Semi-active floating drilling platform crown block heave compensation device

The invention discloses a semi-active floating drilling platform crown block heave compensation device which comprises a crown block frame, a floating crown block, a transmission mechanism, a pneumatic compensating cylinder, high-pressure gas cylinder groups and the like. The transmission mechanism can be combined by the aid of linear motor movers and stators and can be also combined by the aid of gears and racks, the transmission mechanism drives the floating crown block to vertically motion and provides active heave compensation force of the crown block, the pneumatic compensating cylinder is fixed on the crown block frame, pushes the crown block to vertically motion and provides passive compensation force of the crown block, the high-pressure gas cylinder groups comprise a plurality of high-pressure gas cylinders and provide needed energy for working of the pneumatic compensating cylinder by compressing gas, and semi-active crown block heave compensation is achieved under the collective actions of the tran