Hydraulic Steering Systems Research Articles

Reliable ships: A fuzzy FMEA based risk analysis on four-ram type hydraulic steering system

Hydraulic steering systems are vital for safe and efficient navigation in maritime vessels. Failures in these systems can pose serious operational and safety risks. This study uses fuzzy Failure Modes and Effects Analysis to assess risks in a four-ram hydraulic steering system commonly used in ships. A total of 47 failure modes of the hydraulic system were identified and analyzed using domain expert input to improve the accuracy of the risk assessment. Fuzzy input and output variables are developed, followed by the construction of membership functions, a rule base, and an inference engine to compute the Fuzzy Risk Priority Numbers (FRPN). Based on the calculated FRPN values, all failure modes are ranked, with the top ten highlighted and detailed in the Discussion chapter, which concludes with recommendations for control and prevention. It was found that the most critical failure mode is “insufficient system pressure” due to defective hoses, pipes, and connectors (FRPN 6.59). The results of this study provide practical benefits to the maritime industry by enabling more precise risk identification and mitigation strategies. This approach facilitates effective maintenance scheduling, enhances system reliability, reduces operational downtime and maintenance costs, and ultimately improves the safety and efficiency of ship navigation systems.

Теоретические исследования гидросистемы рулевого управления строительных и дорожных машин с усилителями потока

The article presents the results of theoretical studies of the functioning of flow amplifiers, the purpose of which is to increase the useful power of the hydraulic steering systems of heavy construction and road machines, which is especially important when upgrading existing equipment and designing a new one. Flow amplifiers allow to increase the supply of working fluid to the hydraulic cylinders for turning a multiple of the dosed volume by the dosing pump. A distinctive feature of the study is the consideration of two flow amplifiers of throttling and volumetric types, working in pairs. The design, the principle of operation are described, the main calculated dependencies are presented, on the basis of which mathematical modeling was carried out. To evaluate the qualitative and quantitative characteristics of the amplifiers, graphs of transient processes in the steering hydraulic system, as well as the static characteristics of the flow amplifiers, were obtained. The analysis of the obtained dependencies showed acceptable accuracy and quality of the hydraulic system. The results obtained can be used in the synthesis of such systems.

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.

Concept and Preliminary Simulations of a Driver-Aid System for Transport Tasks of Articulated Vehicles with a Hydrostatic Steering System

Heavy-wheeled vehicles with articulated hydraulic steering systems are widely used in construction, road building, forestry, and agriculture, as transport units and tool-carriers because they have many unique advantages that are not available in car steering systems, based on the Ackermann principle, such as—high cross-country mobility, excellent maneuverability, and high payload and lift capacity, due to heavy axles components. One problem that limits their speed of operation and use efficiency is that they have poor directional stability. During straight movement, articulated tractors’ deviate from a straight line and permanent driver correction is required. This limits the vehicles’ speed and productivity. In this study, we describe a driver-aid system concept that would improve the directional stability of articulated vehicles. Designing such a system demands a comprehensive knowledge of the reasons for the snaking phenomenon and driver behaviors. The results of our articulated vehicle directional stability investigation are presented. On this basis, we developed models of articulated vehicles with hydraulic steering systems and driver interaction. We next added the stabilizing system to the model. A simulation demonstrated the possibility of directional stability improvement.

Multi-objective optimization in the vibration characteristics of a hydraulic steering system using a conservative and feasible response surface method

ABSTRACTThis article addresses the approximate multi-objective optimum design of an automotive hydraulic steering system based on a multi-body dynamics analysis. The design problem of a hydraulic steering system was formulated to determine the design dimensions of a steering mechanism that is able to estimate the multi-objective Pareto-optimal solutions of weight and vibration frequencies that are subject to the dynamic response constraints of the main steering components. The multi-objective Pareto-optimal solutions were calculated using the non-dominated sorting genetic algorithm-II (NSGA-II) based on various approximate models, and reviewed in terms of exploration performance and constraint feasibility. The multi-objective Pareto-optimal solution characteristics according to the approximate model were reviewed to identify a proper approximate model for the engineering design of a hydraulic steering system. The results of the Pareto solution from the proposed optimization methods could improve the vibration performance as well as the weight reduction of hydraulic steering systems.

Design and Experiment on Integrated Proportional Control Valve of Automatic Steering System

According to the requirements of tractor automatic steering hydraulic system, a proportional integrated control valve was designed. Based on the non-linearity of the hydraulic system, the state equation of the integrated proportional control valve that works in the open-center hydraulic steering systems was established. With the establishment of the MATLAB/Simulink models, the static and dynamic performance of the integrated proportional control valve were simulated. Furthermore, the indoor test platform was built on the basis of the proposed test scheme, on which the properties of steady flow, load flow and pressure loss of the integrated proportional control valve were analyzed. The simulation and experimental results show that the valve flow can be better to follow the drive voltage; when the spool opening unchanged, load step change, the simulation and test results of the flow is about 10L/min. The differential pressure relief valve pressure compensation performance is better. Finally, the actual test of the proportional integrated control valve is carried out. The experimental results show that the average deviation of the target tracking is less than 2.192° and the maximum deviation is less than 2.44°. The valve proposed in this study performed well referring to the tracing and quick response characteristics, which meets the requirements of tractor navigation control.

