Batteryless Absolute Encoder Position Verification
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Solution Overview
Problem
Existing batteryless absolute encoders lack the ability to automatically detect abnormalities in absolute position detection and are prone to errors due to external forces or mechanical damage, leading to unexpected operations, and face challenges in reducing size and increasing precision while maintaining accuracy.
Innovation Solution
A batteryless absolute encoder with a gear mechanism coupled to rotary absolute position detectors, including an absolute position computing section, a non-volatile memory for storing positions, and a determining section that outputs an alarm signal for accuracy verification and detects movement beyond predetermined ranges, allowing for improved accuracy and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of teeth of gears is increased to increase the detectable range, then the detectable range is improved, but the allowable error of absolute position detectors must be reduced, increasing production cost
Solution Approach 1:
The patent divides the detection function into multiple independent resolvers (first resolver for revolution count, second resolver for position within revolution). This segmentation allows each resolver to operate with standard precision requirements while collectively achieving a large detectable range through the gear mechanism's tooth count multiplication.
2Shape
If gears are enclosed in a resolver with large diameter to achieve flat configuration, then the configuration is improved, but manufacturing becomes difficult when encoder size is small
Solution Approach 1:
The patent transitions from a planar arrangement where gears are enclosed in a large-diameter resolver to a three-dimensional stacked configuration. Multiple resolvers and gears are arranged vertically in layers, enabling compact encoder design while maintaining the gear mechanism's functionality and flat profile where needed.
3Device complexity
If one resolver is used to determine both which portion of revolution the spindle is at and the number of revolutions, then device complexity is reduced, but the resolver requires significant precision increasing production cost
Solution Approach 1:
The patent separates the detection functions into two independent resolvers: the first resolver specifically counts revolutions, while the second resolver determines the position within the current revolution. This functional segmentation allows each resolver to be designed with appropriate, less stringent precision requirements compared to a single multi-functional resolver.
4Use of energy by moving object
If non-volatile memory with fast writing speed is used to eliminate need for large capacity capacitor, then use of energy is improved, but device complexity increases
Solution Approach 1:
The patent replaces the traditional capacitor-based charge storage mechanism with a non-volatile memory device that inherently retains data without requiring continuous power or large capacity capacitors. This substitution eliminates the need for energy-intensive capacitor charging while providing reliable absolute position information retention during power-off states.
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 enables accurate detection of absolute position information, prevents unexpected operations by issuing alarms for inaccuracies, and allows for a smaller encoder design by using non-volatile memory and a counter section to track detection range exceedances.
Implementation Method 1
Writing into the non-volatile memory is performed using only an electric charge accumulated in a capacitor provided on a circuit substrate when electric power is turned off
Implementation Method 2
As the rotary absolute position detectors for use in the present invention, reluctance resolvers or optical absolute position detectors may be used
Data Source
AI summary
A batteryless absolute encoder determines the accuracy of absolute position information to be output when electric power is turned on and outputs an alarm signal in the case of abnormality. The batteryless absolute encoder includes an absolute position computing section, an absolute position storing section, and a determining section. The absolute position computing section computes the absolute position of a spindle to be detected, including the number of revolutions of the spindle, based upon detection signals output from four reluctance resolvers. The absolute position storing section stores the absolute position output from the absolute position computing section when electric power is turned off. The determining section compares an absolute position output from the absolute position computing section when electric power is turned on and the stored absolute position and outputs an alarm signal if a difference between the two absolute positions is larger than a predetermined value.