Steering Linkage Research Articles

Study regarding the implementation of an Ackerman steering geometry in MATLAB

In dynamic vehicle behavior the steering system has an important role. The vehicle stability, maneuverability depends on steering system characteristics. Majority of passenger vehicles uses the rack pinion steering linkage system. In this article, a simplified planar six-bar linkage model of the rack pinion steering system is presented. Kinematic relations are used to determine every linkage position in every possible situation. This simplified system contains a rack, tie rods, steering arms, and wheels. The six-bar linkage model is introduced in MATLAB SIMULINK. In the function of the rack displacement, the wheel angels are determined. The dimensions of this planar model can be estimated due to the minimum error between the calculated wheel angels for the rack and pinion system and an Ackerman principle based system with similar dimensions. For optimizing a system and for verifying the method numerical calculation are used.

Simulation Technique of Kinematic Processes in the Vehicle Steering Linkage

The results of the investigation of the turning kinematics of the steerable wheels of the KrAZ-7634NE off-road vehicle with a wheel formula 8x8 and two front steer axles are given. The theoretical relations between the steer angles of the steerable wheels on the basis of the scheme of double-axle steering turning of the vehicle are shown. The mathematical model of flat four-bar vehicle steering linkage is developed, it determines the relation between the steering linkage left and right steering arms turning angles at any turning radius of the vehicle. KrAZ-7634HE steering three-dimensional model was created and simulation technique of its work was carried out using Creo software. It has been shown that the flat steering linkage model provides sufficient accuracy of calculations in analysis of turning kinematics. The design data can be used for any vehicles that have a similar steering linkage, they allow to analyze the impact of the vehicle design parameters on the turning kinematics and optimize them. Further study of the impact of the kingpin inclinations on the steering linkage kinematic and power characteristics are required.

Reliability analysis of motion mechanism under three types of hybrid uncertainties

Hybrid reliability analysis of motion mechanism, in which the inputs contain both random variables and interval variables, is investigated in this paper. Firstly, the hybrid uncertainty is divided into three categories. In the first category, the inputs that include both random variables and interval variables are considered. In the second category, the inputs that include random variables with interval distribution parameters are considered. In the third category, the inputs that include both random variables with interval distribution parameters, and interval variables are considered. The above three types of uncertainties outline the general situation of hybrid uncertainties. In order to achieve the reliability analysis of motion mechanism under the above three hybrid uncertainties, this paper presents a method of combining the Poisson's assumption-based first passage method and a double loop iterative algorithm. The specific calculation process is described in detail by a numerical example. Simultaneously, the accuracy and efficiency of the proposed is also shown and discussed by comparing the Monte Carlo simulation (MCS) results in this numerical example. Finally, the proposed method is applied to two practical engineering examples, a crank slider mechanism and a rack-and-pinion steering linkage.

Simplified planar model of a car steering system with rack and pinion and McPherson suspension

The paper presents the analysis and optimization of steering system with rack and pinion and McPherson suspension using spatial model and equivalent simplified planar model. The dimension of the steering linkage that give minimum steering error can be estimated using planar model. The steering error is defined as the difference between the actual angle made by the outer front wheel during steering manoeuvers and the calculated angle for the same wheel based on the Ackerman principle. For a given linear rack displacement, a specified steering arms angular displacements are determined while simultaneously ensuring best transmission angle characteristics (i) without and (ii) with imposing linear correlation between input and output. Numerical examples are used to illustrate the proposed method.

Multiobjective optimization of a steering linkage

In this paper, multi-objective optimization of a rack-and-pinion steering linkage is proposed. This steering linkage is a common mechanism used in small cars with three advantages as it is simple to construct, economical to manufacture, and compact and easy to operate. In the previous works, many researchers tried to minimize a steering error but minimization of a turning radius is somewhat ignored. As a result, a multi-objective optimization problem is assigned to simultaneously minimize a steering error and a turning radius. The design variables are linkage dimensions. The design problem is solved by the hybrid of multi-objective population-based incremental learning and differential evolution with various constraint handling schemes. The new design strategy leads to effective design of rack-and-pinion steering linkages satisfying both steering error and turning radius criteria.

Multi-objective Optimization of the Steering Linkages Considering Transmitting Ratios

Trapezoidal mechanisms and swing arm mechanisms in the steering linkages were usually designed separately, and only the steered wheel deflection errors were fixed as the optimization objective. To deal with these design faults, multi-objective optimization model of the steering linkages were developed in this paper. The model considered not only the steered wheel deflection errors but also the unevenness of the steering linkages transmitting ratios. In the model, the optimization variables were the link dimensions of the steering linkages and the optimization was processed in Adams software using SPQ algorithm. The optimization results show that the unevenness of the first axle steering mechanism transmitting ratio reduced from 9.7%

