Permanent magnet synchronous motor (PMSM) has been widely employed in the continuous-wave pulse generator and exhibits advanced performance. However, its applications are constrained to some extent, because of the alternating load shocks and measurement resolution, etc. To cope with these issues, a double degree-of-freedom (DOF) control strategy that combines the extended Kalman filter (EKF) and adaptive linear active disturbance rejection control (LADRC) is proposed to realize fast dynamic response and strong anti-interference capability. The EKF is established according to the PMSM motion model to filter measurement noise and generate external disturbance estimations in a timely manner and reduce the observed burden of adaptive LADRC. The LADRC characteristics are analyzed to highlight conflicts between dynamic response and noise suppression under different observer and system bandwidths. Then, adaptive bandwidth laws are constructed. Finally, the simulation and experimental results are achieved to verify the effectiveness of the proposed strategy for the PMSM control system. It is believed that the striking advantages of such a method render it very suitable and powerful for the speed control of a continuous-wave pulse generator.

In the dynamic point-the-bit rotary steerable system (DPRSS), a high dynamic stiffness toolface control method is desired to ensure the stabilized platform traces the directional command accurately and quickly. A three-loop compound toolface control method using the Model-based Active Disturbance Rejection Control (MADRC) algorithm is presented, and a load torque estimator and an outer housing speed estimator are designed based on system model to obtain the external disturbances. The proposed toolface control method was verified by numerical simulation and DPRSS prototype testing, and its speed loop frequency responses are analyzed. The results reveal that this method is effective in disturbance rejection and robust against parameter uncertainties, and the MADRC shows better performance compared with the conventional ADRC and the proportional-integral (PI) controller. The proposed method has the potential to be used in harsh drilling conditions.

In this paper, the sensor fault detection (FD) problem is investigated for the dynamic point-the-bit rotary steerable system (DPRSS), which is known as state-of-the-art oil drilling equipment. Firstly, the DPRSS dynamic is modelled as a linear system with drilling disturbances, which consists of model perturbations, measurement disturbances, and unknown inputs. Secondly, the finite-frequency $H_{-}/H_{\infty }$ unknown input observer is proposed to generate the residual, which is sensitive to sensor faults and robust against drilling disturbances. Subsequently, considering model perturbations and measurement disturbances, the zonotope-based residual evaluation method is presented, and the FD decision-making logic is designed based on the calculated residual bounds. Finally, numerical simulations and prototype experiments are provided to illustrate the effectiveness of the proposed sensor FD mechanism.