Vehicle Steering System Research Articles

Fault detection and fault-tolerant control of autonomous steering system for intelligent vehicles combining Bi-LSTM and SPRT

Fault detection and fault-tolerant control of autonomous steering system for intelligent vehicles combining Bi-LSTM and SPRT

Control Analysis of Vehicle Steering System based on Closed-Loop Control Algorithm

When a four-wheel vehicle turns and the steering centre of the front and rear wheels is one point, it is regarded as the theoretical optimal steering of the vehicle and the goal of optimal control. Aiming at the commonly used multi-link steering system, the system control was analysed, according to the structural characteristics and angle relationship. Based on the closed-loop control algorithm, the optimal control of the steering system was designed and analysed, according to the steering control quantity obtained by the target path and parameter feedback. At the same time, the state variables and prediction parameters of the system were analysed. Based on the actual vehicle and steering optimal control system, the changes of various parameters of vehicle operation under no-load condition and turning at 30 km/h were analysed and compared with the theoretical optimal value to verify the effectiveness of the control system. The results show that: the state variables of the control system are predicted by discrete analysis and half step integration, and the accuracy is high. In the steady state turning condition, with the lifting of the vehicle, the radius of the steering track gradually increases, and the vehicle shows obvious understeer characteristics. Under the two working conditions, the characteristic curves obtained by the steering control system are highly consistent with the theoretical values, and the peak error of the two is controlled within 5%, indicating the reliability of the optimal control algorithm, which provides a reference for such design optimization.

Path Tracking Control of Intelligent Vehicles Considering Multi-Nonlinear Characteristics for Dual-Motor Autonomous Steering System

In the path tracking control of intelligent vehicles, the traditional linear control method is prone to high tracking errors for uncertain parameters of the steering transmission system and road conditions. Therefore, considering the mechanical friction in the dual-motor autonomous steering system and the nonlinearity of tires, this paper proposes a path tracking control strategy of intelligent vehicles for the dual-motor autonomous steering system that considers nonlinear characteristics. First, a dual-motor autonomous steering system considering mechanical friction and the variation of tire cornering stiffness under different tire–road friction coefficients was established based on the structure of an autonomous steering system. Second, a tire–road friction coefficient estimator was designed based on a PSO-LSTM neural network. The tire cornering stiffness under different tire–road friction coefficients was estimated through the recursive least-square algorithm. Then, the control strategy of the dual-motor autonomous steering system was designed by combining the LQR path tracking controller with the adaptive sliding mode control strategy based on field-oriented control. Here, mechanical friction and the variation of tire cornering stiffness were considered. Finally, simulation and HiL tests validated the method proposed in this paper. The results show that the proposed control strategy significantly improves the tracking accuracy and performance of the dual-motor autonomous steering system for intelligent vehicles.

Speed-planning algorithm and super twisting control for autonomous vehicle steering system

Autonomous vehicle field has seen much development in recent years, especially with the appearance of new efficient control techniques focusing on longitudinal and lateral direction in order to follow a specified trajectory or path. This paper proposes a new systematic control technique to simultaneously generate a suitable speed profile and control the vehicle lateral motion through a predetermined path that considers different driving scenarios representing real-world driving. First, an extended-kinematic model for an autonomous vehicle is designed based on side-slip angle estimation. Then, the proposed technique uses a relationship between lateral error, heading error, and vehicle velocity to generate a suitable steering angle based on super twisting mode control. Second, a speed-planning algorithm is developed to control vehicle velocity. The algorithm uses a strategy for sharp curve identification; then it generates an adequate speed profile depending on the dynamic characteristics of these curves to ensure smooth motion of the vehicle through the whole trajectory. The obtained results from using a speed-planning algorithm with a super twisting controller prove the high performance of this control technique in terms of decreasing errors and respecting passenger comfort.

Failure analysis and finite element assessment of a torsion spring

The torsion spring is an important component for vehicle steering system. The torsion spring in this study was manufactured using high quality carbon structural steel. In order to study the failure mechanism of the spring, a series of experiments were carried out. All the collected evidences indicated that the spring fracture was due to fatigue crack propagation. At the same time, an obvious machining defect was observed on the inner surface of the ring. There are two crack initiation regions which are located at the areas near and opposite side of the machining defect. Under the cyclic loading induced by the repeated turning, the crack propagated and fractured finally. In order to analyze the effect of the machining defect on the fatigue failure, a computed tomography experiment was conducted. The precise characters of the defect were measured by computed tomography experiments. Then a finite element model was established according to the actual defect size and the stress distribution of the torsion spring was analyzed. The results showed that the local stress of the spring and the area of stress concentration are closely related to the machining defect and the gap between the spring and the two cylindrical objects. Under the actual condition of the torsion spring in service, the severe stress was located on the fracture location, which indicating that the machining defect is the efficient cause of spring failure.

