The Research Of Electronically Controlled Hydraulic Steering System For The Third Axle Of Multi-axle Trucks

Multi-axle trucks have many shortcomings, such as its long turning radius, poor mobility, steering axle tire wear, poor handing and stability. As to correct these shortcomings, steering wheels must stay coordinated, they should meet the ackerman geometric relationship. Traditional Multi-axle trucks adopt steering transmission of hydraulic power system. Drive link steering system takes more space of the interior layout, and the drive link itself is prone to bending. The pitman arm and steering rod are prone to bending when trucks travel with heavy load.what’s more, the drive rod system may has swing phenomena and its stability is poor, these will affect the wheel angle and increase the wear on the tires.This graduation design is based on a8x2Multi-axle truck of an automobile enterprise, develops an electro-hydraulic steering system for the third steering axle.This paper designs a hydraulic control system and a cylinder which can be reliable mechanical self-locking in the median state based on the original centering cylinder by researching and analyzing the electro-hydraulic steering systemAt the same time, we designs and develops a third-axis steering controller based on Freescale microcontroller, including the design of hardware and software with PID algorithm. Finally, we build test bench according to the real vehicle, On the test bench and the actual car test,we have got more successful validation results.