Rim-driven thruster (RDT) is frequently subject to external disturbances and speed setpoint changes in complex marine environments. These challenging operating conditions impose stringent requirements on the permanent magnet rim-driven motor (PM-RDM) drive, necessitating both rapid dynamic response and superior disturbance rejection capability. This article proposes an enhanced two-degree-of-freedom (2DOF) control strategy based on an augmented linear active disturbance rejection controller (LADRC) with deviation compensation. An ideal control reference model is introduced to dynamically map the output deviation to the uncompensated disturbances. Moreover, the proposed LADRC can achieve complete decoupling of dynamic response performance and disturbance rejection performance, allowing the controller parameters to be tuned independently without mutual interference. Besides, a decoupled dual adaptive mechanism is integrated based on the tracking error and the observation error, to achieve simultaneous optimization of dynamic response and disturbance rejection performance. Finally, the effectiveness of the proposed LADRC method is validated through the comparative experiments with the conventional LADRC under various working conditions, which confirm the mutual independence of the dynamic response performance and disturbance rejection capability.

Phase locked loop (PLL) is adopted to obtain the position and speed signals, in terms of sensorless control for permanent magnet synchronous motor (PMSM) drives. However, the position estimation accuracy with the traditional PLL deteriorates during fast dynamic process, especially for ship propulsion with frequent speed change and load mutation. To enhance the dynamic response performance, extended state observer (ESO) is embedded into PLL. The PI controller is replaced by ESO, to enhance the tracking capability of dynamic signals. The system characteristics are illustrated and compared. Finally, the feasibility and performance are validated on the PMSM prototype under various operating conditions.

Due to frequent external disturbances occurring in linear motors, especially in long-distance drive systems, traditional proportional-integral (PI) controllers cannot meet the requirements of dynamic performance and robustness capability. The active disturbance rejection controller (ADRC) has been widely adopted for its effectiveness in improving the disturbance immunity of motor drives. Nonetheless, conventional nonlinear ADRC (NLADRC) and linear ADRC (LADRC) have their own advantages, disadvantages, and specific application scopes in the disturbance range. To extend the application range and enhance the dynamic performance and anti-interference capability, a cascaded ADRC (CADRC) is proposed as the speed regulator, which integrates the linear extended state observer (LESO) and the nonlinear extended state observer (NLESO) to estimate the total disturbance. Then the stability and the performance indicators of the proposed CADRC are theoretically analyzed using the Routh-Hurwitz stability criterion and frequency-domain analysis. Finally, the feasibility and effectiveness of the control scheme are verified through simulations and experiments on a prototype of a linear flux-switching permanent magnet (LFSPM) motor.

This paper presents a comparative analysis between a flux concentration Halbach (FCH) and a Halbach consequent-pole (HCP) permanent magnet synchronous machine (PMSM) topology for rim-driven thrusters (RDTs). The performance with respect to mass torque density and permanent magnet utilization is considered. The results demonstrate that the FCH design can operate higher torque density while maintaining comparable permanent magnet utilization to the baseline HCP topology.

This paper presents a direct torque control (DTC) strategy for dual three-phase permanent magnet synchronous motor (DTP-PMSM) based on space vector pulse width modulation (SVPWM), and develops a load torque observer based on the sliding mode observer (SMO). The sliding-mode-based load torque observer (SMLTO) is then integrated into the DTC system to facilitate real-time observation of the motor's load torque. The observed load torque is employed as input compensation for the torque loop of the control system, significantly enhancing the response speed and anti-interference capabilities. The effectiveness of the proposed control strategy is verified through simulations on a 2kW DTP-PMSM platform.

Current research shows that the double-sided linear flux-switching permanent magnet (DLFSPM) motor is suitable for electromagnetic launch systems, in which the armature windings and permanent magnets are set on the long primary stator, whereas the mover is only composed of yokeless iron. Thus, the DLFSPM motor incorporates the merits of high power density and efficiency of the linear permanent magnet synchronous motor and simple and robust structure of linear induction motor. To improve the power factor and decrease the inverter capacity, the segmented power supply control methods of the DLFSPM motor are investigated in this study. First, the structure, electromagnetic parameters, and the segmented power supply method of the DLFSPM motor are explored. Then, the mathematical models and the control strategies of the DLFSPM motor are deduced and proposed. Finally, the simulations and experiments of the DLFSPM motor are conducted to validate the study of segmented power supply method.

Linear flux-switching permanent magnet (LFSPM) motors have drawn extensive concern for rail transit drive systems because permanent magnets and armature windings are all located on the short primary, whereas the long secondary is made up of iron only. Thus, the LFSPM motor with low cost and high efficiency is an excellent choice for urban rail transportation system. However, the installation of linear encoders that are expensive and unreliable along with the long stator will bring about increased costs and reduced reliability. To overcome the shortcomings and fully exert the advantages of LFSPM motors, extended Kalman filter (EKF) is adopted to achieve sensorless control of LFSPMs for its better stability, robustness, and low requirements for working environment in this article. An improving tracking performance can be obtained using EKF considering the end effects of LFSPMs and the presence of noise. Both simulation and experimental results indicate that the motor can run reliably from standstill without position sensors, which is advantageous compared with other sensorless control methods based on electromotive force.

