An orientation measurement method based on Hall-effect sensors for permanent magnet spherical actuators with 3D...

Area of Science:

• Robotics and Control Systems
• Electromagnetism and Magnetic Sensors
• Mechanical Engineering

Background:

• Conventional orientation measurement methods for permanent magnet (PM) spherical actuators often involve physical contact, leading to friction torque and added inertia.
• Accurate real-time orientation data is crucial for precise motion control of these actuators.

Purpose of the Study:

• To propose and validate a non-contact orientation measurement method for PM spherical actuators using Hall-effect sensors.
• To develop an accurate analytical model for magnetic field distribution in a 3D magnet array.
• To improve the precision and reliability of orientation sensing in spherical actuators.

Main Methods:

• Utilizing an array of Hall-effect sensors positioned around the rotor to detect magnetic flux density.
• Developing a curved surface fitting method based on exponential approximation for 3D magnetic field modeling.
• Validating the proposed method through experimental measurements on a research prototype.

Main Results:

• The proposed Hall-effect sensor method accurately measures rotor orientation without contact.
• The novel 3D magnet array and improved modeling enhance measurement precision.
• Experimental results confirm the accuracy of the analytical equations relating magnetic flux density to orientation.

Conclusions:

• The non-contact Hall-effect sensor method offers a precise and reliable solution for orientation measurement in PM spherical actuators.
• The developed analytical model improves magnetic field distribution accuracy.
• This technique is suitable for real-time motion control applications, enhancing actuator performance.