Research On Hydraulic Controlled Steering Technology Of Multi-axis Truck Crane

Based on the research in this paper,a steering control system with high control accuracy,flexible control,high transmission accuracy and convenience is developed.It is the purpose of this study to replace the steering technology of mechanical drag-link in the chassis of medium and large tonnage truck crane so that we can solve the problems of the multi-drag-link system,such as the difficulty in overall arrangement,large space occupied by the bar system,large deformation,poor control stability,poor maintenance and easily worn of the tire.The main contents of the thesis are as follows:(1)Kinematics optimization of steering mechanism.Based on the multi-body system dynamics,the steering mechanism model is established,the constraint and drive are set,and simulated,and the design is optimized.(2)According to the optimization analysis of the steering mechanism,establishing the steering principle of rear axle hydraulic control.Combined with the front steering Angle,the rear axle steering Angle that is controlled by steering hydraulic system when the vehicle runs at low speed,is manipulated through controlling the front axle mechanical steering.At the same time,according to the rotation Angle of hydraulic steering gear,the oil output is in quantitative proportion.When the vehicle runs at high speed,the rear steering device is in a no-load state.The system keeps the rear axle in a neutral position by locking the oil cylinder,locking valve,energy accumulator and other components to avoid the wheel swing caused by road impact load,thus ensuring the stability and reliability of the whole vehicle at high speed.(3)Establish the electrical logic control system of liquid follow-up steering.Study and design the monitoring technology of the middle position state of the wheel and adaptive control strategy of the rear axle wheel,detect the speed,oil cylinder pressureand the state of the wheel at real-time,through controlling the locking and unlocking of the middle position of the wheel,realizing the two steering modes of high and low speeds.(4)System manufacturing and test analysis.According to what have been discussed in theory,a multi-axle truck crane equipped with this steering system is designed and tested.By comparing the results gained from experiments with those from analysis,it makes sense to apply the method in engineering.The paper has 61 pictures,11 tables,and 65 references.