Nonlinear dynamics model of servo platform for steering drilling tool

The function of the servo platform is to control the borehole's deviation and orientation by using an automatic control method to drive the platform suspending at a special angle. However, it is not an easy job to control this cylindrical and rotating platform at a particular angle under the complex downhole environment. The key to solve this problem is to establish a suitable nonlinear model. Based on the structure analysis of the platform, a general law of dynamics equation is obtained by analyzing friction, drilling fluid shock, eccentric action, etc. A hydraulic driving torque test has been done, which indicates that the dynamics analysis is reasonable. The model lies the foundation for the research of platform's control method and the improvement of mechanical design.