US Patent 10215010 Anti-whirl systems and methods

Systems and methods for reducing or eliminating whirl are described. The system includes a controller and a drive system. The controller is configured to collect downhole information, determine a natural frequency of a drill string in the lateral motion, determine correlative relationships, model a forward whirl region, generate a control algorithm, determine a top drive supervisory setpoint, and provide operational control signals. The drive system is configured to receive the one or more operational control signals and limit the top drive RPM.