Cooperative Optimization Design of Multi-axis Mining Vehicle Steering System

Cooperative Optimization Design of Multi-axis Mining Vehicle Steering System

Study on Shimmy Phenomenon on Two-wheeled Vehicle Steering System Considering Tire Dynamics

Study on Shimmy Phenomenon on Two-wheeled Vehicle Steering System Considering Tire Dynamics

Design of vehicle steering system testing training in augmented reality environment

Design of vehicle steering system testing training in augmented reality environment

Development of mathematical model for design of vehicle steering system

The vehicle steering system is one of the most important systems on the vehicle, both in terms of safety and performance. Based on the geometry of the steering trapezoid, the geometry of the suspension system, the alignment angles of the wheels, as well as the characteristics of the tires, a mathematical model for the design of the formula student vehicle "Road Arrow" steering system was developed. Based on the dynamic state of the vehicle, the mathematical model provides information on the stress of the steering system, the torque on the steering wheel and the slip angles of the steered wheels. The mathematical model was developed using the MATLAB software, and validation of the results was performed by comparing the results with the ones obtained by simulations in MSC ADAMS. Analysing the obtained results, it is possible to conclude that the average value of relative error of the stress is approximately 15%, for slip angles of the steered wheels is approximately 7%, and the error for torque on the steering wheel is approximately 6%.

Adaptive control of dual-motor autonomous steering system for intelligent vehicles via Bi-LSTM and fuzzy methods

In order to achieve better trajectory tracking of intelligent vehicle on different road surfaces, which include underling the weather of rain and snow, an adaptive tire cornering stiffness strategy (ACS) and a trajectory tracking autonomous steering control strategy were proposed in this paper. Firstly, the tire–road friction coefficient estimator was designed to obtain the tire–road friction coefficient based on Bi-LSTM neural network, then combining the tire cornering stiffness coefficient by fuzzy controller to obtain the online tire cornering stiffness. Secondly, considering the uncertainty of tire cornering stiffness, a trajectory tracking upper-level controller based on model predictive control (MPC) algorithm was proposed to calculate the optimal front wheel angle. Thirdly, in order to better adapt to various road conditions, a dynamic equivalent stiffness model is proposed to replace the self-aligning torque model during vehicle steering, and a lower-level controller for pinion gear target position tracking was designed based on the sliding mode control (SMC) algorithm. In addition, this paper also designed a dual-motor control strategy, which cooperates with the pinion gear target position tracking lower-level controller to quickly and accurately achieve the target front wheel angle. Finally, the simulation and HiL test results show that the proposed control algorithm greatly improves the trajectory tracking accuracy and stability of the intelligent vehicle on roads with different tire–road friction coefficients.

Coordination Control of Multi-Axis Steering and Active Suspension System for High-Mobility Emergency Rescue Vehicles

This study proposes a coordinated control strategy to solve the coupling problem between the multi-axle steering system and the active suspension system of emergency rescue vehicles. Firstly, an eleven-degree-of-freedom coupling model of an emergency rescue vehicle is established. Secondly, a dual sliding mode (DSM) controller is designed for the multi-axle steering system and a dual linear quadratic regulator (DLQR) controller is designed for the active suspension system. Finally, the coordinated control strategy is designed, and the weight values are selected using the fuzzy algorithm. Results show that compared with the individual control, the root mean square (RMS) value of the body roll angle, roll angle acceleration, and yaw angle acceleration with coordinated control are reduced by 16.89%, 29.08%, and 27.75%, respectively. The proposed coordinated control strategy effectively improves the handling stability and ride comfort of the vehicle.

