Movable Tool Capacitance Sensing for Tissue and Nail Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting substances near movable tools, such as circular saws, lack reliability and sensitivity in differentiating between workpieces and human tissue, leading to potential false positives and complications in machine tool design.
Innovation Solution
A method that detects periodic changes in capacitance caused by the geometrical properties of the tool as it moves, using a capacitance system formed between the tool and a counterpart electrode, allowing for reliable and sensitive detection of substances in the vicinity, including human tissue, without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sensors like camera systems, lasers or infrared sensors are used for detection, then the sensitivity and reliability of detecting substances near the tool is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the detection function with the existing tool structure by forming a capacitance system between the tool itself and a counterpart electrode. This integration eliminates the need for separate additional sensors while maintaining detection capability, thereby reducing device complexity and cost while preserving reliability
Solution Approach 2:
The tool serves dual functions: it performs its primary cutting function while simultaneously acting as one electrode of the capacitance detection system. This multi-functionality reduces the need for dedicated detection components, simplifying the overall system structure
2Measurement precision
If additional sensors like camera systems, lasers or infrared sensors are used for detection, then the sensitivity in differentiating between workpiece and human tissue is improved, but the device complexity and cost increase
Solution Approach 1:
The patent utilizes changes in dielectric properties (permittivity) of different substances as the detection parameter. By measuring capacitance variations caused by different dielectric constants of workpiece materials versus human tissue, the system achieves accurate substance differentiation using the simple capacitance measurement principle rather than complex sensor systems
3Device complexity
If the detection system uses the tool itself as an electrode, then the device complexity is reduced, but the measurement precision must be maintained
Solution Approach 1:
The patent employs dynamic measurement by detecting periodic changes in capacitance that occur during tool movement. The periodic variation in capacitance signal, caused by the tool's motion relative to the substance, provides characteristic patterns that enable precise detection and differentiation of substances even when using the tool itself as the electrode
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 enhances the reliability and sensitivity of detecting substances near movable tools, preventing accidental contact and detecting foreign bodies like nails, while being insensitive to external influences like dust, and allows for simpler and less expensive integration into machine tools.
Implementation Method 1
The capacitance depends on the electrode surface areas, the spacing of the electrodes and a substance in the electric field between the electrodes (or in an edge region of the electrodes), of given electrical properties, in particular certain dielectric properties
Implementation Method 2
different dielectrics involving different degrees of permittivity (dielectric constants) can influence the capacitance. Thus for example the substance to be detected, for example human tissue in the form of part of the body of a user of the movable tool, can differ from the permittivity of the material to be processed
Data Source
AI summary
A method is provided for detecting a substance, preferably human tissue, in the vicinity of a mobile tool, wherein the substance to be detected has different electrical characteristics from a material that can be processed by the mobile tool. In the method, a change is detected in a capacitance formed by the tool and a counter electrode that is electrically insulated from the tool. A periodic change in the capacitance is detected and the change is produced by the presence of the substance in a region in relation to the tool and by a periodic change in a geometrical characteristic of the tool in this region as the tool moves.