Analysis and decoupling control of a permanent magnet spherical actuator

Abstract

This paper presents the analysis and decoupling control of a spherical actuator, which is capable of performing three degree-of-freedom motion in one joint. The proposed actuator consists of a rotor with multiple PM (Permanent Magnet) poles in a circle and a stator with circumferential coils in three layers. Based on this actuator design, a decoupling control approach is developed. Unlike existing control methods that each coil is responsible for both the spinning and tilting motion, the proposed control strategy specifies the function of each coil. Specifically, the spinning motion is governed by the middle layer coils with a step control approach; while the tilting motion is regulated by upper and lower coils with a computed torque control method. Experiments have been conducted on the prototype to verify the validity of the design procedure, and the experimental results demonstrate the effectiveness of the analysis and control strategy.

Design and Control of a Three-Coil Permanent Magnet Spherical Motor

“…However, the first studies on the spherical movement of the axis of an electric motor date back to the 1950s with the works of Williams et al [9][10][11] and Haeussermann et al [12,13]. Since then, several interesting proposals have emerged [14][15][16][17], but the published designs are difficult to reproduce to verify the achieved results [18][19][20][21][22][23].…”

“…For this purpose, among the 100 independent runs using the training set with 2800 samples, the best performing MLP (2,25,20,3) network was selected and the weights and biases determined for this network in the experiments were applied to the real spherical motor constructed…”

Continuous 3D printing from one single droplet

“…Additive manufacturing or 3D printing rapidly turns computer-aided designs into complex 3D objects without the use of the molds, dies or lithographic masks that are needed for conventional manufacturing 1 , 2 . 3D printing based on photocuring, which allows solidification of a 3D model at the curing interface 3 – 6 , has become a promising technique with a variety of applications, such as in biomimetic investigations 7 – 11 , microfluidics 12 – 14 , sensors, and shape-morphing systems 15 – 19 . Although effective in constructing fine structures, compared with fused deposition modeling (FDM), the existing digital light processing (DLP), stereolithography (SLA) printing and volumetric additive manufacture technologies have low wet material utilization efficiency (the weight ratio of the just printed structure to the initial liquid resin) and net material utilization efficiency (the weight ratio of the acquired dry structure to the initial liquid resin).…”