy Logic Controller for Four Wheel Steering System

2005 ◽  
Author(s):  
Evren Ozatay ◽  
Samim Y. Unlusoy ◽  
Murat A. Yildirim
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Control Strategies ◽  
Steering System ◽  
Front Wheel ◽  
Sideslip Angle ◽  
Yaw Rate ◽  
Nonlinear Vehicle Model ◽  
Three Degree Of Freedom ◽  
Vehicle Dynamics Control

Integration of the driver’s steering input together with the four-wheel steering system (4WS) in order to improve the vehicle’s dynamic behavior with respect to yaw rate and body sideslip angle is possible with intelligent vehicle dynamics control systems. The goal of this study is to develop a fuzzy logic controller for this purpose. In the first stage of the study, a three-degree of freedom nonlinear vehicle model including roll dynamics is developed. The Magic Formula is applied in order to formulate the nonlinear characteristics of the tires. In the design of the fuzzy logic controller, a two-dimensional rule table is created based on the error and on the change in the error of sideslip angle, which is to be minimized. Fuzzy logic controlled model is then compared with front wheel steering vehicle and the vehicles having different control strategies that have previously been studied in literature. Simulations indicate that fuzzy logic controlled vehicle can provide zero body sideslip angle in transient motion and quick response in terms of yaw rate during steady state cornering and lane change maneuvers.

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