Towards Active Safety Driving: Controller Design of an Active Rear Steering System for Intelligent Vehicles

To advance the active safety performance for vehicles, especially in extreme conditions, an active rear steering (ARS) control system is designed in this paper. A driver model is established to simulate the driving behaviour of a human driver who is in charge of the front steering control. In the ARS control system, the sliding mode predictive control (SMPC) approach is applied to the ARS controller design based on a 3 degrees of freedom (DoF) nonlinear vehicle model. In the ARS controller design, four kinds of active safety performances are considered, namely, path-tracking performance, handling performance, lateral stability, and rollover prevention. Furthermore, the priority of the four kinds of active safety performance is defined. According to the control priority, an event-triggered mechanism (ETM) is designed to adjust the SMPC controller of the ARS system to address different driving conditions. Finally, two simulation cases are conducted to evaluate the performance of the proposed ARS system. The results show that the ARS system is in favour of the active safety performance advancement for human drivers. Additionally, the comparative simulation indicates that the SMPC algorithm is superior to the fast terminal sliding mode control (FTSMC) algorithm.

The cascade optimal control of steer by wire system using hardware in the loop simulations

This paper aims to further improve the performance of the control system on the steer by wire (SbW) of vehicle steering system, by presenting the development of optimal control system strategy for lateral motion and yaw motion which is arranged in a cascade so that the vehicle can always be maintained on the desired trajectory. The control system strategy to be developed is fuzzy logic control (FLC) as a lateral motion control and proportional integral derivative (PID) control as a yaw motion control, and to obtain an optimal control system, the modified-quantum particle swarm optimization (MQPSO) optimization method is used. The simulations are carried out using hardware in the loop simulations (HILS) which involve hardware, namely; motor stepper actuator and rotary encoder to determine and monitor the direction of the front wheels which are applied to the vehicle dynamics model in a real time. HILS test results show that vehicle movement can be maintained according to the desired trajectory (double lane change) with an average continues-root mean square (C-RMS) error of 0.015366 for lateral motion and 0.014967 for yaw motion, the average C-RMS error is greater 23.75% for lateral motion and 28.18% for yaw motion against the results of the software in the loop simulations (SILS) test.

Predictive Control Applied to the Steering System of an Autonomous Vehicle

Predictive Control Applied to the Steering System of an Autonomous Vehicle

H-Infinity Observer for Vehicle Steering System with Uncertain Parameters and Actuator Fault

In this paper, an actuator fault diagnosis and reconfiguration problem is discussed for an uncertain vehicle steering system with external disturbances. Aiming at the factors affecting the control performance, a fault reconstruction strategy based on H-infinity observer is designed to improve the vehicle stability under complex conditions when the actuator fails. Firstly, aiming at the uncertain part caused by the road condition transformation, a mathematical model of dual input and dual output four-wheel steering system is established. Secondly, an augmented system is constructed in which the augmented state vector consists of the original state and actuator faults. Thirdly, the H-infinity observer is designed, and the gain of the observer is obtained by the Lyapunov function and linear matrix inequality. Finally, the effectiveness of the proposed strategy is verified by MATLAB/Simulink and Carsim co-simulation.

Research on Steering Vibration Analysis of Wheel Loader and Cushion Valve Design

At present, the wheel loaders on the market have steering vibration problems, which can be summarized as follows: the front frame and the cab vibrate violently at the beginning and at the end of steering. This paper analyzed the steering vibration mechanism by collecting the pressure at different positions of the hydraulic steering system and AMESim simulation. A cushion valve was designed to solve the problem of steering vibration. Finally, the prototype test was carried out and it was concluded that the cushion valve reduced the steering pressure starting shock by 50%, the stop vibration was reduced by 75%, and the suction problem no longer occurred. Further, the analysis provides theoretical and experimental basis for research on the steering system of loaders, and also provides new ideas for the design and optimization of vehicle steering systems.

Systematic Approach for Static Steering Effort Reduction through Linkages Optimization in Small Commercial Vehicles (SCV)

