The Steering Characteristic Research On A Multi-steering Axles' Vehicle

This paper is finished based on the FAW CA3412P2K15BT4 and FAW CA1312P21K2LT4,both designed by R&D center for the multi-steering axles automobile,which are the serial vehicles of 8x4. GB7258-2004,safety specifications for power-driven vechicles ,the People's Republic of China's standards,has issued on 12/7-2004,and bring into effect on 10/1-2004.it replaces the standards of GB7258-1997.Routeway circle test has been added in the new one. The author has studied and researched those items, worked at the steering system, and compiled computering programs to simulate the new added routeway test.From the calculated dates,we expect to get a character value,which may representate the power or capability of the vechicle. The work can be separated three parts as the following list: 1,Based on the created geometrical of the steering system,the author analyses and resolves the trapeziform machine in the space dimension,and educes the equations include the kingpin inclination,camber angle and the kingpin castor angle. In the design of turning-angle's computer program,the author applies two different ways to educe the space points'coordinates,that is the absolute way and the relative way;In the program,we can use dichotomy to answer transferring the relationship of the steering machine.For decreasing the compute times,the author provides the dichotomy's minimal interzone.The author compile the programs with C++ language.We can optimize the parts of steering machine useing the computer programs,such as the droparm and transfer-droparm,get a better character. 2,The technology of 4WS has been used in the truck,and 4WS can improve the response of the vehicles's dynamic statewhen the steering-wheel has a steering input.In a certain extent,4WS can remarkable improve the guide line of the transient response in the yaw angle speed and side acceleration.In addition,when the 4WS's vehicle drives a corner in a lower speed,the front and the rear wheel's turning direction may be opposite.That can reduce the cornering radius,consequently,the vehicle can get a more flexibility. Thinking about the affection of ackerman steer angle and the practice steering angles'relationship,the tire rolling angle,the rolling drag and the driving force,the author establishs a vehicle's movement model,which is based on the 8x4 series'vehicle with double steering axles.The author educe the model's movement equations,the unknown variables are the distance from the transient turning center to the last axle,the minimum turning diameter and the driving force.The flexibility has been evaluated according to the GB7258-1997. At the start of the minimum diameter's program,we should use the trapeform relations as the initial value, and input them to the equations.In the computer the turning diameter equation,we meet with the lineral and nonlinearal equation.Here,we choose the Gaus arithmetic to resolve the lineral equation and Imitate-Newton arithmetic and Montecarlo arithmetic to nonlineral one. 3,Applying the previous 8x4 movement model to routeway circle test, which has been added in the GB7258-2004,the author introduces a staff gauge circle preview in the test's simulated computer,and simulated the route way track,the vehicle's outer point satisfied with D1=25m and D2=10.6m is simulated.In the progress,the steering wheel turn a step angle by the staff gauge circle preview.At the same time,we monitor the outer points in the front and the rear vehicle,and the point nearest to the routeway circle center inside of the vechicle,we should also record the maximum sway value.Contrast the test dates'graph,we want to find a value,which can be use as the reference in the vehicle design ,or use as a character respresenting the automobile's capability.