H∞-control of a rack-assisted electric power steering system

Electric power steering (EPS) is more and more in use for passenger cars. Compared with hydraulic steering systems there are many advantages, such as reduced CO2 emissions and the possibility to use the EPS motor torque for advanced driver assistance systems. One task of the steering system is to give the driver an adequate steering feel. This includes providing road feedback and the right level of assistance torque. This article describes the steering torque control of a rack-assisted EPS. The controller's task is to follow a reference steering torque quickly and accurately. First, a mechanical model of the EPS is shown. Then, an H∞-controller is designed, implemented and compared with other steering torque controllers. As steering torque discontinuities are a topic when looking at new control algorithms, the phenomenon and its cause are analysed using a detailed mechanical model. The results of this analysis are considered in the controller design.

Torque overlay for hydraulic steering systems

With its intelligent Hydraulic Steering Assist “iHSA”, tedrive Steering has succeeded in developing a hydraulic steering system with a functional scope that is analogous to electric power steering. The option of demand-oriented volume flow control also opens up the possibility of saving CO2 and fuel beyond the levels known today.

Mathematical Modeling and Nonlinear Controller Design for a Novel Electrohydraulic Power-Steering System

This paper is concerned with the mathematical modeling and nonlinear controller design of a novel electrohydraulic closed-center power-steering system. After a short introduction to the requirements of modern power-steering systems, the construction of the power-steering system under consideration will be described. The main advantage of this construction is the enhancement of the overall energetic efficiency of the steering system and the possibility of a variable steering assistance while keeping the good steering feeling of traditional hydraulic steering systems. Based on a detailed mathematical model of the essential components of the system, it is shown how some of the parameters of the system can be chosen to achieve an optimal dynamic behavior of the closed-loop system. The controller design proceeds in two steps: first, a nonlinear controller for the assistance force based on the differential flatness property of the system is designed, and afterwards, a steering torque controller using an impedance matching design is derived. Finally, measurement results of a test stand show the good performance and the robust behavior of the proposed control strategy

Modelling and Control of An Electromechanical Steering System in Full Vehicle Models

In the automotive industry, electrical and electromechanical components and systems become more and more important. In comparison with commonly used mechanical and hydraulic systems they offer a large number of advantages with respect to efficiency and flexibility, for example. Therefore, conventional hydraulic steering systems are increasingly being replaced with electromechanical ones. Currently, different concepts of electromechanical steering systems are being developed. In this work an electromechanical steering system with double pinions is modelled based on a uniform theory for discrete electromechanical systems. This steering system is implemented into a multi-body full vehicle model and a control scheme has been developed. Subsequently, the performance of the whole electromechanical system, and especially the behaviour of the controller, has been tested with different handling manoeuvres.

New generation of electrically powered hydraulic steering system

Electrically powered hydraulic steering systems (EPHS) have been in mass production for approximately six years. They have been and still are very successful in the market as they follow the trend of supplying fully assembled and tested steering modules as well as meeting increasing demand for engine independent electrically powered systems. During the next few years, stricter legislation limits will be introduced in respect to emission and energy consumption. Furthermore, increasing demands regarding the dynamic performance of steering systems are requested. In the case of EPHS this can lead to a conflict of goals. This paper illustrates the main important system parameters and demonstrates how TRW’s new generation of electrically powered hydraulic steering, Generation C, combines optimal dynamic performance and low energy consumption.

Electronically controlled: Rear axle steering

Currently the technology of steering systems is experiencing major changes. In car applications beside the hydraulic rack and pinion steering, the fully electrically assisted steering systems are getting popular more and more. Also hydraulic steering systems superposed by additional electronic systems are gaining in the race of new developments. This tendency to electrification can also be observed in the commercial vehicle industry. In the following we want to highlight how ZF Lenksysteme, together with vehicle manufacturers, is leading into this new age of steering.

Applications of Robot Technology to the Paper Making Industry

Marol Co., Ltd.; well known for the manufacturer of Marol Brand hydraulic steering systems, autopilot and engine remote control systems for marine use, also designs and manufactures special purpose robots for industrial use. The company introduces three of their custom applications for the paper making industry.(1) Palletizing Robot for Handling Carbon-less Duplicating Paper RollsThis was developed to grip the outside of the roll efficiently without any transference and to handle rolls of different sizes and weights at random.(2) Custom Designed Automatic Grinder/Cleaner for Backing Roll of Existing CoaterThis was developed to clean the surface and remove scratches from Backing Roll. The device can be operated during operation and the surface of the roll can be kept clean as required. The device has functional flexibility so it can be operated under various conditions.(3) Custom Designed Automatic Grinder/Cleaner for Heat Roll of Existing Soft CalendarResearching various materials led to the development of this grinder that can withstand heat and grind the roll to remove contaminant and finish the roll to the required surface roughness. The device can be operated during operation and the surface of the roll can be kept clean as required. The device has functional flexibility so it can be operated under various conditions.