The steering system design of a vehicle is of utmost importance as it not only acts as an interface between the driver and the entire vehicle but also is one of the key vehicle sub system which accounts for vehicle overall performance including vehicle handling and stability. With the recent infrastructure development and changes been witnessed in doing commercial vehicle business to hub and spoke and to door to door logistics delivery are expecting improved vehicle performance particularly in small and light commercial vehicles segments (SCV and LCV) where the business demands are more for the movement of vehicle in narrow city lanes and sharp corners. Also, now driver comfort is considered one of the key factors before purchasing any commercial vehicle. Thus, having power steering in SCV’s and LCV’s has not only become a mandate but also the vehicle steering system performance should be such that the driver is easily able to maneuver the vehicle in narrow city lanes and corners. Through this paper a methodology has been derived wherein factors contributing for achieving static lock to lock maneuverability in a power steering vehicle are analyzed without overdesigning the hydraulic power assistance of the vehicle. The approach mainly focuses on LH/RH symmetric hydraulic pressure build up in the system by critically designing the steering system linkages hard points such as drop arm length, drop arm SAP angle, steer arm length, track rod arm’s length. Also, this study ensures that the derived hard points not only enhances hydraulic assistance in the steering system but also ensures vehicle to have least turning circle diameter (TCD) and enhanced tire life by having least Ackermann error.

Impact of Hydraulic System Stiffness on Its Energy Losses and Its Efficiency in Positioning Mechanical Systems

Hydraulic steering systems for mechanical devices, for example, manipulators or vehicle steering systems, should be able to achieve high positioning precision with high energy efficiency. However, this condition is very often not met in practical applications. This is usually due to the stiffness of the hydraulic system being too low. As a result, additional corrections are required to achieve the required positioning precision. Unfortunately, this means additional energy losses in the hydraulic control system. In this study, this problem is presented using the example of a hydraulic steering system for an articulated frame steer vehicle. This hydraulic steering system should provide the required directional stability for road traffic safety reasons. So far, this issue, connected mainly with the harmful phenomenon of so-called vehicle snaking behaviour, has not been solved sufficiently practically. To meet the needs of industrial practice, taking into account the current global state of knowledge and technology, Wrocław University of Science and Technology is performing comprehensive experimental and computational studies on the snaking behaviour of an articulated frame steer wheeled commercial vehicle. The results of these tests and analyses showed that the main cause of problems that lead to the snaking behaviour of this vehicle class is the effective torsional stiffness of the hydraulic steering system. For this reason, a novel mathematical model of the effective torsional stiffness was developed and validated. This model comprehensively took into account all important mechanical and hydraulic factors that affect the stiffness of a hydraulic system, resulting in the examined snaking behaviour. Because of this, it is possible at the design stage to select the optimal parameters of the hydraulic steering system to minimise any adverse influence on the snaking behaviour of articulated frame steer wheeled vehicles. This leads to minimising the number of required corrections and minimising energy losses in this hydraulic steering system. The innovative model presented in the article can be used to optimise positioning accuracy, for example, in manipulators and any mechanical system with hydraulic steering of any system of any mechanical parts.

Research on EPS system control strategy of SUV based on CarSim/Simulink

In order to solve the problems existing in traditional electric power steering system control methods, such as poor operation angle control effect, low system control accuracy and long control time, this study designed an electric power steering system control strategy of sports utility vehicle based on CarSim/Simulink. Firstly, the characteristics of electric power steering system are analysed, which provides the basis for subsequent control; then, the dynamic model of sports utility vehicle is constructed. On this basis, vehicle model is abstracted and simplified based on CarSim/Simulink software. Finally, according to the power assist characteristic curve model, the parameters such as steering wheel torque signal and vehicle speed sensor are optimised to complete the research on the control strategy of electric power steering system of sports utility vehicle. Experimental results show that the proposed method has a good effect on the operating angle control of SUV EPS system, the control accuracy of the system is always higher than 90% and the maximum time consumption is only 7 s.

Conflict and Sensitivity Analysis of Articulated Vehicle Lateral Stability Based on Single-Track Model

Lateral stability is quite essential for the vehicle. For the vehicle with an articulated steering system, the vehicle load and steering system performance is quite different from the passenger car with the Ackman steering system. To investigate the influence of the tire characteristics and vehicle parameters on lateral stability, a single-track dynamic model is established based on the vehicle dynamic theory. The accuracy of the built model is validated by the field test result. The investigated parameters include the tire cornering stiffness, vehicle load, wheelbase, and speed. Based on the snaking steering maneuver, the lateral stability criteria including the yaw rate, vehicle sideslip angle, tire sideslip angle, and lateral force are calculated and compared. The sensitivity analysis of the tire and vehicle parameters on the lateral stability indicators is initiated. The results demonstrated that the parameters that affect the lateral vehicle stability the most are the load on the rear part and the tire cornering stiffness. The findings also lay a foundation for the optimization of the vehicle’s lateral stability.