Inductive Displacement Transmitter Distance-Independent Detection
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Solution Overview
Problem
Inductive incremental position sensors face challenges in delivering reliable measurement results due to their dependence on the distance between the sensors and the graduation track, leading to inaccurate lateral position detection of a target object.
Innovation Solution
The use of two inductive sensors per sensor unit, arranged at specific distances, generates switching signals based on the difference or ratio of detection signals, ensuring reliable operation independent of the distance, with a threshold-based switching mechanism to prevent bouncing and maintain a direction-independent switching point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inductive sensor is used to detect the graduation track, then the device structure is simple, but the lateral position detection accuracy deteriorates due to distance dependence
Solution Approach 1:
The patent divides a single sensor unit into two separate inductive sensors arranged laterally at a specific distance. Each sensor independently detects the graduation track, and their signals are processed together to eliminate distance dependence. This segmentation allows the system to maintain structural simplicity while achieving accurate lateral position detection independent of the sensor-to-track distance.
2Reliability
If two inductive sensors are used per sensor unit to eliminate distance dependence, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The sensor unit is segmented into two inductive sensors with laterally separated detection points. This segmentation enables the system to obtain two detection signals that, when processed together through subtraction or ratio operations, eliminate the distance-dependent component. The result is improved measurement reliability without requiring complex additional hardware beyond the two sensors and their signal processing circuitry.
Solution Approach 2:
The patent introduces a lateral dimension separation between the two sensors, arranging them at a specific lateral distance from each other. This spatial arrangement in another dimension (lateral direction) creates detection signals with different distance dependencies that can be mathematically combined to cancel out the distance effect, thereby improving reliability while maintaining a relatively simple device structure.
3Measurement precision
If sensors are placed closer to the graduation track to improve detection sensitivity, then detection precision improves, but the switching point becomes more sensitive to distance variations
Solution Approach 1:
By arranging two sensors at a specific lateral distance from each other, the patent creates a spatial configuration where the detection signals contain different distance-dependent components. When these signals are processed together, the system can maintain high detection sensitivity (by placing sensors close to the track) while the combined processing eliminates the switching point's sensitivity to distance variations, thus improving reliability.
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 approach provides precise and reliable detection of the target object's lateral position, independent of distance, enhancing operational safety and reliability, and allowing for simpler distance management in incremental position encoders, resulting in cost savings and expanded application possibilities.
Implementation Method 1
A first sensor unit and a second sensor unit which are at a lateral distance from one another... Each sensor unit having a first inductive sensor and a second inductive sensor... generate detection signals from a conductive area
Data Source
Figure 1~2b
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AI summary
The present invention relates to an inductive incremental displacement transmitter for determining a displacement of a first object relative to a second object comprising at least one graduated track, which has periodically alternating conductive regions and insulating regions, further comprising at least one scanning unit to be attached to the second object for scanning the graduated track by means of a first sensor unit and a second sensor unit, which are disposed at a lateral distance d = n*(p/2)+q from each other, wherein n is an integer, p is the period of the graduated track and 0 < |q| < p/2 is true, and comprising an evaluation unit for determining the displacement based on switching signals supplied by the first sensor unit and the second sensor unit. The inductive incremental displacement transmitter is characterized in that the first sensor unit and the second sensor unit each have a first inductive sensor and a second inductive sensor displaced at a distance thereto, and that the first sensor unit and the second sensor unit fed a switching signal to a conductive region of the graduated track if the difference, or the ratio, of the detection signals generated by said conductive region for the inductive sensors that are part of the respective sensor unit are smaller than a threshold to be defined. The invention further relates to a method for determining the displacement of a first object relative to a second object and to an inductive sensor unit.