Hydraulic Power Steering System Research Articles

Data-Driven Decision-Making method for Functional Upgrade Remanufacturing of used products based on Multi-Life Customization Scenarios

With rapid changes in technology and customer preferences, functional obsolescence of used products poses serious challenges to resumed remanufacturing. Upgrade remanufacturing is a potential solution for dealing with the problems of functional obsolescence. The multi-attribute remaining life and customized life of the functional unit are critical elements of decision-making for upgrade remanufacturing solution, yet there are many possible scenarios for the multi-attribute remaining life and the customized life. The optimal solution varies with the various scenarios, which makes the decision-making for choosing the optimal solution of Functional Upgrade Remanufacturing (FUR) very individual and complicated. To this end, the paper proposes a Data-Driven Decision-Making (DDDM) method for FUR of used products based on Multi-Life Customization Scenarios (MLCS). MLCS describes the relationship between the remaining physical, technical, economic life and customized life. Firstly, the used product is decomposed into several functional units that are taken as the objects for upgrade remanufacturing, and the mapping between MLCS and decision-making for FUR is established through data mining. Then the DDDM method of Bayesian network is employed to inference, which is constructed based on historical data, and the solution with the largest posteriori probability is taken as the optimal solution. Finally, a case study on decision-making for FUR of a used mechanical hydraulic power steering system is demonstrated to validate the proposed method.

Modelling, parametrisation and validation of a truck steering-system to predict the steering-wheel torque

The prediction of the steering-wheel torque in a steering-system is a challenging subject. The steering-system of a truck consists of many components, including a hydraulic power-steering system. A model is developed that includes the most important components. A Wheatstone bridge is used to model the hydraulic valve system. A flexible supply hose and compressible fluid in the cylinder chamber are taken into account. The model is parametrised using test-bench measurements. The model is validated by means of additional measurements on the same test-bench. The model is verified for quasi-static conditions and up till a frequency higher than a driver will ever use. The predictions of the steering-wheel torque, steering-wheel angle and pressures in the system are accurate for high torque amplitude inputs. For small inputs the model is still able to predict the steering-wheel torque with an error smaller than 10%.

Characteristics investigation and verification of permanent magnet slip coupling for hydraulic power steering application

Permanent magnet slip coupling (PMSC) is a kind of contactless transmission device with the advantages of clutch function, continuous speed regulation and no mechanical wear. The PMSC was introduced into the hydraulic power steering system (HPS) to regulate the steering pump speed so as to improve the steering stability and reduce the energy consumption. To evaluate the designed PMSC electromagnetic characteristics and dynamic characteristics of the PMSC were investigated and verified. Two-dimensional finite element model of the PMSC was built to investigate the electromagnetic characteristics. The simulation results of induced electromotive force, induced current and electromagnetic torque demonstrated that the PMSC had excellent electromagnetic characteristics. The speed regulation circuit of the PMSC was developed to investigate the dynamic characteristics. The results indicated that the PMSC had excellent dynamic characteristics under the condition of high load, inferior dynamic characteristics under the condition of low load. The bench tests were carried out to verify electromagnetic characteristics and dynamic characteristics of the PMSC. It can be seen that the test results of the induced electromotive force and output speed of the PMSC were in consistent with the simulation results. The real vehicle tests were conducted and the results demonstrated that the permanent magnet coupling based electronically controlled hydraulic power steering system (P-ECHPS) greatly improved low-speed steering maneuverability and high-speed steering stability of heavy-duty vehicles.

Hybrid Model-Based Analysis of Underground Articulated Vehicles Steering Characteristics

Owing to the harsh environment of underground mines, autonomous underground articulated vehicles (UAVs) with precise control and positioning system are particularly important. However, the ambiguity of steering characteristics hinders the development of UAVs. This study presents a model-based method to uncover the steering characteristics of a UAV. Firstly, a hybrid model of UAV was established, which included a dynamic model of articulated frames and a model of the hydraulic power steering system. Secondly, a field test of a typical UAV, a load-haul-dump (LHD) with 4 m3 capacity, was carried out. In order to verify the correctness of the established model and the accuracy of the involved parameters, the field test results were used to verify the dynamic model in time and frequency domains. Then, the steering characteristics of the UAV were uncovered based on the verified hybrid model, and the results showed that the increased load would increase ‘oversteering’ under the same articulation angle and that the error of trajectory exceeded 0.3 m. In addition, the deviations of trajectories between the two frames were revealed during the transient steering process, and the maximum deviation reached 0.21 m when the velocity was 2 m/s and the articulation angle was 15°. The comprehensive results indicate that the steering characteristics of UAVs cannot be ignored in regard to precise autonomous control and positioning.

