Steering Trapezoid Research Articles

СОГЛАСОВАНИЕ ГЕОМЕТРИЧЕСКИХ ХАРАКТЕРИСТИК ФАКТИЧЕСКОГО ПОВОРОТА КОЛЁСНОЙ МАШИНЫ

Based on the above calculation scheme of controlled curvilinear motion of a wheeled vehicle, it was revealed that the steering trapezoid causes some discrepancy between the kinematics of real and correct rotation. It is established that when adjusting the track width of the machine, the kinematic mismatch between the optimal rolling conditions of the wheels increases, and, consequently, the calculated dependences of the parameters of the ideal turn will not give a satisfactory result when analyzing the actual turn. The minimum theoretical turning radius is taken as an estimated indicator of the turnability of a wheeled vehicle. The conclusion of a multifunctional analytical dependence for determining the theoretical minimum turning radius of a wheeled vehicle, the wheels of which are controlled by a steering trapezoid, is presented. The resulting formula includes the longitudinal base of the machine, the pin track, the angles of rotation of the inner and outer steerable wheels. A comparison of the calculation results according to the developed and known formulas is given, which confirmed the complete convergence. It was found that, for example, an increase in the pivot track of the machine by 0.2 m leads to an increase in the theoretical minimum radius of the actual turn by 16.5%, and the distance from the continuation of the rear axle to the instantaneous center of rotation by 45.07...98.02% when the angle of rotation of the inner steering wheel changes from 20° to 40°.

Optimum Design of a Tractor Steering Trapezoid Based on a Hybrid Genetic Algorithm

Optimum Design of a Tractor Steering Trapezoid Based on a Hybrid Genetic Algorithm

High-gain observer-based pump/valve combined control for heavy vehicle electro-hydraulic servo steering system

Electro-hydraulic servo steering system (EHSSS) has been widely used in multi-axle heavy vehicles. Noteworthy, the traditional EHSSS controlled only by servo solenoid valve has amounts of energy loss in throttling orifice. Although the steering control accuracy is ensured, it leads to low energy efficiency. In this paper, a novel pump/valve combined control (PVCC) EHSSS is proposed to increase the energy efficiency, which only uses one servo motor pump and one servo solenoid valve to drive the steering trapezoid mechanism. Based on the control objectives of low pressure difference in valve orifice and high steering tracking performance, a dual-input-dual-output control strategy is proposed. To guarantee the high steering tracking performance of PVCC steering system, a high-gain observer based sliding mode controller (HGO-SMC) is designed for controlling the spool displacement of servo solenoid valve. During the steering process, the servo motor pump is controlled by a simple speed feedforward and PID controller, so that the pressure difference in throttling orifice is kept at a low value to reduce the energy wasted. The experimental comparison results show that the proposed method can achieve the same tracking performance as valve control EHSSS with less energy consumption.

PARAMETER OPTIMIZATION OF TRACTOR'S STEERING TRAPEZOID MECHANISM BASED ON IMPROVED ADAPTIVE DIRECTION STRATEGY TEACHING-LEARNING-BASED OPTIMIZATION

The parameter optimization of the tractor's steering trapezoid mechanism is a traditional optimization problem, and the teaching-learning-based optimization (TLBO) has a better solving ability for parameter optimization of the tractor's steering trapezoid. However, the teacher stage and student stage of TLBO limit the accuracy and stability and the ability to jump out of the local optimization solution. To obtain an optimal solution with an higher accuracy, an improved adaptive direction strategy teaching-learning-based optimization (IADS-TLBO) was used. This improved the feedback stage based on the adaptive direction strategy teaching-learning-based optimization (ADS-TLBO). The IADS-TLBO was verified by three different testing functions, and the results showed that the improved ideas are valid and feasible. Finally, the IADS-TLBO was used to optimize the steering trapezoid mechanism of JOHN DEERE T600. The optimal parameters obtained were as follows: the bottom angle was 35.4º, and the steering arm length was 154 mm. A verification experiment was conducted in the farm tool laboratory of Northeast Agricultural University (China). The experimental results showed that the average bottom angle was 35.48º, and the relative error between the measured and optimized bottom angles was 0.23%, which is less than 5%. This result showed that the results obtained by IADS-TLBO were reliable.

