Adaptive electro-hydraulic system of ZMK5550TZJF50/120 truck-mounted drilling rig with WOB adaptive control function

The truck-mounted drilling rig is an ideal model for rescue drilling construction due to its strong mobility and wide process adaptability. The traditional truck-mounted drilling rig adopting the mode of hydraulic control and hydraulic drive has the problems of non-intuitive displaying of control parameters and many pipelines, which is hard to achieve the closed-loop control. In case of drilling into the complex formations, the response speed of the driller is often difficult to adapt to changes in working conditions, which is not conducive to the drilling safety. In order to meet the requirements of safety and high automation of rescue drilling construction, the mode of electric control and hydraulic drive is adopted for ZMK5550TZJF50/120 rescue truck-mounted drilling rig. According to the load characteristics of the two main actuators of rotary and feeding systems, a rotary drive system with the characteristics of stepless speed regulation and empty suction control, as well as a feeding drive loop with anti-falling function, were designed. According to the control, monitoring and driving requirements of the system, an electric control system with centralized control and display was developed, with the distributed deployment of bus protocol and the prior cooling of closed loop realized. Besides, seven influential parameters of WOB control were selected, of which the historical data were trained, verified and tested using the BP neural network technology. In this way, the connection weight matrix of drilling parameters and WOB control was obtained, and the adaptive control of WOB was realized. The drilling rig completed the scheduled drilling work in the field industrial test of Meihua Well, with the electro-hydraulic system operating stably and the temperature control system maintaining the oil temperature of the hydraulic system at 40‒60℃ and that of the cooling water of the diesel engine at 70‒90℃. This verifies the good working effect of the closed-loop adaptive control system of temperature. ZMK5550TZJF50/120 truck-mounted drilling rig has preliminarily established the adaptive control mode of WOB. However, due to the diversity and complexity of the formation, it is necessary to continuously enrich the number of samples and improve the system calculation speed, so that the adaptive control system of WOB could be more adaptive to the formation.