High-speed and high-precision position servo system of permanent magnet synchronous motor (PMSM) is the key part of the research and development of the manipulator's joint. The active disturbance rejection control (ADRC) is one of the commonly used methods in the position servo system, which has the advantages of fast speed and easy physical realization. However, the existing ADRC mostly adopts the three-loop structure of position-speed-current, which has some problems such as slow positioning response, poor positioning accuracy, and poor load adaptability caused by difficult parameter tuning. Therefore, a new load adaptive two-loop drive system based on an improved position-speed integrated ADRC with a parameter fuzzy self-tuning method is proposed. In order to verify the effectiveness of the scheme, a test platform for a Selective Compliance Assembly Robot Arm (SCARA) is established. The results show that the drive system designed by the proposed method has high positioning accuracy, fast positioning response, and adaptability to load changes.

Improving the positioning response is one of the key goals for permanent magnet synchronous motor position servo systems. The sliding mode variable structure controller (SMVSC) is an effective method due to the advantages of strong robustness, fast response, and easy practical implementation. However, the existing SMVSCs have difficulties in optimizing the position tracking response speed and chattering performance at the same time. This article proposes an improved position speed integrated SMVSC (ISMVSC) with a new variable exponential reaching law based on position error and a saturation function, and a speed-limiting method using speed error and trajectory planning. The general design principle is given and various tests are carried out to verify the effectiveness of the proposed method. The experimental results show that compared with traditional methods, the ISMVSC can improve the positioning response speed and reduce chattering problems at the same time; it also exhibits a stronger transient speed-limiting ability. All these advantages make the proposed controller a superior method to achieve high-response positioning control of the servo system that performs point-to-point motion.

The double-sided tubular linear machine (DSTLM) has a more compact structure than general single-sided motors, resulting in a higher power density, typically at the cost of a higher cogging force. To reduce this aspect and make it more suitable for applications in wave energy conversion systems or elevator driver systems, a new tooth-cutting topology is proposed in this article. The Schwarz–Christoffel mapping method is used to model and analyze the magnetic field and cogging force of the DSTLM. Based on the analytical model and the relationships between the cutting dimensions and the force performances, optimization is carried out by using a differential evolution algorithm. The optimization and the experiment results show that the proposed tooth-cutting topology can effectively reduce the cogging force at the small cost of weakening average thrust.

In this paper we have investigated the entanglement evolutions between a two-level atom and a single-mode field as well as two two-level atoms in different W-like initial states in T-C model. It is shown that the evolutions of the formation entanglement between them are periodical, and the periods of the entanglement evolutions are different according to the difference of the initial states.The so-called sudden death of entanglement occures between two atoms as the initial states is some W-like initial state.

The performance of the motor drive system is responsible for the yarn feeding quality of the weft accumulator. The existing motor drive systems have problems such as slow start–stop and poor dynamic response performance, resulting in slow yarn tracking speed and low precision of the weft accumulator. This article proposes a new self-balancing yarn number control method based on a novel sensorless permanent magnet synchronous motor (PMSM) speed drive system. The novel sensorless PMSM speed drive system is constructed to improve the dynamic response performance of PMSM by integrating an improved sliding mode observer, a simplified initial position detection method, and a new hybrid control method. The self-balancing yarn number closed-loop control method is proposed based on a pseudoderivative feedback controller to improve the response speed and accuracy of yarn feeding. The general design principle is given, and various tests are carried out. The results show that the proposed drive system has characteristics of a fast start–stop and high dynamic response, which can meet the high-response and high-precision yarn feeding requirements of the weft accumulator.