Modeling and performance evaluation of a heavy-duty vehicle based on the hydraulic power steering system

In most mathematical models that are presented for vehicle performance analysis, the dynamic role of the steering system is ignored and causes the steering effect on the vehicle overall response to be neglected. In this article, the main goal is the performance evaluation of a four-axle heavy-duty vehicle using the modeling and simulation of the vehicle and the hydraulic power steering (HPS) system. For this purpose, using Newton’s method, a 20-degrees-of-freedom (20-DOF) nonlinear model of the heavy vehicle is developed, and verified by the TruckSim software results. Then, the comprehensive 4-DOF model of the HPS system, including the steering handwheel angle, rack displacement, and left- and right-hand wheel angles, is presented. Finally, the dynamic model of the heavy-duty vehicle and the HPS system are combined and a 24-DOF dynamic model is simulated in MATLAB software. In order to evaluate the vehicle performance, the simulation on two maneuvers, namely parking and low-speed lane change maneuvers with load and no-load, are carried out. The simulation results demonstrate the desirable performances of the heavy vehicle based on the HPS system on the parking and low-speed maneuvering. Also, the research results provide a better understanding of the vehicle handling considering the nonlinear model of the heavy-duty vehicle based on the HPS system.

ANFTS Mode Control for an Electronically Controlled Hydraulic Power Steering System on a Permanent Magnet Slip Clutch

There are various uncertain factors such as parameter perturbation and external disturbance during the steering process of a permanent magnet slip clutch electronically controlled hydraulic power steering system (P-ECHPS) of medium and heavy duty vehicles, which is an electronically controlled hydraulic power steering system based on a permanent magnetic slip clutch (PMSC). In order to avoid the immutable single assistance characteristic of a hydraulic power steering system, a PMSC speed-controlled model and P-ECHPS of each subsystem model were studied. Combined with non-singular terminal sliding mode and fast terminal sliding mode, an Adaptive Non-singular Fast Terminal Sliding (ANFTS) mode control strategy was proposed to control precisely the rotor speed of the PMSC in P-ECHPS, thus achieving better power control for the entire P-ECHPS system. The simulation results show that adaptive nonsingular fast terminal sliding mode control enables PMSC output speed to track the target speed. Compared with the non-singular terminal sliding mode control and the ordinary sliding mode control, the convergence speed has been improved by 66.7% and 84.2%, respectively. The rapid control prototype test of PMSC based on dSPACE (dSPACE is a development and verification platform based on MATLAB/Simulink software.) was carried out. The validity of the adaptive NFTSM algorithm and the correctness of the offline simulation results are validated. The adaptive NFTSM algorithm have better robustness and can realize variable assist characteristics and save energy.

Design optimization of vehicle EHPS system based on multi-objective genetic algorithm

Electric hydraulic power steering (EHPS) system has been widely used in large and medium cars, which plays an important role in determining the energy loss, driving safety and driving comfort of vehicles. This work mainly discusses the parameter design of the EHPS system based on the multi-objective optimization method. Since there is no explicit standard for the performance indexes of EHPS system, this work takes the energy consumption, steering road feel, steering sensibility and steering stability as the main performance indexes of EHPS system. The quantization formula of each performance index is explored and deduced. Based on these, a multi-objective optimization model is established. Then, the non-dominated sorting genetic algorithm-III based on fitness function (NSGA-III-FF) is proposed, which has better convergence than the original non-dominated sorting genetic algorithm-III (NSGA-III). Besides, the technique for order preference by similarity to an ideal solution (TOPSIS) is applied to select the ideal optimization solution. Simulation results show that the NSGA-III-FF enhances the comprehensive performance of the EHPS system, which can successfully achieve the goal of multi-objective optimization for steering flexibility, steering road feel, and steering energy loss while ensuring the steering stability.