Linear induction motors (LIMs) have been extensively adopted in urban railway transportation given their nonadhesion thrust and simple stator structure. However, these LIMs undergo unfavorable power factor and efficiency considering their copper and eddy losses. Recently, linear flux-switching permanent-magnet motors (LFSPMs) have attracted the attention of researchers due to their high power density, simple structure, easy heat dissipation, high efficiency, and high power factor. However, so far, no quantitative comparison exists between LFSPMs and LIMs of the size 1:1 to prove the feasibility of LFSPMs to be used in railway transit systems. Therefore, a comparative analysis between the two motors is conducted in this paper. First, this paper investigates the LIMs for railway transit using the finite element method (FEM). Second, the LFSPMs for railway transit is designed and optimized. Third, the electromagnetic performance of the two motors is compared and analyzed through the FEM. Finally, a small-sized prototype of the LFSPMs is constructed to validate the FEM results. It is concluded that LFSPMs offer a favorable thrust force, have high efficiency, and high power factor but have large normal force and force ripple. Therefore, applying LFSPM requires a reliable supporting device and a shock absorber.

A new series of linear flux-switching permanent magnet (LFSPM) motors has elicited considerable attention. This series incorporates the merits of the high efficiency of permanent magnet linear motors and the low cost of linear switched reluctance motors for a long-distance drive system. However, the vector control of the LFSPM motor requires an expensive and unreliable linear encoder, which must be as long as the entire railway (or at least the whole linear motor). Such a large encoder will lead to extra costs and will even weaken the benefit of the motor performance. Thus, developing its sensorless control for engineering applications is necessary. Sliding-mode sensorless control has the advantage of strong robustness to parameter variations and external disturbances, as well as high dynamic performance, which is important for long-distance drive systems. The proposed algorithms can extend the minimum operating speed, thereby enabling the motor to work at a lower speed. Both simulation and experimental results are provided for verification.

The working principle and excogitation method of a function configurable manipulator based on Intelligent cylinder is introduced.Intelligent cylinder is an intelligent unit with integrating SCM,sensors and electric-magnetic valve into cylinder.It has been done that establishing mathematical model of the cylinder action for simulation,designing a configured method for requirement of fast and flexible configuration which can make all kinds of functions of intelligent cylinder configuring rapidly to the required function of manipulator.Experiments show that this design method can realize the basic function of the manipulator,and the excogitation method provides a new solution for the multi-function,low-cost and flexibility of the manipulator.

The sensors for measuring water incurved surface radome honeycomb based on the dielectric constant modulation is developed.The dielectric constant indicates the relative capacity of the dielectric to store the electrostatic energy in the electric field.The dielectric constant of water is much larger than the dielectric constant of air and materials of radome, so it can be used to detect the cellular water of radome by the method of the dielectric constant modulation.In order to ensure the test sensitivity, the sensor plates must be closely attached to the measured structure.The shape of radome determines that the plate should be a flexible structure, which can fit the shape of curved surface, the sensor probe is composed of multi plates with a copper bar welding method, and the structure is optimized by using ANSYS software.Through testing the water of honeycomb structure, the experimental results show that the sensor can realize the water detection of honeycomb structure, and has high test sensitivity and repeatability.

With the high power density and the simple structure, complementary and modular linear flux-switching permanent magnet (CMLFSPM) motor is especially suitable for urban rail transit application. A high dynamic performance of the system is significant in transportation system. Compared to the flux oriented control, the Direct Thrust Control (DTC) method has fast torque response and is scarcely influenced by the variation of the motor parameters. However, the direct thrust control of linear flux-switching permanent magnet (LFSPM) is rarely reported. Therefore, a direct thrust control method for the CMLFSPM motor is investigated in this paper. The performance of the proposed control method is demonstrated by simulation results with MATLAB/Simulink software.

Yarn evenness is an important physical parameter of yarn quality. Capacitance sensors provide signals that are used to enable automatic measurement of yarn evenness. These capacitance sensors are expected to be extremely sensitive, highly linear, and electronically homogeneous. But, extremely sensitive sensors can saturate the circuit output under the influence of ambient temperature and humidity. Hence, 3D models of a cylindrical capacitance sensor and parallel plate capacitance sensor are constructed by using finite element analysis. Detection performance of the two types of sensors is compared in terms of sensor sensitivity, linearity, and evenness. We also propose a highly sensitive phase-sensitive detection circuit for the transformer bridge that converts capacitance into a voltage signal. In order to address the problem of premature saturation in the conditioning circuit, this paper proposes a compensation circuit that consists of a programmable capacitor to detect and compensate for output drift in the circuit in real time. Experimental results demonstrate the performance of the proposed capacitance sensor.