Mechanisms of power distribution: principles of kinematic and force analysis

The article considers the features of performing kinematic and power analysis of a controlled power mechanism for the transmission of wheeled transport and transport-technological machines. Such mechanisms are currently used mainly on cars in order to improve handling, stability, traction and dynamic properties in severe road conditions. Such mechanisms are not produced in Russia, but theoretical studies are currently being conducted, the results of which will allow determining the main parameters of the mechanism and synthesizing its kinematic scheme. The proposed approaches are based on the methods used in the kinematic and force analysis of planetary gears, but it is taken into account that the mechanism of power distribution during operation has two degrees of freedom. It is indicated that there is a structural and functional similarity between the power distribution mechanism of the car and the turning mechanism of the tracked vehicle. A method is proposed for calculating the gear ratio of the power distribution mechanism according to the condition of matching the minimum possible turning radius provided by the steering trapezoid kinematics and the calculated turning radius.

Establishment and tracking control of trapezoidal steering wheel angle model for autonomous vehicles

Human drivers have rich and diverse driving characteristics on curved roads. Finding the characteristic quantities of the experienced drivers during curve driving and applying them to the steering control of autonomous vehicles is the research goal of this article. We first recruited 10 taxi drivers, 5 bus drivers, and 5 driving instructors as the representatives of experienced drivers and conducted a real car field experiment on six curves with different lengths and curvatures. After processing the collected driving data in the Frenet frame and considering the free play of a real car’s steering system, it was interesting to observe that the shape enclosed by steering wheel angles and the coordinate axis was a trapezoid. Then, we defined four feature points, four feature distances, and one feature steering wheel angle, and the trapezoidal steering wheel angle (TSWA) model was developed by backpropagation neural network with the inputs were vehicle speeds at four feature points, and road curvature and the outputs were feature distances and feature steering wheel angle. The comparisons between TSWA model and experienced drivers, model predictive control, and preview-based driver model showed that the proposed TSWA model can best reflect the steering features of experienced drivers. What is more, the concise expression and human-like characteristic of TSWA model make it easy to realize human-like steering control for autonomous vehicles. Lastly, an autonomous vehicle composed of a nonlinear vehicle model and electric power steering (EPS) system was established in Simulink, the steering wheel angles generated by TSWA model were tracked by EPS motor directly, and the results showed that the EPS system can track the steering angles with high accuracy at different vehicle speeds.

The increase of four-wheel tractor maneuverability

Along with the positive turning qualities, the shortcomings of three-wheeled tractors, associated with their instability, limited traction and coupling qualities and low total load capacity of tires, were noted. (Purpose of the study) The purpose of the study is increasing the maneuverability of a four-wheel universal row-crop tractor, ensuring minimal loss of productive areas in the headland zone at the edges of irrigated areas with cotton and other crops. (Materials and methods) The works on increasing the maneuverability of four-wheeled universal row-crop tractors are done at the Design and Technology Center for Agricultural Engineering. By increasing the angle of rotation of the steered wheels, the conditions to achieve a minimum radius of rotation of the tractor are created. (Results and discussion) There was developed a new design of the steering drive steering trapezoid of the universal row-crop tractor, where each half of the front cut symmetrical thrust from the side of the plain arm is shaded by a spring-loaded end disk, freely placed inside the hinged plain arm of the cage. In this case, the cavities of the cage, separating the end disk, are made in the form of communicating vessels, and the end disk itself is made in the form of a piston-valve, resting against the pressure of the spring on the saddle, cut at the bottom and connecting both cavities of the holder through two holes and ditches. (Conclusions) The new design of the steering trapezoid of the steering drive allows to increase the angle of rotation of the steered wheel during a turn, as a result when the tractor is turned, the axes of rotation of all three wheels in horizontal projection intersect at the intersection of the axes of symmetry of the fourth braked (right when turning «to the right» or left when «left turn») of the rear wheel. As a result, the intersection point of the axes of rotation of all the wheels is the center of the tractor’s turn, and it makes a turn around the braked rear wheel with a minimum radius and, thereby, eliminates the disadvantages of the well-known universal-row tractors.

Research on race car steering geometry considering tire side slip angle

The steering trapezoid designed according to the Ackermann steering geometry potentially causes excessive tire wear and affects the steering performance due to the large tire deformation resulting from large lateral acceleration. To address these problems, this article introduces a design method for a race car steering system that considers the tire side slip angles to optimize the target steering angle relation. First, a racing path was planned by genetic algorithm according to the given race track and race car driver characteristics. Next, the objective function of the ideal steering angle relation was constructed by introducing the Ackermann correction coefficient and establishing the modified Ackermann steering geometry model, considering the tire side slip angle. Then, a data acquisition experiment was designed, and the Ackermann correction coefficient was identified by the proposed simulation algorithm. Finally, the coincidence degree of wheel steering centers was defined as the evaluation index, which can be used to describe and evaluate the performance of the coordination for wheels’ movement. Simulation results show that the design method of the steering system effectively improves the handling stability of the race car and reduces the tire leaning-grind.

