Electronic Watch Motor Controller Frequency Ratio
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Solution Overview
Problem
Analog electronic watches with independent motors for hour and minute hands often cause discomfort due to the deceleration of the hour hand leading to a shift in the relative positional relationship between the hour and minute hands during fast-forward operations, disrupting the natural hand movement and user experience.
Innovation Solution
The electronic watch employs a motor controller that adjusts the drive frequencies of the motors for the hour and minute hands to maintain a predetermined angular velocity ratio, ensuring simultaneous and continuous hand movement during time correction and numerical value indication, mimicking the mechanical interlocking of traditional watch hands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If independent motors drive each hand separately during fast-forward operation, then each hand can be controlled independently, but the relative positional relationship between hands shifts causing user discomfort
Solution Approach 1:
The system dynamically adjusts the drive frequencies of independent motors based on the operational mode. During time correction mode, the controller sets specific frequency ratios between hour hand motor and minute hand motor to maintain proper angular velocity relationships, while in time display mode it uses different frequency settings. This dynamic frequency adjustment allows independent motor control while preserving the natural relative positioning of hands.
Solution Approach 2:
The controller changes the drive parameters (frequency and angular velocity) of the motors depending on the operation mode. By switching between time display mode parameters and time correction mode parameters, the system maintains appropriate hand movement relationships during fast-forward operations while preserving independent motor control capability.
2Stability of the object's composition
If the hour hand decelerates during fast-forward, then the minute hand can catch up to maintain position, but this creates an unnatural hand movement sequence
Solution Approach 1:
The system uses dynamic frequency adjustment where both motors run simultaneously at predetermined frequency ratios during time correction mode. This eliminates the sequential start-stop pattern and creates smooth, natural simultaneous movement of both hands while maintaining their proper relative positioning throughout the fast-forward operation.
3Stability of the object's composition
If simultaneous hand movement is implemented during time correction, then the positional relationship is maintained, but the control complexity increases
Solution Approach 1:
The system replaces complex mechanical interlocking mechanisms with an electronic control system that uses frequency ratio settings. The controller stores predetermined frequency ratios for different modes and automatically applies them, achieving simultaneous coordinated control of multiple motors through software rather than mechanical linkages, thereby reducing mechanical complexity while maintaining control precision.
Data Source
AI summary
An electronic watch includes a first hand that is rotated by a first motor, and indicates a higher digit of numerical information or time information, a second hand that is rotated by a second motor, and indicates a lower digit of the numerical information or the time information, and a motor controller. The motor controller performs a numerical value indication mode for driving the first motor and the second motor simultaneously to indicate an increase or decrease in the numerical information, or time correction mode for driving the first motor and the second motor simultaneously to correct the time information, and in the numerical value indication mode or the time correction mode, controls a drive frequency of the first motor and a drive frequency of the second motor such that angular velocity of hand movement of the first hand is less than angular velocity of hand movement of the second hand.