Semi-active drilling drawworks heave compensation system

In order to simplify the structure of the ocean drilling heave compensation system and reduce the energy consumption of active drawworks heave compensation system, a new type of semi-active drawworks heave compensation system was designed through structure design, system modeling and internal model PID robust displacement controller design. Then the feasibility of the system was verified by non-linear time domain simulation and experimental study. The structure design realizes decoupling control of heave compensation and automatic bit feed, reduces energy consumption of the system. The system is simplified to build simulation model by lumped mass method and energy conservation principle. The double control scheme of hook displacement closed loop in the outer loop and motor speed closed loop in the inner loop is put forward, the internal model PID robust displacement controller of outer loop is designed. The steady-state deviation of internal model control is zero when the model is matching or mismatching. The dynamic performance and resisting disturbance capacity of the internal model control is better when the filter time constant is smaller. The compensation rate is above 90% by simulation and experimental research results, the compensation effect is good and the system is feasible. Key words: drilling platform, drawworks, heave compensation, semi-active, system desig