Screwdriver Torque Quality Control Under Transmission Noise
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Solution Overview
Problem
Current screwing tools in industrial settings face challenges in accurately measuring torque due to noise from transmission elements, leading to poor precision and potential tool failure, requiring frequent maintenance and production interruptions for quality control.
Innovation Solution
A method to analyze torque data during screwing operations to identify disturbances and deviations from the objective, generating a warning signal if parameters exceed thresholds, allowing for real-time monitoring and maintenance without production halts, by processing torque data into tables representing true characteristics and disturbances, and computing dispersion and deviation values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If torque measurement is performed using transmission elements (gears, epicyclic gear trains), then torque amplification is achieved, but measurement precision deteriorates due to noise from these transmission elements
Solution Approach 1:
The patent segments the torque measurement function from the torque transmission function. A separate measurement path is created using a measurement wheel and encoder that directly measures the torque applied to the screw without being affected by the noise from the epicyclic gear trains and other transmission elements. This allows the transmission elements to perform their torque amplification function while the measurement system independently captures accurate torque data.
Solution Approach 2:
The patent introduces an intermediary measurement system consisting of a measurement wheel, encoder, and signal processing unit that acts as a mediator between the actual torque application and the measurement process. This intermediary system captures the true torque signal without being contaminated by the noise from transmission elements, thereby resolving the contradiction between torque amplification and measurement precision.
2Measurement precision
If regular quality control checks are performed on test beds, then tool precision is verified, but production efficiency decreases due to production stoppages and tool relocation
Solution Approach 1:
The patent implements a self-service quality control system where the screwdriver performs its own precision verification during normal production operations. The measurement system continuously monitors torque parameters and compares them against reference values, automatically detecting precision degradation without requiring external test beds or production stoppages. This allows the tool to self-diagnose its condition while maintaining production flow.
Solution Approach 2:
The patent enables continuous quality control by performing precision verification during actual screwing operations rather than during separate test bed checks. The measurement and analysis process runs continuously alongside production work, ensuring that precision monitoring does not interrupt the useful action of manufacturing, thereby maintaining both quality verification and production efficiency.
3Reliability
If maintenance is performed based on empirical usage counters, then preventive maintenance is scheduled, but actual tool state is not accurately reflected leading to premature or delayed maintenance
Solution Approach 1:
The patent implements a feedback-based maintenance system where actual torque measurement data is continuously monitored and compared against reference values. When deviations exceed predetermined thresholds, the system provides feedback indicating actual tool degradation. This real-time feedback replaces empirical usage-based scheduling with condition-based maintenance, ensuring maintenance is performed based on actual tool state rather than estimated usage, thereby optimizing maintenance timing and avoiding both premature and delayed maintenance.
Data Source
AI summary
A method for controlling a level of screwing quality of a screwdriver relative to a predetermined screwing objective. The method includes: obtaining, at a predetermined angular frequency, a series of doublets representative of a rise in screwing torque for at least one screw, constituting a first table of values, each doublet including an angle value and a torque value; determining, from the first table, a second table of values presenting the torque as a function of the angle and being representative of the true characteristic of the at least one screw; determining a third table of values, presenting the torque as a function of the angle and being representative of disturbances induced by the screwdriver during the rise in torque, from the first and second tables; analysis of the third table, delivering information representative of a dispersion and/or a deviation relative to the screwing objective, resulting from the screwdriver-induced disturbances.