Model Free Adaptive Control for Thrust Cylinder of Water Well Drilling Rig

Abstract

To solve the problem of poor propulsion velocity tracking performance caused by the load change in the water well drilling rig system, a control method for the thrust cylinder of water well drilling rig based on the data-driven was proposed. The force equation of thrust cylinder with variable load was discretized, and the nonlinear system about output displacement and input current after the discretization was given; Since multiple variables were in the nonlinear system equation and the load changes model was unknown, the model-free adaptive controller based on the data-driven was designed and the pseudo partial lead number method of estimation awas given; A model-free adaptive controller for thrust cylinder of water well drilling rig system was established, and the simulation results were given in the MATLAB/Simulink environment. Research result shows that under the constant load of thrust cylinder in the normal operation, with the time range of 0.05-0.1s , the speed errors of thrust cylinder piston utilizing the model free adaptive control (MFAC) scheme and the PI vector control scheme are 0.05m / s and 0.02m / s , respectively. In the case of thrust cylinder load was changed suddenly, with the time range of 0.4-0.5s , comparison of the momentum error between MFAC and PI control, PI control has 100N overshoot and it can reach the expected value at 0.001s , MFAC can be stable without overshoot at 0.05s . Therefore, the model free adaptive control scheme has better robustness and stability in the control for thrust cylinder of the water well drilling rig, and the proposed method is an effective data-driven control method for suppressing the load disturbance.