Characteristic Analysis For Hydraulics Power Steering System Of Multi-axle Vehicle Based On VP Technology

The all terrain crane origins from Germany, its primary market is in Europe all the time. So development of its technology is relative mature. With rapid development of our national economy continuously in many years, it will impel the development of the engineer machinery powerfully, and then the demand of all terrain crane will increase obviously. Recently, a heavy-duty machine factory of engineering machinery group has successfully produced a series of international leading QAY25, QAY50, QAY130, QAY160, QAY200 all terrain crane. The steering axles of the vehicle are two or more than two, and the axles of the vehicle are more than three. Because of increase of the axles and weight, these objective factors make the steering course of the multi-axis hoist crane more complicated. So the technology of automotive power steering should be advanced.Power steering-system's performance quality is the gist for reliability and safety of the automotive steering-system. It consists of hydraulic power steering-system and electric power steering-system. But, hydraulic power steering-system is applied in heavy trucks. It is composed of power steering-gear and cyclical hydraulic system. According to hydraulic form, hydraulic power steering-system is divided into constant pressure and constant flow hydraulic power steering-system. According to the control valve structure, it is divided into spool valve type and rotary valve type. In this paper, taking a all terrain crane as the research object, introduced the composition and type, presented its research status. Performance simulation on the all terrain crane hydraulic steering system using Matlab/Simulink,ADAMS/View,ADAMS/Hydraulics software and so on is presented.The paper mainly includes the following contents:(1)Analyze the principle of power steering-system. Taking the steering system of a all terrain crane as a research object, calculations of some main components of the hydraulic power steering-system is given. (2)During the whole cyclical hydraulic system modeling, the organization of valve spool controlled hydraulic cylinder is the core part of the cyclical hydraulic system. In this article, the angle diamonds figure of the wheel is established, then the dynamic equation of the system is established which is based on the method of the transfer function. The imitation organization model can be established by the Simulink module of Matlab. Through the simulation, analyze dynamic and reliable capability, In view of the system dynamic and the reliable characteristic, we have carried on the time and frequency simulation, and found the influence parameter of the system stability and dynamic characteristic. The result indicated that, the system stability is good, the speed of response is quicker. The parameters that influences the stability and the dynamic characteristic have, power cylinder's area, the flowrate gain, the cylinder and the pipeline compression volume, the load quality, the elasticity coefficient and so on.(3)Due to the advantage of the new technology VP, The multi-body steering system model of a all terrain crane using ADAMS software was established, which contains body, steering control mechanism, steering linkage, recirculating ball and nut steering gear, power cylinder, ackerman steering, pitman arm, steering drag link, steering tie rod and so on. Because the power steering-gear is the key of the entire vehicle steering-system, we noticed that two movement relations of recirculating ball steering-gear.(4)The constant flow hydraulic power steering-system principle drawing and mathematical model of steering system is built up. Furthermore, the virtual hydraulic system is built by use of the hydraulic module of ADAMS software. According to the mathematical model of each component, the setting of the hydraulic components parameter can be done. Accordingly, the mechanical and hydraulic systems are integrated via the two-way cylinder.(5)According to the created mechamical and hydraulic virtual model, the imitation is combined. Before the imitation, the parameter is set, when the imitation is done, the changed curve can be observed accurately. For example, the angle of wheel, the flowrate of power steering-gear, the pressure of power steering-gear, the velocity of the cylinder, the pressure of the system, the force of steering tie rod on type-status. Based on the simulative result, we analyze the kinematics capability and dynamics analysis of steering system of the all terrain crane. The result express: The model has satisfied some technology specification, for instance, the ratio of motion, the system pressure, the system flowrate and so on. The data of simulation and the computed result are mutually steady to match, and so verified the accuracy of the model. Especially we get the curves of the force of the tie rod that the entire vehicle is turned under the typical condition.