A Hierarchical Strategy for the Electro-hydraulic Coupling Steering System on Commercial Vehiclescommercial vehicles, electro-hydraulic coupling steering, characteristic curve, hierarchical strategy

In order to improve the steering performance of commercial vehicles, this paper investigates a novel electro-hydraulic coupling steering (EHCS) system based on the electric power steering (EPS) system and the hydraulic power steering (HPS) system. A hierarchical strategy is proposed for the EHCS system, including a mode judgment controller, an assistance controller and an alignment controller. Fuzzy rules are established in the assistance controller to match the electric and hydraulic power assistance curves, so as to achieve a good assistance effect. The proposed EHCS system and its control strategy are validated in the co-simulation of the Simulink and the Trucksim, the results of which indicate a great improvement in the steering portability and self-alignment, compared with the EPS and the HPS.

Design Optimization of Vehicle EHPS System Based on Multi-objective Genetic Algorithm

Electric hydraulic power steering (EHPS) system has been widely used in large and medium cars, which plays an important role in determining the energy loss, driving safety and driving comfort of vehicles. This work mainly discusses the parameter design of the EHPS system based on the multi-objective optimization algorithm. Since there is no explicit standard for the performance indexes of EHPS system, this work proposes to take the energy consumption, steering road feel, steering sensibility and steering stability as the main performance indexes of EHPS system. Based on these, a multi-objective optimization model is established with the non-dominated sorting genetic algorithm-III based on fitness function (NSGA-III-FF), which has better convergence than the original NSGA-III. Simulation results show that NSGA-III-FF enhances the comprehensive performance of the EHPS system, which can successfully achieve the goal of multiobjective optimization for steering flexibility, steering road feel, and energy loss while ensuring the steering stability.

Vehicle Dynamics Modeling and Electronic Stability Program/ Active Front Steering Sliding Mode Integrated Control

AbstractChassis integrated control can significantly improve vehicle handling stability and comfort. Because of the complexity of the problem, it has attracted significant research attention. We built a vehicle nonlinear dynamic model with multi‐degree freedom, including body movement, wheel movement, and electronically controlled hydraulic power steering system. We compared the magic formula tire model, Dugoff tire model, brush tire model, and LuGre dynamic friction tire model and steady model. The precision of the model was verified by a comparison between simulation results and the real vehicle test results. Then, based on the vehicle dynamics model, an AFS (active front steering) controller was designed based on sliding mode variable structure control, and an AFS and ESP (electronic stability program) integrated coordination controller was proposed. Finally, based on the nonlinear tire model and multi‐DOF (degree of freedom) vehicle model, sinusoidal and step steering angle input simulation analysis was proposed on different road friction coefficients. The results show that the vehicle has better response characteristics with coordinated control strategy when compared with AFS and ESP only control. The evidence suggests that the proposed integrated control system in this paper can improve vehicle stability and safety.

An investigation on the energy-saving effect of a hybrid electric-power steering system for commercial vehicles

This article describes an investigation on the energy consumption of an alternative hybrid electric power steering system. The conventional hydraulic power steering system that is widely used in commercial vehicles can provide high steering-feel and reliability performances. However, since the combustion engine drives the pump, the hydraulic power steering system is energetically inefficient. To cope with this disadvantage of the hydraulic power steering system and to provide a technical base for the steering-related advanced driver assistance system, the Hybrid electric power steering system offers a solution for heavy commercial vehicles. The “Hybrid” of the title means that, for heavy commercial vehicles, the electric power steering system and electro-hydraulic power steering system are integrated in a ball-nut steering system. In this paper, to verify the energy-saving effect of the Hybrid electric power steering system, a dynamic model of the Hybrid electric power steering system was developed to estimate the energy consumption in the steering system. Furthermore, the fuel-efficiency test for the Hybrid electric power steering system were conducted while replacing the two steering systems (the conventional hydraulic power steering and Hybrid electric power steering system) in one vehicle on the chassis dynamometer for the proposed driving cycle. The driving cycle including the steering-angle profile has been developed to clearly investigate the effect on the energy-saving potential by the types of the steering system (hydraulic power steering and Hybrid electric power steering). The simulation results of the energy-consumption estimation showed that the hybrid electric power steering system can reduce the steering-system energy consumption by more than 50% under the proposed driving cycle. Also, the vehicle testing of the chassis dynamometer revealed that the Hybrid electric power steering system can improve the fuel efficiency of the vehicle by 1% for the specified driving cycle.

