Stepping Motor Meter Needle Positioning via Pre-Offset
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Solution Overview
Problem
Existing indicating-needle type meter devices face challenges in accurately positioning the indicating-needle due to backlash in the gear mechanism and limited correction options for placing errors, leading to unnatural movements and potential jumping during excitation.
Innovation Solution
The device incorporates a controller that performs origin return processing by setting the excitation signal phase to a predetermined start position, reversing it to align the indicating-needle with a stopper, and then advancing it to an origin position, allowing for correction of placing errors in both forward and backward directions by adding a pre-offset angle, thereby increasing the degree of freedom in error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If origin return processing is performed by returning the excitation signal phase to align the indicating-needle with the stopper, then the indicating-needle positioning accuracy is improved, but the indicating-needle moves drastically which appears unnatural
Solution Approach 1:
The patent applies preliminary action by performing origin return processing at the start of excitation to pre-position the indicating-needle at the correct origin point. This ensures that subsequent measurements and movements start from an accurate reference position, improving positioning accuracy while the needle remains stationary during normal operation.
Solution Approach 2:
The patent implements preliminary anti-action by adding a pre-offset angle to the origin return angle. This pre-offset compensates for the backlash in the gear mechanism before the indicating-needle movement begins, preventing the unnatural drastic movement that would otherwise occur when the needle first engages with the gear teeth.
2Measurement precision
If the indicating-needle is positioned at the stopper position during origin return, then positioning reference is established, but placing errors cannot be corrected in both forward and backward directions
Solution Approach 1:
The patent applies parameter changes by introducing a pre-offset angle parameter that modifies the origin return angle. This allows the system to compensate for placing errors in both forward and backward directions by adjusting the angular parameter, thereby increasing error correction flexibility while maintaining the stopper position as the reference point.
3Measurement precision
If the excitation signal phase is advanced by the origin return angle, then the indicating-needle is positioned at the origin position, but backlash causes hysteresis and positional deviation
Solution Approach 1:
The patent implements preliminary anti-action by adding a pre-offset angle to the origin return angle. This pre-offset compensates for the backlash in the gear mechanism before the indicating-needle movement begins, ensuring that the driving force is transmitted reliably without hysteresis or positional deviation when the needle is positioned at the origin.
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 configuration ensures smooth and natural movement of the indicating-needle during excitation, prevents jumping, and allows for precise positioning, enhancing the accuracy and reliability of the meter device.
Implementation Method 1
By controlling an excitation signal to grasp the stepping number in the driving, it is possible to manage the rotational position of the indicating-needle
Data Source
AI summary
In an indicating-needle type meter device, when starting excitation of a stepping motor, a controller sets the phase of an excitation signal to a predetermined excitation start position and returns the phase of the excitation signal by a predetermined reversal angle such that an indicating-needle rotates in the backward direction, thereby positioning the indicating-needle at a stopper position. Subsequently, the controller advances the phase of the excitation signal by an origin return angle to rotate the indicating-needle in the forward direction to an origin position apart from the stopper position by a predetermined angle, thereby positioning the indicating-needle at the origin position. Here, the origin return angle is an angle obtained by adding a backlash angle, a predetermined positive pre-offset angle, and a positive placing error correction angle set based on a placing error of the indicating-needle with respect to the stopper.