Multi-Pole Magnet Sensor for PTZ Camera Positioning
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Solution Overview
Problem
Conventional hall sensor systems for PTZ cameras face challenges in feedback control and accuracy due to the need for close proximity between the sensor and magnet, requiring separate drive modes and resulting in errors and long initialization times, especially when detecting initial positions.
Innovation Solution
A magnetic sensor assembly with a multi-pole magnet configuration and a hall sensor system that allows for real-time angular position recognition without a predefined initialization process, using a processor to estimate initial positions and rotational angles from detected magnetic fields, and maintaining a preset accuracy of 0.1° with quick return to preset positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional hall sensor scheme is used for sensing initial position, then production cost is low and manufacturing is easy, but feedback control is difficult and position information is not recognized unless the magnet passes through sensitive areas
Solution Approach 1:
The rotation member is divided into multiple segments with different numbers of pole pairs (first multi-pole magnet with first number of pole pairs, second multi-pole magnet with second number of pole pairs). This segmentation allows the hall sensor to detect magnetic field patterns from multiple magnet segments, enabling precise position recognition without requiring the magnet to pass through specific sensitive areas, thus resolving the contradiction between easy manufacture and measurement precision.
Solution Approach 2:
The patent transitions from a single-pole magnet configuration to a multi-pole magnet configuration with multiple circumferences (first circumference and second circumference with different numbers of pole pairs). This dimensional change in the magnetic field structure allows the hall sensor to recognize position information from multiple magnetic patterns simultaneously, achieving precise feedback control while maintaining the simplicity of the hall sensor scheme.
2Measurement precision
If the hall sensor and magnet are placed close to each other, then sensing is possible, but separate drive modes are needed and initial position sensing takes time and generates errors according to approach directions
Solution Approach 1:
The multi-pole magnet configuration with multiple circumferences enables the sensor system to perform both initial position sensing and continuous position tracking using the same drive mode. The hall sensor detects magnetic field patterns from multiple magnet segments regardless of the approach direction, eliminating the need for separate drive modes and reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent changes the magnetic field parameters by using multiple pole pairs with different numbers (first number and second number of pole pairs) arranged on different circumferences. This parameter change allows the system to recognize position information from multiple magnetic patterns, making the sensing independent of approach direction and eliminating the need for separate drive modes.
3Ease of manufacture
If a single-pole magnet is used with hall sensor, then production cost is low, but position information is not recognized unless magnet passes through specific areas and feedback control is difficult
Solution Approach 1:
The rotation member is segmented into multiple magnet sections (first multi-pole magnet and second multi-pole magnet with different pole pair counts) instead of using a single-pole magnet. This segmentation creates multiple detectable magnetic patterns that the hall sensor can recognize, enabling continuous position feedback and automated control while maintaining the low-cost hall sensor approach.
Solution Approach 2:
The multi-pole magnet configuration with multiple circumferences provides continuous position information to the hall sensor throughout the rotation cycle. The processor can calculate rotational angle from the detected magnetic field changes, enabling real-time feedback control without requiring the magnet to pass through specific sensitive areas, thus achieving automated feedback control while keeping production costs low.
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
Enables precise real-time recognition of angular positions and quick correction of errors, reducing the need for initialization and improving sensing resolution to 0.1°, allowing for accurate and efficient operation of PTZ cameras.
Implementation Method 1
a hall sensor configured to detect a change of a magnetic field generated from the first multi-pole magnetized magnet and the second multi-pole magnetized magnet
Data Source
AI summary
A magnetic sensor assembly for detecting angular positions of a camera module, includes: a housing; a rotation member configured to rotate together with the camera module; a magnet member that is configured to rotate with the rotation member on at least a portion of the housing, the magnet member includes a first multi-pole magnetized magnet that has a first number of pole pairs alternately disposed along a first circumference on the rotation member, and further includes a second multi-pole magnetized magnet that has a second number of pole pairs alternately disposed along a second circumference on the rotation member; a hall sensor configured to detect a change of magnetic field generated from the first multi-pole magnetized magnet and the second multi-pole magnetized magnet; and a processor configured to estimate an initial position of the rotation member and a rotational angle from the initial position using the detected magnetic field.