다중-파라미터 모델 예측 제어를 적용한 컬럼타입 전기식 동력 조향 시스템에 대한 시뮬레이션

This paper presents a multi-parametric Model Predictive Control (mpMPC) controller employed to improve the performance and robustness of a Column type Electric Power Steering (C-EPS) system. The EPS systems have been regarded as an important aid for drivers owing to their advantages over hydraulic power steering systems. An electric motor attached to the steering mechanism generates the assisted torque to reduce the required driver torque. The MPC has been more frequently used in automotive industries owing to its ability to fulfil hard constraints and anticipate future events; however, as this control scheme is based on online optimization, relatively large computational complexities are inevitably encountered. Therefore, the mpMPC has been suggested to reduce the complexities using a technique called multi-parametric Quadratic Programming (mp-QP), which considers the state vector as a vector of parameters. To verify the performance and the robustness of the proposed controller, a Linear-Quadratic Regulator (LQR) controller is also designed for comparison. A simulation via MATLAB/Simulink varying the parameters in a C-EPS system are conducted in this paper.

Experimental Investigation of Permanent Magnet Slip Clutch for Electronically Controlled Hydraulic Power Steering Application

Permanent magnet slip clutch is a new type of contactless transmission device with the main feature of great energy-saving potential while it has difficulty in controlling speed regulation. Permanent magnet slip clutch and corresponding DC chopper speed regulating circuit were designed based on the requirements of the transmission mechanism in a new type of electronically controlled hydraulic power steering system (E-ECHPS) installed on a heavy-duty commercial vehicle. In the load condition, the speed regulating was perfectly functional and the operation was stable. In this case, the prototype of permanent magnetic slip clutch was developed and the bench test system was constructed. The relationship between output speed and duty cycle of speed regulating circuit in high load condition was obtained by experiment. The speed regulating response could meet the requirements of E-ECHPS. The results show that permanent magnet slip clutch has a good function and a reliable performance of speed regulating, and it is of great theoretical guidance and practical reference value for the design optimization of contactless transmission devices.

Optimal design of variable assist characteristics of electronically controlled hydraulic power steering system based on simulated annealing particle swarm optimisation algorithm

In order to ensure that bus drivers have superior manipulation and good road feeling at different speeds, variable assist characteristics of electronically controlled hydraulic power steering system (ECHPS) were optimally designed based on simulated annealing particle swarm optimisation (SA-PSO) algorithm. First of all, characteristic points of assist characteristics curves were deduced via bus drivers' preferred steering torque and steering resistance moment at different speeds. Then the optimisation model of rotary valve parameters was built, with the minimum root of quadratic sum of the difference between hydraulic pressure at typical speeds and characteristic hydraulic pressure defined as objective function. The optimisation problem was solved by SA-PSO algorithm. To verify the design method, low-speed lemniscate and high-speed in-between steering simulations and experiments were carried out. The results showed that the low-speed steering portability and high-speed steering road feeling of optimised steering system were significantly enhanced.