Global reliability sensitivity analysis of motion mechanisms

The kinematic failure of a mechanism is commonly caused by the random input errors such as the errors of component dimensions and motion inputs. For identifying the main source of the failure probability, the global reliability sensitivity analysis is introduced. The method is based on decomposing the variance of the failure domain indicator function into partial variances of increasing orders, which enable attributing the failure probability to each of the random input errors and their interactions. Then the analytical solutions of the global reliability sensitivity indices are derived based on the first-order Taylor series expansion of the motion error function. Compared with the traditional local reliability sensitivity indices, the global reliability sensitivity analysis technique has two main merits. First, it is more suitable for ranking the importance of random input errors and identifying the source of failure probability. Second, it provides not only the individual effect of each random input error on the failure probability but also their interaction and total effects. The engineering significance of the global reliability sensitivity indices as well as the effectiveness of the analytical method for computing the global reliability sensitivity indices are demonstrated with a four-bar sine function generator mechanism and a rack-and-pinion steering linkage.

Time-dependent reliability sensitivity analysis of motion mechanisms

Reliability sensitivity analysis aims at identifying the source of structure/mechanism failure, and quantifying the effects of each random source or their distribution parameters on failure probability or reliability. In this paper, the time-dependent parametric reliability sensitivity (PRS) analysis as well as the global reliability sensitivity (GRS) analysis is introduced for the motion mechanisms. The PRS indices are defined as the partial derivatives of the time-dependent reliability w.r.t. the distribution parameters of each random input variable, and they quantify the effect of the small change of each distribution parameter on the time-dependent reliability. The GRS indices are defined for quantifying the individual, interaction and total contributions of the uncertainty in each random input variable to the time-dependent reliability. The envelope function method combined with the first order approximation of the motion error function is introduced for efficiently estimating the time-dependent PRS and GRS indices. Both the time-dependent PRS and GRS analysis techniques can be especially useful for reliability-based design. This significance of the proposed methods as well as the effectiveness of the envelope function method for estimating the time-dependent PRS and GRS indices are demonstrated with a four-bar mechanism and a car rack-and-pinion steering linkage.

Design Approach for the Vehicle's Steering Linkage Fitted on Rigid Axle

The steering system of a vehicle consists of two subsystems: the steering linkage, which correlates the steering angles of all the steerable road-wheels, and the actuation subsystem, which connects the driver's steering-wheel with one mobile element of the steering linkage. In the case of the vehicles with rigid steering axles, the most used steering linkage is a simple mechanism, composed of four bars (one being the base) connected with four joints. However, the design of the steering linkage isn't an easy task, mainly because the wanted correlation function is difficult to specify and because the packaging restrictions are very important. The present paper shows a possible approach to define the optimization function and the dimensions of the correlation steering mechanism.

Coordinate calculation method of steering linkage

A new calculation method for steering linkage based on the equation of a circle is proposed. The method can be used with iterative method of dynamic calculation for steering system of wheel tractors.

Variable structure controller design for steer-by-wire system of a passenger car

The electric power steering (EPS) system was developed and the steer-by-wire (SBW) system achieves the purposes of EPS. The advantages of SBW are packaging flexibility, advanced vehicle control system, and superior performance. No mechanical linkage exists between the steering gear and steering column in the SBW system. The steering wheel and front-wheel steering can be controlled independently. The SBW system consists of two motors controlled by an electronic control unit (ECU). One motor is in the steering wheel and develops the steering feel of the driver and the other motor is in the steering linkage and improves vehicle maneuverability and stability. Moreover, the active front steering (AFS) system can be added to the SBW system. AFS reduces the difference between actual and estimated vehicle yaw rate. Up-to-date information from the steering wheel enables drivers to identify road conditions through the tire force, which should be fed back to the steering wheel. Furthermore, several control algorithms related to the vehicle and motor can be used together through the self-aligning torque, which is fed back to the steering wheel. This study proposes a method to control the vehicle yaw rate through an SBW system. This control method is based on a PID control method for the steering-wheel-motor controller, as well as on a sliding mode control (SMC) method for the front-wheel-motor controller and yaw stability controller. The SBW system is modeled using a bond graph method. Results imply that the controllers are robust enough when in contact with nonlinear properties of tire and road conditions. This study is expected to guide further research on the SBW system.

Steering System Kinematic and Steady-State Cornering Analyses of the ITS Electric Car

Steering linkages play an important role in maneuvering of cars. In order to provide pure rolling of the road wheels and to reduce wear of the tires, the steering linkage must be able to turn the wheels such that their axis intersection point lies on the rear wheel axis. This condition is known as the Ackermann condition. However, in reality, Ackermann condition is difficult to satisfy for every cornering radius. The only effort we can do is to synthesize the linkage so that the Ackermann condition is satisfied for any turning radius as closely as possible. Hence, an appropriate kinematic model of the steering linkage is essential. The purpose of this research is to analyze the rack and pinion steering linkage for the ITS electric car prototype. From this analysis, the information on the steering linkage dimension and the placement of the steering linkage that give minimum steering error can be obtained. The steering error is defined as the difference between the actual angle made by the outer front wheel during steering maneuvers and the correct angle for the same wheel based on the Ackerman principle. In addition, the steady-state cornering behavior analysis is also conducted. From this analysis, the information of the center of gravity location that give better cornering characteristics can be obtained. Therefore, these analyses help and can be used as starting point to design the chassis and cabin for the ITS electric car prototype.

