The singularity avoidance problem of redundant DOF manipulator was studied.A kinematic model of a 7-DOF manipulator was established based on the screw theory.The singularity of the manipulator was analyzed,and the velocity level inverse kinematics algorithm for singularity avoidance was derived based on the minimum singular value as the singularity optimization index.A path planning experiment for singularity avoidance was conducted based on the velocity level inverse kinematics algorithm.The experimental results show that the inverse kinematics algorithm has good accuracy,which verifies the effectiveness of the singularity avoidance algorithm and lays the foundation for the motion planning of redundant manipulators.
This article firstly models high-frequency and low-frequency signals based on their different characteristics, and then proposes a model and an estimation method for predicting the capacitive shaft voltage of electric vehicle electric drive systems without power supply. Then, based on the shaft voltage model, the influence of two mainstream transmissions is further considered, and an equivalent circuit model of the transmission is established, which can obtain the shaft voltage estimation of the transmission shaft and motor shaft, and realize the shaft voltage modeling and calculation of the overall drive system of electric vehicles. Finally, the paper compares the simulation waveform of the shaft voltage of the transmission shaft and motor shaft of the two transmissions, providing a reference for the selection of transmissions in the electric drive system of electric vehicles.
To improve the reliability of the five-phase permanent magnet synchronous motor system, an open-circuit fault diagnosis method based on the residual current of the mixed logical dynamic model is proposed. According to the continuous current state variables and discrete switching signals of the motor system, a mixed logical dynamic model is established to estimate the real-time motor current. The polarity of the residual current between the model and the actual current is selected as the diagnostic feature. Then, the faulty switch is located by building the fault table. The experiment shows that this method can effectively diagnose single and two open-circuit faults in the system, and the diagnosis time is less than 60% of the current cycle.
为了进一步提高永磁直线同步电机的推力密度和过载能力,将取向硅钢片应用于直线电机的初级铁心.构建了取向硅钢片直线电机的磁网络模型,结合该模型以电磁推力、推力波动和永磁体利用率为优化目标,研究了一种基于灵敏度分析的分层优化方法.针对优化变量采用田口法结合遗传算法进行多目标优化,普通优化变量则采取单参数扫描法进行单目标优化.结果表明,取向硅钢片直线电机的各优化方案,相比初始方案,电磁推力更大的同时推力波动更小,永磁体利用率也得到了提高.
高温超导调相机以响应速度快和占用空间小等优势而在孤岛等特殊电力系统场合被用来替代传统调相机.为保证超导励磁绕组始终工作在超导态,提高高温超导调相机的运行可靠性,需要探究高温超导调相机的阻尼屏蔽结构对超导励磁绕组区域的异步磁场的抑制能力,通过三维有限元仿真对比不同阻尼屏蔽结构在超导电机端部和非端部区域的异步磁场抑制能力,结果表明,铜套阻尼屏蔽结构更加适合应用于高温超导调相机.利用三维仿真计算采用不同阻尼屏蔽结构的高温超导调相机的暂态性能,发现采用铜套阻尼屏蔽结构的高温超导调相机具有更小的次暂态电抗和更大的短路电流.
