Improvements of Performance of Multi-DOF Spherical Motor by Double Air-gap Feature

Abstract

-As the need of electric motor is increased rapidly throughout our society, the various application fields are created and the service market called robot gets expanded as well as the existing industrial market. Out of those, the joint systems such as humanoid that is servo actuator for position control or all fields which require multi-degree of freedom (multi-DOF) require the development of innovative actuator. It is multi-DOF spherical motor that can replace the existing system in multi-DOF operating system. But, multi-DOF spherical motor that has been researched up to date is at the stage which is insufficient in performance or mechanical practicality yet. Thus, first of all the research results and limitation of the previously-researched guide frame-type spherical motors were analyzed and then the feature of double air-gap spherical motor which was devised to complement that was studied. The double air-gap multi-DOF spherical motor is very suitable spherical motor for system applying which requires the multi-DOF operation due to its simple structure that does not require other guide frame as well as performance improvement due to its special shape which has two air-gaps. So, the validity of the study was verified by designing and producing it with 3D-FEM through the exclusive jig for multi-DOF spherical motor.

Adaptive Sliding‐Mode Control for Permanent Magnet Spherical Actuator Based on Trajectory Re‐Planning

“…Compared to traditional multi-degree-of-freedom (DOF) device, a permanent magnet spherical actuator (PMSA), which has the advantages of compact structure, relatively large range of motion, and rapid dynamic response, can be used in various applications, e.g., modern aerospace [1], robotics [2,3], and spherical wheel [4].…”

Robust Adaptive Sliding-Mode Control of a Permanent Magnetic Spherical Actuator With Delay Compensation

“…A permanent magnet spherical actuator (PMSA) has the advantages of compact structure, relatively large range of motion and rapid dynamic response. Given that the PMSA can provide three degree-of-freedom movement in one joint, this system is used in various applications in modern aerospace, robotics and other fields [1][2][3].…”

A Novel Tiered Type Permanent Magnet Spherical Motor and Its Rotor Orientation Measurement Principle

“…The corresponding torque density, which is defined as the torque per unit volume of rotor sphere, is about 1.03 N•m/L. In [11], an iron shell is employed in the PM spherical motor to increase the torque ability and a higher torque density of about 1.28 N•m/L is achieved. Despite that the use of iron shell can enhance the torque ability effectively [12], the torque density is still too low due to the large air gap caused by use of air-cored coils.…”