Pressure Pile Driver Leveling Planning And Electro-hydraulic Automatic Control Study

In order to satisfy the requirement that accurate horizontality and rapidly elevating of the elevating platform of hydraulic static pile driver, based on the study of platform kinematics, this thesis have discussed the leveling programming and control method, and then developed a solenoid valve and proportional valve parallel connected and PLC control electro-hydraulic self-leveling system.Firstly, starting with structural analysis of the platform of hydraulic static-pile driver, conditions for leveling of the platform has been elicited. And based on this, the platform structure has been improved, so the platform could be leveled on the structure.Secondly, theoretical study has been conducted on kinematics of leveling platform deeply. Through theoretical analysis, the planning of leveling and programming of hydraulic cylinder movement have been ascertained and simulated by MATLAB to verify its reasonableness.Thirdly, for the specialist environment and work requirements of hydraulic static pile driver, hydraulic system of paralleling large diameter electro-hydraulic valve and small diameter proportional direction valve has been designed and modeled mathematically. Dead zone of proportional valve and non-linear features of electro-hydraulic valve have been analyzed. And the relation between stability conditions, steady error, and system parameters have been discussed theoretically.Fourthly, based on analysis of system, theoretical study and simulation has been done on control strategy, the PI control strategies for proportional valve and bang-bang control for electro-hydraulic valve have been ascertained. At the same time, the threshold value have been set form the analysis of switching property of the electro-hydraulic valve. Then through simulation, the impact of different parameters on system has been discussed, and the parameters have optimized by comparing data.Lastly, the PLC controller has been developed and programmed, and then the electro-hydraulic automatic-control has been tested. The results show that, the system not only can achieve rapid elevating of platform, but also meet requirements of accurate horizontality.