In fields such as robotics and wearable exoskeletons, the application of flexible shafts is gradually increasing, and they are being integrated into closed-loop control systems. As a result, the torsional stiffness of flexible shafts has become a critical parameter. Flexible shafts are composed of multiple layers of wound wires. During torsion, the wires experience both tensile deformation and compressive deformation between layers, making modeling and analysis complex. This paper proposes an algorithm for calculating the torsional stiffness of wire-wound flexible shafts. Hertz contact theory is employed to model and analyze the compressive deformation between layers, while the deformation theory of elastic curved rods is used to model and analyze the deformation of wires under force. By establishing boundary conditions, the compressive deformation and curved rod deformation are combined to calculate the torsional stiffness of the flexible shaft. The stiffness of two flexible shafts with different structures was calculated and experimentally tested. The results demonstrate that the proposed algorithm can accurately calculate the stiffness of flexible shafts in linear configurations.

This paper presents the design and optimization of a direct oil cooling system for the stator of a high-power eVTOL (Electric Vertical Takeoff and Landing) propulsion motor. The target motor is a custom-designed outer-rotor permanent magnet synchronous motor (PMSM) with a rated speed of 3200 rpm and a torque of 270 N center dot m. An oil-immersed circulation cooling strategy is adopted, and a dedicated internal oil flow path is designed based on the motor structure. First, the heat losses in the stator windings and core are analyzed and calculated. Then, a three-dimensional fluid-thermal coupled temperature field is simulated using finite element analysis (FEA) at a constant oil flow rate of 10 L/min. Finally, the oil passage geometry is optimized to reduce the maximum winding temperature, minimize pressure losses, and improve the thermal uniformity of the stator winding.

In modern aircraft, the deployment and retraction of thrust reverser cowls are facilitated by multiple linear actuators operating in concert. This configuration, while effective, introduces synchronization challenges due to the simultaneous action of the actuators. To address this issue, flexible steel shafts are incorporated to interconnect the actuators, and a closed-loop control system is implemented to manage their operation. The inherent low stiffness non-linearity of the flexible shafts, combined with the system's multiple inertias, significantly increases the susceptibility of motor speed and load speed to resonance. This paper introduces a prototypical transmission system to elucidate these dynamics. It constructs a dual-inertia servo system model, investigates the principal factors contributing to system resonance, and extends this to a more comprehensive three-inertia model. Through rigorous simulation experiments, the paper validates the developed model, thereby laying a theoretical foundation for the design of more robust control strategies.

The torque overload capability of permanent magnet synchronous motor(PMSM) is very important in transportation applications, which means instantaneous acceleration ability. In the interior PMSMs, the reluctance torque is generated due to the asymmetry of the magnetic circuit, which contributes to the torque overload capacity. In this paper, finite element models(FEMs) of PMSMs with different rotor structures are established to study the torque overload capability. Frozen permeability method is used to analyze the distribution change of rotor permeability under different operating conditions. The torque overload capabilities of different rotor structure are compared. The interior rotor type suitable for overload condition is obtained.

针对直接驱动阀用半浸油式有限转角力矩电机进行设计仿真.通过磁路法快速计算,得到电机的主要尺寸和电磁参数.校核转子腔的厚度满足机械强度要求.根据磁路法得到的参数建立有限转角力矩电机的二维有限元模型,计算其空载气隙磁密、齿槽转矩特性,计算在不同负载时的恒转矩区间范围、输出力矩特性,分析齿槽转矩对输出力矩特性的影响,分析磁路饱和对输出力矩特性的影响.结果表明,转子腔采用导磁材料时,输出力矩大,力矩波动小.

民用飞机轮速传感器是飞机刹车系统的关键设备,用于刹车系统的防滑控制,防止刹车过程中机轮深度打滑和锁死.简要介绍了国外飞机轮速传感器随防滑刹车系统的发展历史,从工作原理和结构形式等方面阐述了变磁阻式、直流式、霍尔式和光电式四种类型的轮速传感器.目前主流民用飞机(包括A320、A330和波音737、波音747、波音777等机型)均采用变磁阻式轮速传感器,其产品形式多样,属于较为成熟的产品;波音787飞机在大型民用客机上采用了霍尔式轮速传感器,其具有体积小重量轻,响应速度快的优势,具有较好的应用前景;公开资料显示,直流式轮速传感器结构复杂、可靠性较低,在协和号飞机上有应用;光电式轮速传感器对振动环境等要求较高,当前技术水平无法满足机轮处恶劣的振动环境,目前尚无装机产品.

The permanent magnet synchronous machine (PMSM)with variable flux hybrid rotor(VFHR) is a hot topic in reliability-critical application like aeronautical servo/drive systems. It is of great benefits to deepen the working mechanism of the permanent magnet synchronous machine with variable flux hybrid rotor for its anti-short capacity by analyzing the transient electromagnetic performance of interturn short faults in PMSM with VFHR. In this paper, the structure of PMSM with VFHR is adopted for analyzing the electromagnetic performance, the interturn short fault in PMSM with VFHR is modelled and transient magnetic analysis of no-load interturn short fault in PMSM with VFHR is carried out based on the model proposed in section II. The demagnetizing field of the interturn short fault is analyzed by comparing the electromagnetic performance before and after the interturn short fault occurs.