Galvanometer Motor Magnetic Position Sensing for Compact Precision
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Solution Overview
Problem
Galvanometer motors have an excessively large volume and accuracy issues due to complex structures and the need for high-precision feedback sensors, which increase costs and susceptibility to temperature drift.
Innovation Solution
A galvanometer motor design featuring a stator with a drive coil and a rotor with radially magnetized magnetic poles, where a magnetic sensor senses the magnetic field to obtain absolute positions, reducing the need for additional feedback sensors and incorporating a calibration coil to correct angular position sensor offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a feedback sensor such as an encoder is mounted in a dedicated cavity to achieve precise positioning performance, then positioning precision is improved, but the motor volume increases and structure becomes complex
Solution Approach 1:
The patent combines the feedback sensor mounting function with the existing stator structure by setting the sensor directly on the stator body, eliminating the need for a separate dedicated cavity. This integration approach maintains precise positioning capability while reducing overall motor volume and structural complexity.
Solution Approach 2:
The patent extracts the feedback sensor from its traditional separate mounting location and repositions it directly on the stator, removing the unnecessary dedicated cavity component. This extraction simplifies the structure while preserving the essential positioning feedback function.
2Measurement precision
If an optical encoder with high precision is configured to detect rotating angle, then measurement precision is improved, but costs increase and contamination tendency occurs
Solution Approach 1:
The patent replaces the optical encoder with a magnetic sensor that detects the magnetic field generated by permanent magnets on the rotor. This substitution eliminates the optical components prone to contamination while maintaining high precision rotating angle detection capability through magnetic field sensing.
Solution Approach 2:
The patent changes the detection parameter from optical signals (prone to contamination) to magnetic field signals (resistant to contamination). By using magnetic sensors to detect magnetic field variations corresponding to rotor position, the system achieves the same measurement precision without the contamination issues inherent in optical systems.
3Ease of manufacture
If an ordinary angular position sensor is used, then costs are reduced, but temperature drift occurs causing position inaccuracy
Solution Approach 1:
The patent implements a feedback mechanism where the magnetic sensor continuously monitors the magnetic field generated by permanent magnets on the rotor, providing real-time position information to the control system. This feedback loop enables temperature compensation and drift correction, maintaining position accuracy despite environmental variations while using cost-effective magnetic sensors.
Solution Approach 2:
The permanent magnets on the rotor generate their own magnetic field that serves as the reference for position detection. This self-generated reference field allows the magnetic sensor to automatically compensate for temperature drift and other environmental factors, eliminating the need for expensive external reference systems while maintaining high measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces the motor's volume, simplifies the structure, and improves accuracy by directly sensing the magnetic field for position determination and calibrating the angular position sensor, addressing the issues of size and precision.
Implementation Method 1
a drive coil mounted inside the housing; a rotor, where the rotor includes a rotating shaft and a galvanometer lens, a pair of radially magnetized magnetic poles are at the middle of the rotating shaft
Implementation Method 2
the sensor board is mounted with a magnetic sensor, and the magnetic sensor is configured to sense a magnetic field signal generated by the pair of magnetic poles, to obtain absolute positions of the rotating shaft
Data Source
AI summary
The present disclosure provides a galvanometer motor, including a stator, a rotor, and a sensor board. The stator includes a housing and a drive coil mounted inside the housing. The rotor includes a rotating shaft and a galvanometer lens. A pair of radially magnetized magnetic poles are at the middle of the rotating shaft, two ends of the rotating shaft are rotatably mounted inside the housing, and one end of the rotating shaft extends outside the housing and is connected to the galvanometer lens. The sensor board is fixed on an inner wall of the housing and is at one end of the housing farther away from the galvanometer lens. The sensor board is mounted with one or more magnetic sensors configured to sense a magnetic field signal generated by the pair of magnetic poles, to obtain absolute positions of the rotating shaft and the galvanometer lens.