Design of a new type of spherical voice coil actuator

• Design and optimization of a new type of spherical voice coil actuator.
• Principle of the proposed actuator is based on Lorentz force.
• A large tilt angle, a high tilt torque, and a uniform and decoupled torque constant by each coil with a compact diameter of 100 mm.
• One pair of coils is circular, and the other is rectangular.

In this article, we describe the design of and an experiment with a new type of spherical voice coil actuator. The designed actuator has a large tilt angle of ±40°, high tilt torque, and a uniform and decoupled torque constant for each coil within a compact diameter of 100 mm. The designed actuator is composed of a rotor, a gimbal guide mechanism, and a stator. In order to decouple the tilt torque generated by each coil, the rotor has two pairs of coils. One pair of coils is circular, and the other is rectangular. For that reason, each axis of the gimbal guide mechanism coincides with each axis of the tilt torque generated by each corresponding pair of coils. In addition, because the principle of the proposed actuator is based on the Lorentz force, the tilt torque generated by each coil is directly proportional to the driving current. Therefore, the proposed actuator is easy to control. We carried out optimization of the proposed actuator to maximize the tilt torque with a limited size. To verify the results of the optimal design process of the actuator, an FEM simulation was carried out. We realized and tested the designed actuator to verify the torque performance. The realized actuator has an X and Y′-axis tilt torque constant of 0.35 Nm/A.