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.