Study on load control model and WOB-ROP control laws of drilling robot

At present, the motion characteristics of the drilling robot have not been studied in detail. So, the control of weight on bit (WOB) and rate of penetration (ROP) the drilling robot lacks theoretical basis. The control of WOB and ROP of the drilling robot is either severely delayed or uncontrollable. A motion model with load of the drilling robot was established. Analyzed the motion characteristics of the drilling robot based on the motion model through simulation. On the basis, the univariate control model and multivariable control model of the drilling robot based on the load sensitive principle were established. Analyzed the control response law of the univariate control model and multivariable control model of the drilling robot trough the simulation of control models. Results shows that the main factor determining the motion characteristics of the drilling robot is the distribution of flowrate. Quantitative results show that the multivariable control model achieved a fluctuation attenuation rate exceeding 95% and regulated WOB with a precise sensitivity of approximately 0.7 l/min per bar, proving superior to the univariate model in maintaining stable downhole operations. The univariate control model and multivariable control model of the drilling robot can effectively control WOB and ROP. The proposed univariate control model and multivariable control model of the drilling robot can provide reference and basis for the development of controlled algorithm of drilling robot.