Analysis and decoupling control of a permanent magnet spherical actuator

Area of Science:

• Robotics and Control Systems
• Mechatronics Engineering
• Actuator Design

Background:

• Spherical actuators offer multi-DOF motion but often suffer from coupled control.
• Existing methods struggle to independently control spinning and tilting movements.
• A need exists for a decoupled control strategy for spherical actuators.

Purpose of the Study:

• To present the analysis and decoupling control of a novel spherical actuator.
• To introduce a new actuator design with independent control of motion axes.
• To validate the proposed control strategy through experimental testing.

Main Methods:

• Designed a spherical actuator with a multi-pole permanent magnet rotor and a three-layer coil stator.
• Developed a decoupling control approach assigning specific functions to each coil layer.
• Implemented step control for spinning (middle coils) and computed torque control for tilting (upper/lower coils).

Main Results:

• The proposed actuator design enables three degrees of freedom in a single joint.
• The decoupling control strategy successfully separated spinning and tilting motion control.
• Experimental results validated the effectiveness of the analysis and control approach.

Conclusions:

• The novel spherical actuator design and its decoupling control strategy are effective.
• This approach provides precise and independent control over spinning and tilting motions.
• The findings contribute to advancements in multi-DOF actuator technology for robotics.