Optimum design of a rack-and-pinion steering linkage matching a rectilinear suspension system

This paper proposes a spatial kinematic model of rack-and-pinion steering linkage matching a rectilinear suspension system. Minimising the steering error and avoiding the interference between the steering linkage and suspension system are used to optimise the steering linkage based on the requirements of transmission efficiency and understeering criterion. Numerical calculation and result comparison show the advanced performance of the steering linkage and verify the optimisation method. This work lays a foundation for the design of steering system and rectilinear suspension system.

Optimization of Multi-axle Steering Linkage with Active Rear Axles Steering

Optimization of Multi-axle Steering Linkage with Active Rear Axles Steering

Influences of system parameters on dynamic behavior of the vehicle shimmy system with clearance in steering linkage

Influences of system parameters on dynamic behavior of the vehicle shimmy system with consideration of clearance in the steering linkage mechanism are analyzed. The kinematic pair of steering linkage mechanism with clearance between the steering tie rod and left trapezoidal arm is modeled based on Hertz’s law, and a four-degree-of-freedom dynamic model of a vehicle shimmy system with consideration of clearance in the steering linkage mechanism is presented. Based on this model, numerical analysis is carried out, and the influences of the parameters, such as clearance, contact surface stiffness of the kinematic pair, wheel alignment parameters, and vehicle speed on the dynamic response of the vehicle shimmy system are discussed. It is shown that, considering the clearance in the steering linkage mechanism, these parameters can make a coupled contribution to the dynamic response of the vehicle shimmy system, and some effective measurements for vehicle shimmy attenuation are available. The conclusions will provide theoretical basis for effective vehicle shimmy control, especially for vehicles which are in use.

Optimal synthesis of function generation in steering linkages

This paper presents an approach to optimize planar mechanisms for function generation synthesis. It is applied to the design of different steering linkages used in road vehicles where the Ackermann condition is formulated as the objective function. Four different mechanisms are kinematically defined and synthesized in terms of the proposed method. Limitations of the size of the elements are also considered by means of inequality constraints. Solutions are presented as the difference between desired behaviour, established by Ackermann, and actual generated performance. The results show that the accuracy achieved by the proposed procedure is satisfactory for working conditions in this type of linkages.

The Design and Research of Steering Linkage Automatic Process Based on PLC

Aiming at the status of steering linkage with more work station requirements but low working, a set of steering linkage processing autoproductline system based on PLC is developed. The system has the advantages of high reliability, strong anti-interference ability, easy to use and simple program. It achieves all the automatic production of charging, radial facing, chamfering, reaming, tapping, grooving and blanking, decreases the work intensity of worker and improves production efficiency and qualified rate of product greatly.

Analysis and Optimization of the Double-Axle Steering Mechanism with Dynamic Loads

A hierarchical optimization procedure for the optimal synthesis of a double-axle steering mechanism used in truck with dynamic loads is presented. A multibody model of double-axle steering mechanism is presented to characterize the leaf spring effect. The influences of dynamic loads, the motion interference of steering linkage resulted from the elastic deformation of leaf spring, and the effects of wheel slip angles and the position discrepancies of wheel speed rotation centers are studied systematically. A hierarchical optimization method based on target cascading methodology is proposed to classify the design variables of double-axle steering mechanism into four levels. A double-axle steering mechanism for a heavy-duty truck is utilized to demonstrate the validity of the proposed method. The simulation results indicate that the hierarchical optimization procedure is effective and robust. And as a result, it will surely be widely used in engineering.

Dynamic Performance of Electro-hydraulic Steering System for Off-road Vehicles

The dynamic characteristics of an Electro-hydraulic (EH) steering system plays an important role in realizing an accurate steering control for an automatically guided vehicles. In this paper, a mathematical model has been developed for EH steering system that includes EH servo valve with mechanical feedback, steering actuation cylinders and associated steering linkages. A proportional-integral controller has been designed to improve the dynamic performance of EH steering system for off-road vehicles. The simulated system models using SIMULINK were validated using experimental tests. The control of steering angle using the proposed proportional-integral controller has been demonstrated for different soil conditions.

Robust Optimization Design on Vehicle Divided Steering Linkage

In view of the great fluctuation on objective functions which cause constraints dissatisfied, robust design is applied to the vehicle divided steering linkage optimization problem. A robust model is established by considering the kinematic pair clearance and structural error both in the objective functions and constrains. Optimum results show that,the design method can effectively guarantee the kinematics precision of steering mechanism and the transmission stability.