Research On The Automatic Drilling System Of Hydraulic Continuous Flight Auger

As a kind of piling machinery, continuous flight auger holds considerable market share in piling foundation construction. Today, hydraulic continuous flight auger is facing some problems, one is that the drilling tools’ soil mechanics is not sufficiently studied. Another one is that the traditional feeding manner decreases the working efficiency dramatically. This dissertation aimed to solve these problems.Firstly, according to relative studies, the mechanical behavior in three-dimensional drilling condition is studied by applying the McKyes-Ali’s soil failure pattern. Based on Merritt-Mair’s model of soil conveying, the compacted-status soil’s screw conveying mechanism is analysed.Afterward, based on the soil mechanics researched above, a conclusion, that the drilling speed will be maximized by controlling the continuous flight auger to obtain the most permited torque, was put forward, and the corresponding control target and regulars were made.After that, an automatic drilling system using a proportional variable pump-controlled winch apparatus was specially designed for ZLB30-Y110. The mathematic model was built then, and its time domain analysis was completed in Matlab/Simulink environment. The results suggested the necessity of closed-loop control mode.Besides that, by using modular method, the dissertation devised PID controller for the inner circuit and the fuzzy controller for outer circuit uses. By establishing the whole simulation model in the MATLAB/Simulink environment, some crucial parameters suitable for the automatic drilling system were obtained, and achieved good control quality.Finally, through a large number of experiments and analysis, the soil mechanics of drilling tool and the automatic drilling effect were proved.