| Rotary steering drilling stable platform works under the ground. The condition of downhole is complicated and there are many uncertain factors in the process of drilling. It is difficult to obtain accurate mathematical model,and achieve the ideal control result by traditional method. In order to further improve the control quality of stabilized platform system, and ensure that drilling tools guide deflection under the requirement of high precision. This paper realizes the control of the rotary steering drilling stabilized platform system based on the generalized predictive control theory.In this paper, stable platform generalized object model is obtained based on the structure and working principle of the rotary steering drilling stable platform; because of the relative motion between the upper and lower plate valve, the changing pulsating torque is studied; the plate valve friction model of the stabilized platform control system is established.The basic algorithm of generalized predictive control is illustrated, and the principle of selecting the controller parameters is given. The stable generalized predictive control simulation software is established with MATLAB GUI, which has the advantages of simple operation, strong interactivity and visualization. This software can carry out simulation research of the stable platform, meanwhile the predictive controller parameters is optimized.In this paper, a new algorithm of stair-like generalized predictive is formed, which reduce the computation of matrix. This algorithm is applied to the tool face angle control, and it is compared with fuzzy PID and model predictive control. Simulation results show that the algorithm can effectively inhibit friction, has better robustness, and has good dynamic performance and steady-state precision, so that the control performance is greatly improved. |
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