Yusuke Nishiura

Optimization of stator pole arrangement for 3-DOF spherical actuator using genetic algorithm

The development of multi degree-of-freedom actuating systems is required in robotics and industrial machinery fields. In general, however, the actuating system with several degrees of freedom is composed of single degree-of-freedom motors, which results in large, heavy and complicated structures. Therefore, multi-degree-of-freedom actuators are expected to become a key technology to solve these problems and many types of actuators have been studied [1]-[3]. There remain, however, some problems in terms of the torque density, control method, and sensing systems. Under the circumstances, we are studying on an outer rotor 3-DOF spherical actuator with a multi-poles stator and a multi-pole pair permanent magnets rotor. In this paper, to increase the torque density, stator pole arrangement is optimized using Genetic Algorithm (GA) and the effectiveness of the optimization is confirmed.

Experimental Evaluation of the Static Characteristics of Multi-Degree-of-Freedom Spherical Actuators

Multi-degree-of-freedom (multi-DOF) actuators have been developed for the fields of robotics and industrial machinery.

3-DOF outer rotor electromagnetic spherical actuator

Conventionally, many single-degree-of-freedom actuators were used to realize devices with multi degrees of freedom. However, this makes the structure larger, heavier and more complicated due to the large number of actuators. To remove these drawbacks, the development of a spherical actuator with multi degrees of freedom is necessary, and various spherical actuators have been developed [1], including our own [2]. However some problems such as low torque, large size and narrow rotation range remain. To solve these problems, the employment of an outer rotor structure is one of the solutions. In this paper, we propose a new 3-DOF outer rotor spherical actuator and its control methods. The basic construction and operating principle are described. The static torque characteristics and dynamic characteristics are computed employing 3-D FEM, in which two types of control methods are taken into account and finally verify it by the measurement on a prototype.