Impact Wrench Control Method Using Dual Angle Sensors
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Solution Overview
Problem
Existing control methods for impact wrenches are not suitable for securely fastening steel components using screw connections, as they lack the precision and reliability needed to accurately determine the yield strength and expansion of screws and nuts, leading to potential overexpansion or underexpansion.
Innovation Solution
A dual operating mode control method that uses an impact sensor and angle sensor to detect individual impact angles and relative rotation angles, allowing for precise tightening by setting individual impact setpoint angles and standard angles, ensuring screws are tightened to the correct yield strength without overexpansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single operating mode control method is used for impact wrenches, then the device complexity is reduced and ease of operation is improved, but the manufacturing precision and reliability of screw fastening are insufficient
Solution Approach 1:
The tightening process is segmented into two distinct operating modes: first operating mode for initial tightening with impact angle control, and second operating mode for final tightening with rotation angle control. This segmentation allows each mode to be optimized for its specific function, achieving both ease of operation through automated mode selection and high precision through specialized control algorithms for each stage.
2Reliability
If traditional control methods are used, then the device complexity is low, but the reliability of determining yield strength and preventing overexpansion is insufficient
Solution Approach 1:
The control system continuously monitors impact angles and rotation angles, comparing them against predetermined thresholds. When the impact angle falls below a first threshold in the first operating mode, or when the rotation angle exceeds a second threshold in the second operating mode, the system automatically switches modes or terminates operation. This feedback mechanism ensures reliable determination of yield strength and prevents overexpansion without requiring complex additional hardware.
3Measurement precision
If only impact angle detection is used, then the measurement system is simple, but the precision for determining screw expansion is insufficient
Solution Approach 1:
The system merges two types of measurements: impact angle detection (first measurement value) and rotation angle detection (second measurement value). The impact angle indicates when the screw reaches yield strength, while the rotation angle precisely measures the expansion amount. By combining these two measurement approaches in sequence, the system achieves high measurement precision for both yield strength determination and expansion control without requiring overly complex sensor systems.
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 method enables reliable and precise tightening of screws, tolerant to varying tensions between steel components, preventing overexpansion and ensuring secure fastening, while accounting for user movements and sensor limitations.
Implementation Method 1
detecting the event of an impact of the hammer onto the anvil with the aid of an impact sensor
Implementation Method 2
detecting an angular position of the anvil with the aid of an angle sensor
Implementation Method 3
detecting a rotational movement of the power tool housing during the second operating mode with the aid of a rotational movement sensor
Data Source
AI summary
A control method includes two operating modes carried out in response to a position of a selector switch. The first operating mode provides: carrying out first impacts of the hammer onto the anvil; detecting the event of an impact of the hammer onto the anvil with an impact sensor; detecting an angular position of the anvil with an angle sensor; estimating an individual impact angle of the anvil due to the last detected impact, based on the angular position of the anvil before the last detected impact and the angular position of the anvil after the last detected impact, and comparing the individual impact angle with an individual impact setpoint angle. The first operating mode is ended when the individual impact angle drops below an individual impact setpoint angle. The second operating mode provides: detecting the angular position of the anvil with the angle sensor as the initial position; carrying out second impacts of the hammer onto the anvil; and detecting a relative rotation angle of the anvil with respect to the initial position during the second impacts. The second operating mode is ended when the relative rotation angle exceeds a standard angle.