Magnetoresistive Sensor Assembly for 3D Position Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor arrangements for coordinate measuring machines require a large number of magnets and Hall elements, making them bulky and difficult to implement in a compact form, especially for 3D position determination, and are susceptible to external disturbances like the earth's magnetic field, which limits measurement accuracy.
Innovation Solution
A sensor arrangement using at least four magnetic field sensors forming pairs to generate common signals for orthogonal measurement axes, with the sensors being insensitive to magnetic field strength and primarily responsive to direction, allowing for precise position determination and compact design, including the use of magnetoresistive sensors like AMR or GMR sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall elements and magnets are used for position determination in multiple measuring axes, then position determination capability is improved, but device size and complexity increase due to requiring many individual components
Solution Approach 1:
The patent combines multiple measurement functions into a single integrated sensor unit. Multiple magnetoresistive sensors are arranged on one side to detect magnetic field vectors from multiple magnets, enabling determination of position along multiple measuring axes simultaneously. This merging approach replaces the conventional need for separate sensor pairs for each axis, reducing overall device complexity while maintaining multi-axis position determination capability.
Solution Approach 2:
Each magnetoresistive sensor is designed to detect magnetic field vectors that contain information about position along multiple measuring axes. By analyzing the combined output signals from multiple sensors and magnets, the system determines position in three-dimensional space along x, y, and z axes using a single sensor assembly, giving the system universal position determination capability across multiple axes.
2Measurement precision
If magnets are arranged far apart for good decoupling between sensor pairs, then measurement selectivity is improved, but compact implementation becomes difficult
Solution Approach 1:
The patent replaces the mechanical arrangement of multiple separate sensor pairs with a magnetic field-based detection system. Multiple magnetoresistive sensors detect the combined magnetic field vectors from multiple magnets, and electronic signal processing distinguishes the individual position components. This substitution allows magnets to be arranged closer together while maintaining measurement selectivity through mathematical decoupling rather than physical separation.
Solution Approach 2:
The system changes from measuring magnetic field magnitude (as with Hall elements) to measuring magnetic field vector direction and components. By detecting the vector components along different axes and using signal processing to separate the contributions from different magnets, the system achieves good decoupling and selectivity even when magnets are arranged in a compact configuration.
3Measurement precision
If Hall elements are used that respond to magnetic field strength changes, then sensitivity is improved, but susceptibility to external disturbances like earth's magnetic field increases
Solution Approach 1:
The patent uses magnetoresistive sensors that detect magnetic field vector direction rather than magnitude. This approach converts the problem of external magnetic disturbances into a solvable issue by measuring the directional components of the total magnetic field. Through signal processing that analyzes the vector components from multiple sensors, the system can distinguish the position-dependent magnetic field components from external disturbances like the earth's magnetic field, effectively filtering out harmful influences while maintaining sensitivity.
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 3D position determination with high measurement accuracy, resistance to external disturbances, and cost-effective implementation by optimizing sensor geometry and signal processing, allowing for all six degrees of freedom to be determined with a single integrated sensor assembly.
Implementation Method 1
A sensor arrangement uses at least four magnetic field sensors forming pairs to generate common signals for orthogonal measurement axes, with the sensors being insensitive to magnetic field strength and primarily responsive to direction, allowing for precise position determination and compact design, including the use of magnetoresistive sensors like AMR or GMR sensors.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a sensor assembly for determining a spatial position of a first part (114) relative to a second part (112), comprising at least one magnet (74), which is arranged on the first part (114). The magnet (74) generates a magnetic field which extends to the second part (112). The sensor assembly further includes a first and a second magnetic field sensor (80, 82), which are arranged at a spatial distance (84) relative to one another on the second part (114). The at least one magnet (74) is positioned in the spatial distance between the magnetic field sensors (80, 82). The magnetic field sensors (80, 82) generate a respective output signal depending on the magnetic field. The output signals of the two second magnetic field sensors (80, 82) are combined to form a common sensor signal, which is dependent on the spatial position of the first part (114) relative to the second part (112) along a defined measuring axis (96). The defined measuring axis (96) is located transversely to the spatial distance, and the output signals of the first and second magnetic field sensors (80, 82) essentially represent a magnetic field direction at the location of the respective second magnetic field sensor (80, 82).