Posture Control Study On The Lifting Mechanism Of Automatic Catwalk

In the process of continental scientific drilling,,It is often necessary to transport hundreds of drill pipes between the drilling platform and the ground.This part of the work mainly rely on human work,which is not only inefficient,but also dangerous and easy to cause many personal accidents.At present,a part of the domestic well site can make some semi automated migration tool,but its relatively low efficiency and inconvenient operation cannot meet the needs of the production.Foreign technology in this field is relatively mature,but its equipment is mainly used in the field of ocean drilling.With the continuous development of modern automation technology,the research on the special equipment for the transportation of drilling tools in the upper and lower platforms has been put on the agenda.This paper is based on a sub subject of the national deep detection technology and experimental research(SinProbe-09-05)-" manufacture of full hydraulic automatic catwalk ".In this paper,the emphasis focus on the lifting mechanism of the equipment,where the control strategy of hydraulic cylinder position about brace strut is analyzed.First of all,this paper introduces the structure,working principle and process of lifting mechanism,and discusses the important role of the hydraulic cylinder rod position control,then lead to several main sections of this article.(1)Research on the electro hydraulic proportional control systemThis load sensing system is set up through the load sensing pump,which is used to adapt to the changing external load of the several different actuators.The device can not only realize the simultaneous operation of a plurality of actuators,but also can achieve the proportional control of flow rate.It is usually used in conjunction with the load sensitive technology to meet the requirements of multiple actuators in the control of system.This paper focus on the mathematics model of un-symmetry hydraulic cylinder controlled by proportional valve.This mathematical model is combined with the proportional valve and the sensor through the PLC controller to constitute the control system to grope for the transfer characteristics of the control system.(2)The design of fuzzy controller:According to the measured error and the error change rate,the fuzzy control rules are designed in the fuzzy controller to achieve the online self-tuning of PID control parameters.According to the actual needs,the membership function is selected by the triangle function,and the fuzzy inference module is selected by Mamdani method,The defuzzification method is selected by centroid method.(3)Research on PID control strategy and fuzzy PID control strategyUnder the excitation of unit step function,the control effect of fuzzy PID control in this system is demonstrated by comparing the results with conventional PID control.Finally,in the actual choice of the control strategy of the system,the experimental results show that the fuzzy PID control strategy has better performance than the conventional PID control strategy.