Human-like trapezoidal steering angle model on two-lane urban curves

With the rapid development of automated vehicles, there is currently a significant amount of automated driving research. Giving automated vehicles capabilities similar to those of experienced drivers will allow them to share the road harmoniously with manned vehicles, especially on two-lane urban curves. To represent the steering behavior of experienced drivers, a series of curve feature distances are proposed, which is determined by multi-regression. These series of curve feature distances are used to generate a trapezoidal steering angle model which imitates the steering behavior of the experienced test drivers. To verify the feasibility and human-likeness of the proposed trapezoidal steering angle model, the model is used with constant vehicle speed to plan a human-like trajectory which is tracked using model predictive control. The simulation results show that the proposed trapezoidal steering angle model is human-like and could be used to give automated vehicles human-like driving capability when driving on two-lane curves.

Maneuverability Analysis of a Novel Portable Modular AUV

ZFAUV is a novel portable modular AUV. There are four fixed thrusters at tail, and two tunnel thrusters are set at front. The maneuverability of ZFAUV is relatively high. It can turn around in situ, move lateral or move up/down vertical. The yaw and pitch can be controlled by tunnel thrusters or differential control of tail thrusters, but differential control will reduce the forward force. Different from propeller-rudder AUVs, the turning radius is related to speed forward: the smaller the speed forward, the smaller the turning radius. The minimum turning radius tends to be zero. The mathematical model is built first; then CFD is used to predict the thrust and torque of tail thrusters and tunnel thrusters. Through numerical simulation, zigzag maneuver analysis in horizontal plane, and trapezoidal steering maneuver analysis in vertical plane, the maneuverability of ZFAUV is obtained. The maneuverability of ZFAUV becomes worse with the increase of speed. The maneuverability of differential control is better than that of tunnel control. In the case of specific thrust distribution of tail thrusters and tunnel thrusters, ZFAUV can turn around in situ (the maximum angular velocity is about 24.1°/s), move lateral or move up/down vertical (the maximum velocity is about 0.4m/s). Finally, an example, PID parameters tuning, is given to illustrate the application of maneuverability analysis. The dynamic performance of ZFAUV can be quickly and accurately analyzed by mathematical method, which has important guiding significance for the choice of control strategy and experiments and also has reference value for the later development of AUVs.

Calculation and Optimization of the Optimal Region Value of Integral Trapezoidal Steering

This study aims to optimize the overall mechanism size of trapezoidal steering. A mathematical model is established and optimized in combination with its working characteristics. The objective function is the objective function of the actual momentary position of the vehicle and the error of Ackermann's instantaneous position, so that the actual instantaneous position in the theoretical instantaneous position near the maximum fluctuations in the minimum is close to the ideal Ackermann steering mechanism. Through the numerical experiment method, the instantaneous center position curve is simulated and the length of the trapezoidal pole is taken as the optimization target and the optimal area value. Results show that selecting the length of the steering mechanism in the optimal region is reasonable. The numerical experiment is compared with the theoretical mathematical model, and the optimal region is considered. The method is validated by introducing the existing calculation parameters and drawing the ideal deviation curve of the optimized steering. This study provides a normative guidance and basis for the design of trapezoidal steering mechanism.

A New Steering-by-Wire System Driving by Electric Wheels

For electric power steering is weak and can not be used in heavy vehicles. In order to solve this problem, according to the characteristic that the driving torque of left and right steering wheel can be independently controlled in electric wheel driving vehicle, a new non-trapezium-steering system has been proposed based on electric wheel driving and powering in this paper. This system makes use of the steering torque around the kingpin from electric wheel driving, and is controlled by steering constraint mechanism. Steering system force analysis was conducted to analyze the feasibility of the system in theory. On this basis, a small prototype vehicle was designed. With the use of Bluetooth wireless serial chip and STC12c5a60s2 microcontrollers, the steering-by-wire system lower computer was developed. With the LabView software, the upper computer system was developed in notebook computer. With these two systems, the steering system can conduct data acquisition and control. To verify the performance of the system, the steering angle step input test while vehicle is stationary, the steering angle step input test at low running speed were carried out respectively on the prototype vehicle. Results of steering wheel turning angle and wheel rotation rate show that non-trapezium steering-by-wire electric wheel driving power system can complete steering operation in a variety of conditions, and after removing steering trapezium, each wheel can be separately controlled for steering, and easy to implement multi-mode steering.

