Miter Saw Angle Display Calibration via Feedback
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Solution Overview
Problem
Conventional miter saws experience machining and assembly errors, leading to inaccuracies in displaying the rotation and tilting angles of the turntable and circular saw blade, which can result in user perceptions of the tool being defective.
Innovation Solution
A miter saw design incorporating a rotation limit mechanism, rotation amount detection unit, display, and control unit to compute and display accurate rotation angles, and a tilt limit mechanism, tilting amount detection unit, and control unit to compute and display accurate tilting angles, ensuring alignment with predetermined positions despite errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a digital display portion is provided to display angular rotation angle and tilting angle using detection units, then angle measurement capability is improved, but machining errors and assembly errors cause display inaccuracy
Solution Approach 1:
The system performs preliminary calibration by detecting when the turntable reaches predetermined rotation angles (0°, 45°, 90°, 135°) using the rotation limit mechanism, and stores correction values in the control unit's memory. This preliminary action compensates for manufacturing errors before actual measurement operations begin.
Solution Approach 2:
The control unit continuously compares the detected rotation angle from the optical sensor with the predetermined reference angles, applies correction values stored from calibration, and displays the corrected angle. This feedback loop ensures accurate angle display despite manufacturing variations in the mechanical components.
2Difficulty of detecting and measuring
If a rotation amount detection unit using optical sensors is used, then rotation angle detection capability is improved, but pulse counting errors occur due to machining and assembly variations
Solution Approach 1:
The system performs preliminary detection at predetermined rotation angles using the rotation limit mechanism to establish reference pulse counts. These reference values are stored in memory and used to correct subsequent measurements, compensating for manufacturing errors in the optical detection system.
Solution Approach 2:
The control unit uses feedback from the optical sensor to detect rotation angle, compares it with predetermined reference angles, applies correction values, and displays the corrected angle. This feedback mechanism eliminates pulse counting errors caused by manufacturing variations.
3Stability of the object's composition
If limiter arrangements are provided for fixing angular rotational positions, then rotation position stability is improved, but the system cannot compensate for manufacturing errors in achieving exact predetermined angles
Solution Approach 1:
The system performs preliminary detection at the predetermined angles established by the rotation limit mechanism and stores correction values. This preliminary action allows the system to account for manufacturing errors in the limiter positions while maintaining the stability benefit of fixed positions.
Solution Approach 2:
The control unit uses feedback to compare the position detected by the optical sensor with the predetermined angles, applies correction values from calibration, and displays the corrected angle. This maintains position stability while achieving angle precision.
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
The solution ensures accurate display of rotation and tilting angles, preventing user misconceptions about the tool's functionality and maintaining precision in angular adjustments.
Implementation Method 1
The optical sensor unit includes a light emitting element, a disc like element, and an optical sensor. The disc like detected element is rotatable in synchronism with the rotation of the turntable and is formed with a plurality of slits arrayed in a circumferential direction of the disc and spaced away from each other by a constant distance in the circumferential direction. The disc like element generates optical pulse each time the light passes through each slit and non-slit region shuts off the light. The optical pulse is detected by the optical sensor.
Data Source
AI summary
A miter saw including a base, a turntable, and a circular saw unit supported to the turntable. A turntable is rotatable about its axis, and a rotation limit mechanism is provided for limiting rotation of the turntable at a predetermined angle such as 45 degrees. A rotation amount detection unit is provided for detecting rotation amount of the turntable. A control unit is provided for displaying the rotation angle at a display. The control unit computes correction value that makes a rotation angle to be displayed at the display to be coincident with the predetermined rotation angle when the turntable is rotated to the predetermined rotation angle. The rotation angle is computed based on the correction value and on the rotation amount detected by the rotation amount detection unit.