Hall Sensor Position Detection Using Segmented Magnet Arrays
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Solution Overview
Problem
Existing robot systems face challenges in accurately determining the reference position of rotatable members, which is crucial for precise motion control and alignment, particularly due to limitations in detecting position changes using single magnets and sensors.
Innovation Solution
A machine with a first member, a second rotatable member, a control device, a drive, and Hall sensors, where three magnets are arranged on a common circular trajectory to enhance signal detection, allowing the control device to determine the reference position by evaluating signal changes from the Hall sensors, and additional magnets for non-contacting sensors to implement limit stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnet and Hall sensor are used for position detection, then the device complexity is low, but the measurement precision of the reference position is insufficient
Solution Approach 1:
The single magnet is segmented into three separate magnets (first, second, and third magnets) arranged on a common circular trajectory. Each magnet interacts with the Hall sensor at different positions, creating distinct signal changes that improve the precision of reference position detection while maintaining a relatively simple overall structure.
Solution Approach 2:
The three magnets are configured with specific local properties: the second magnet (center magnet) is oriented with its magnetic pole facing the Hall sensor in the detection zone, while the first and third magnets have opposite polarity orientation. This local differentiation creates distinct signal characteristics for reference position identification.
2Measurement precision
If multiple Hall sensors are used to detect position changes, then the measurement precision improves, but interference between sensors increases
Solution Approach 1:
The detection function is segmented across three magnets rather than using multiple Hall sensors. Each magnet is positioned to create a distinct signal change pattern, allowing the system to determine reference position through signal evaluation from a single Hall sensor, thereby eliminating inter-sensor interference while maintaining high measurement precision.
3Measurement precision
If three magnets are arranged on a circular trajectory with specific pole orientations, then the detection of reference position is improved, but the device complexity increases
Solution Approach 1:
The three magnets are merged into a unified configuration on a common circular trajectory, where they work together as an integrated position detection system. The magnets are arranged with specific spacing and polarity orientations that create a coordinated signal pattern, improving reference position detection while the common trajectory provides structural simplicity.
Solution Approach 2:
The three magnets are positioned to create periodic signal changes as the rotatable member moves through its range of motion. This periodic arrangement with alternating polarities generates a characteristic signal pattern that enables precise reference position detection through simple signal evaluation, avoiding the need for complex detection electronics.
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
This configuration improves the detection of the reference position by providing distinct signal changes, reduces interference between Hall sensors, and allows for precise adjustment and monitoring of member positions, enhancing the accuracy and reliability of robot operations.
Implementation Method 1
a first Hall sensor that is connected with the control device and is arranged on the first member... the output voltages of which change when approaching the permanent magnet
Data Source
AI summary
The invention relates to a machine comprising a first member, a rotatable second member rotatable relative to the first member relative to an axis, a control device, a drive connected with the control device for moving the two members relative to one another, and a first Hall sensor connected with the control device and arranged on the first member. On the second member, a first, second and third magnet are arranged next to each other on a common circular trajectory such, that during a rotation of the two members relative to one another, the first Hall sensor is located at a specific position in the detection zone of the magnets. The second magnet which is developed as the center magnet is facing towards the first Hall sensor with another magnetic pole than the first and third magnet.