Optimization of Integral Steering Trapezoid of Commercial Vehicle Based on MATLAB

The good integrated steering trapezoid of the commercial vehicle can reduce the running resistance, making the steering portability, and reduce tire wear. According to the Ackerman principle, establish the outer wheel theory and practice angle deviation minimum, which is as objective optimization mathematical model. Optimizing two important parameters of the steering trapezoid arm value and the steering trapezoid arrangement angle by the optimization toolbox of MATLAB. After optimization, the value of the actual the inner wheel angle deviation between the theoretical is smaller, so the steering characteristic has been significantly improved.

Design of Steering Trapezoidal Mechanism for FSC Racing Base on Matlab

The design of steering trapezoidal mechanism is one of the important aspects of the vehicle steering system. Every parameterin steering trapezoidal has significant influences on the steering performance, stability and tire service life of the vehicle.Based on the analysis of the relationship of the inside and outside wheel angle by analytic method, Matlab software can be used to design FSC racing steering trapezoidal mechanism. Considering the conditions of the automobile race,the corresponding parameter of the steering trapezoid is designed to make the relationship of the l wheel angle close to Ackermann geometry relationship, which reduces the wear of tires, ensuring good steering performance and holding the road so well.

Optimization of the FSAE Car Steering Trapezoid

Steering system is important to the FSAE vehicle performance. And it’s necessary to optimize the steering trapezoid as well. According to the mentioned problem, the steering trapezoid is designed for the special circumstances of the track in this article. the steering mathematical model is established and optimized using the least squares method in the MATLAB Optimization Toolbox to improve the steering stability of the car. After manufacturing and testing the FSAE car prototype, the experimental and optimal results are compared, which indicates that the design of the steering trapezoid mechanism reduce tire wear and protect good steering and grip performance.

Optimization Design of Single Steering Trapezoid Mechanism of Vehicle Based on MATLAB

Firstly the optimum mathematical model of single steering trapezoid mechanism of vehicle was established gradually through selection of variables, setting constraints, determination of objective function. And then the optimum calculation is carried out with MATLAB programming in the case of EQ1092, and the problem occurring in actual operation that the optimum results changed with initial points was solved. In the end the further optimum research direction of this mechanism was intuitively pointed out through visualization and sensitivity analysis of results.

Optimal Design of Basic Parameter of Disconnected Steering Trapezoid

In the design of disconnected steering trapezoid, the Fmincon function of MATLAB optimization toolbox is used to optimize its basic parameters. First, establish the optimal mathematical model. Second, obtain wheel angle curve of inside and outside steering by least-squares fitting. Finally, compare the curve with the ideal Ackerman geometric curve to get the optimization parameters of disconnected steering trapezoid. The example of optimized design validated that the actual curve of deflection angle of the both sides of steering wheel was almost close to perfect Ackerman geometry curve, it ensures the steering of wheel do pure rolling in the common conditions, which reduce tire wear

Kinematics of а four-link steering trapezium and prognostication of its раrаmеtеrs

Kinematics of а four-link steering trapezium and prognostication of its раrаmеtеrs

Full-scale Measurement of Frequency Response Characteristics of Ships in Steering

This paper shows the results obtained on actual ships by using the method presented before in “A New Procedure of Manoeuvring Model Experiment”. The purpose of this paper is to determine these four characteristic constants K', T1', T2' and T3' of actual ships by means of frequency response analysis of a parallel shift manoeuvring and trapezoidal steering tests with fixed periods. This procedure gives enough informations of frequency response characteristics of a ship at practically important frequencies.As an additional attempt this paper deals with a ψ-ψ phase plane analysis on a parallel shift manoeuvre to determine the characteristic constants K', T1', T2' and T3'.Full-size experiments were carried out for eight actual ships, ranging from a 360 GT training ship to a 220, 000 DWT oil tanker.The conclusions obtained are that : 1) the combination of the parallel shift manoeuvre and periodic trapezoidal steering is a promising procedure for full-size steering test to determine the steering characteristic constants K', T1', T2' and T3'.2) both steering tests mentioned above are also applicable to the phase plane analysis, and this analysis can be used to determine the reasonable characteristic constants together with the frequency response analysis.3) the steering transfer function, Ys (iω), obtained from the frequency response analysis in the intermediate frequency range provides useful data in connection with K'T3'/T1' T2' to determine whether the course keeping ability, especially in the case of the automatic steering, is sufficient.