Optimal design of variable assist characteristics of electronically controlled hydraulic power steering system based on simulated annealing particle swarm optimisation algorithm

Optimal design of variable assist characteristics of electronically controlled hydraulic power steering system based on simulated annealing particle swarm optimisation algorithm

An electronically controlled hydraulic power steering system for heavy vehicles

To remedy the existing problems concerning vehicle handling for the heavy vehicle hydraulic power steering system, this article investigates a type of electronically controlled hydraulic power steering system, which can realize variable assistance characteristics and improve high-speed steering feel. To this end, a controlled electrohydraulic proportional valve is mounted in parallel with the rotary valve to regulate the flow rate through the rotary valve on demand according to vehicle speed and steering rate. After a system description in terms of structure and working principle, mathematical modeling of the electronically controlled hydraulic power steering system, vehicle, and steering resistance is conducted. To realize accurate tracking of valve spool displacement under parameter uncertainty and external disturbance, an adaptive dynamic surface control scheme is proposed for the electrohydraulic proportional valve. Numerical simulations and field tests are performed to validate the effectiveness and applicability of the electronically controlled hydraulic power steering system. The results show that the electronically controlled hydraulic power steering system can significantly improve high-speed steering feel compared with the hydraulic power steering system while maintaining the similar performance of low-speed steering portability.

Electric Hydraulic Power Steering System Design Based on Electric Motor Coach of Mixed H2/H∞ Control

The Electric motor coach has become the focus of attention for its energy saving and green non-polluting, but it also poses a new challenge to feedback aspects of steering system and steering feeling. To enhance high-speed handling road sense, this article suggested using genetic algorithm to optimize mixed H2/H∞ system for boosting steering feeling control ability of hydraulic power steering system of electric motor coach based on analyzing electric hydraulic power steering system and feedback torque mathematical model of steering wheel. Simulation result showed that the accumulative error between torque feedback of steering wheel and wheel load torque is obviously reduced after optimization, and the feedback feeling of drivers to road sense has been strengthened.

Fuzzy logic control for vehicle stability control system with virtual prototype and experimental research

Electronic stability program (ESP) is an active safety system, which can keep a vehicle stable by traction or braking in extreme conditions and improve handling stability and driving safety significantly. In this paper, the vehicle subsystem key parameters were tested or identified through experimental means firstly, such as hydraulic power steering system, brake systems, shock absorbers and suspension hard points, wheels and tyres, engine and other components or subsystems parameters. And then the vehicle virtual prototype was built in multi-body dynamics software Adams/Car. According to the basic principles of vehicle stability control, the vehicle stability fuzzy-PID controller was designed in MATLAB/Simulink, and a combined simulation platform of control system and vehicle dynamics virtual prototype model was established. The model accuracy was verified by comparison of actual vehicle experiment and simulation under typical handling and stability control conditions. The results show that the ESP fuzzy-PID controller can effectively control the sideslip angle and yaw rate, and the vehicle trajectory following performance is satisfied. Finally, a winter field experiment was carried out, including double lane on snow roads and J-Turn on ice road. At the same time the original vehicle control algorithms are analysed.

Simulation and experimental research for the energy saving steering pump based on the special speed offsetting

In view of the performance steering pump application, this paper discusses the speed offsetting characteristics in specific speed range based on the action principle of a new variable displacement of the double-action vane pump. Under consideration of serious energy loss of an automotive hydraulic power steering system, the new pump has been designed and produced to overcome the problem. The key components of the pump were tested, and the test results show that the new pump with the speed offsetting can reduce the energy loss of the automotive hydraulic power steering system efficiently. The pump consumes about 20% less energy on average within the specific speed offsetting and hence the prosperous utilisation is expected.

Dynamics of electromagnetic slip coupling for hydraulic power steering application and its energy-saving characteristics

To improve high-speed road feel and enhance energetic efficiency of hydraulic power steering (HPS) system in heavy-duty vehicles, an electromagnetic slip coupling (ESC) was applied to the steering system, which regulated discharge flow of steering pump to realize variable assist characteristic as well as uniquely transfer on-demand power from engine to steering pump. The model of ESC was established and the dynamic characteristics of ESC were presented by the way of simulation and experiment. Upon the layout of the assist characteristics, output torque of ESC was derived. Based on the ESC model, the output torque characteristics of ESC were simulated under steering situation and straight driving situation, respectively. The consistency of simulated ESC output torque and the one deduced from assist characteristics verifies the correctness of the ESC dynamic model. To illustrate energy saving characteristics of ESC-HPS, energy consumption comparison of ESC-HPS and conventional HPS was carried out qualitatively and quantitatively. It follows that the energy consumption of ESC-HPS decreases by 50% compared with that of HPS.