Capacitance-Based Movable Tool Detection for Human Tissue Sensing
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Solution Overview
Problem
Existing methods for detecting substances, particularly human tissue, near movable tools like saw blades are unreliable, sensitive to false positives, and complex, often requiring additional sensors such as cameras or infrared systems.
Innovation Solution
A method that detects periodic changes in capacitance caused by geometric changes of the tool as it moves, using the tool and a counter electrode to form a capacitance, which is sensitive to dielectric properties of substances, allowing for reliable and sensitive detection without external sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors such as cameras or infrared sensors are used for detection, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the detection function with the existing machine tool structure by using the tool itself as one electrode of a capacitor. The capacitance detection system is integrated into the control unit of the machine tool, eliminating the need for separate external sensors and reducing overall system complexity while maintaining detection capability
Solution Approach 2:
The machine tool structure serves multiple functions: it performs the cutting operation and simultaneously acts as an electrode for capacitance-based detection. The control unit processes both operational control signals and detection signals, making the system multi-functional without requiring additional dedicated components
2Measurement precision
If electromagnetic field changes are detected to identify substances, then detection sensitivity is improved, but reliability decreases due to false positives
Solution Approach 1:
The patent changes the detection parameter from electromagnetic field changes to capacitance changes. By measuring capacitance between the tool (electrode) and counter electrode, the system detects substances based on their dielectric properties, which provides more reliable differentiation between materials and reduces false positives while maintaining sensitivity
Solution Approach 2:
The detection system uses the specific geometric properties and movement of the local tool region to create a periodic capacitance signal when substance is detected. This localized periodic detection approach improves reliability by providing characteristic signal patterns that distinguish true detections from noise
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 high reliability and sensitivity in detecting substances near movable tools, effectively identifying dangerous situations and defects like nails in wood, while being insensitive to external influences like dust, and allows for simple integration into existing machine tools.
Implementation Method 1
A capacitance is formed by a tool (2) forming a first electrode and a counter electrode (4) electrically insulated from the tool (2)
Implementation Method 2
The capacitance depends on the electrode surfaces, the distance between the electrodes, and a substance with certain electrical properties, in particular certain dielectric properties, located in the electric field between the electrodes
Data Source
Figure 1
Figure 2a~2f
Figure 3a~3f
AI summary
Method for detecting a substance (1), preferably human tissue, in the vicinity of a movable tool (2), the substance (1) to be detected differing in its electrical properties from a material (3 ) distinguishes, and wherein in the method a change in a capacitance (5) formed by the tool (2) and a counter-electrode (4) electrically insulated from the tool (2) is detected, a periodic change in the capacitance (5) being detected , this change being caused by the fact that the substance (1) is arranged in an area (B) relative to the tool (2) and when the tool (2) moves, a geometric property of the tool (2) changes in this area ( B) changes periodically.