Inductive Sensor Offset Coil for Position Error Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductive sensors face challenges in accurately measuring and compensating for offset errors due to direct coupling between excitation and receiving coils, amplitude mismatches, orthogonality errors, and the need for precise coil alignments, which affect position sensing accuracy and require complex IC designs and manual zero-positioning.
Innovation Solution
The introduction of an offset coil pattern connected to an integrated circuit, which compensates for direct coupling and amplitude mismatches, and allows for electronic zero-position calibration, enabling a single IC design to operate with both two-phase and three-phase systems and minimizing orthogonality errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct coupling between excitation and receiving coils is present, then the sensor structure is simpler, but offset errors increase and measurement precision deteriorates
Solution Approach 1:
An offset coil is introduced as an intermediary element to measure and compensate for the direct coupling between excitation and receiving coils. The offset coil captures the direct coupling signal, which is then used to correct the receiving coil signals, thereby eliminating offset errors while maintaining the simple direct-coupling structure.
Solution Approach 2:
The system implements feedback by using the offset coil measurement to continuously compensate for direct coupling effects. The measured offset signal is fed back to correct the receiving coil signals in real-time, improving measurement precision without requiring complex structural changes.
2Device complexity
If manual zero-positioning is used, then device complexity is reduced, but ease of operation deteriorates and time consumption increases
Solution Approach 1:
The manual mechanical zero-positioning process is replaced with an electronic calibration system. The offset coil enables automatic electronic determination of the zero position through signal processing, eliminating the need for manual mechanical adjustment and improving ease of operation.
Solution Approach 2:
The system performs self-calibration using the offset coil to automatically determine and compensate for zero-position offsets. This self-service capability eliminates the need for external manual intervention during calibration, reducing time consumption and improving ease of operation.
3Manufacturing precision
If separate IC designs are used for two-phase and three-phase systems, then adaptability deteriorates, but manufacturing precision can be maintained
Solution Approach 1:
The offset coil technique provides a universal solution that works for both two-phase and three-phase systems. By using the offset coil to measure and compensate for direct coupling, a single IC design can be used across different phase configurations, improving adaptability while maintaining manufacturing precision.
4Area of stationary object
If receiving coils are placed close to excitation coils, then area is reduced, but direct coupling increases and offset errors worsen
Solution Approach 1:
The offset coil acts as an intermediary that specifically measures the direct coupling effect. By separating the offset measurement function from the position sensing function, the system can tolerate closer placement of receiving coils to excitation coils without sacrificing measurement precision, as the offset is independently measured and compensated.
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 solution enhances the accuracy of position sensing by effectively compensating for offset errors and orthogonality issues, simplifies IC design compatibility, and enables electronic zero-position calibration, improving the reliability and ease of use of inductive sensors.
Implementation Method 1
one or more excitation coils configured to generate one or more electromagnetic fields when electrical current flows through the coil, and one or more receiving coils configured to detect an electrical potential, a voltage, induced in the receiving coil(s) by the currents flowing through the excitation coil
Implementation Method 2
a rotor configured to disturb the amount of electrical potential induced in the receiving coil(s) based on the rotor's position. The rotor is typically attached, directly or indirectly, to the target, such that as a target's position changes and/or as a torque is applied, the rotor's relative position also changes
Data Source
AI summary
Devices, systems, and method for detecting, determining and compensating for offset error arising in inductive position and torque sensors are described. In accordance with at least one embodiment, an offset coil can be configured for use within an inductive sensor and include a first trace and at least one second trace. The first trace and the at least one second trace may be drawn within a stator of an inductive sensor. The first trace and the at least one second trace may be drawn within the stator proximate to a pair of excitation coil connecting leads, drawn on a first plane within the stator, and on at least one plane substantially parallel to the first plane such that wherein an excitation coil flowing through the pair of excitation coil connecting leads induces an offset coil signal in the first trace and at least second trace.