Stepping Motor Load Detection Using Swinging Pulses
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Solution Overview
Problem
Existing stepping motor control systems face challenges in detecting the rotation state of the rotor due to low induced voltage generation, making it difficult to determine the mechanical load and control the energy efficiently for accurate hand position detection in timepieces.
Innovation Solution
A stepping motor control device that includes a driving unit, a control unit, a voltage detecting unit, and a determining unit, which outputs driving and swinging pulses to rotate and vibrate the rotor, detects induced voltage, and determines mechanical load by controlling energy based on the detected voltage and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a normal driving pulse is applied to the stepping motor, then the rotor rotates and generates an induced voltage, but the induced voltage may be too low to reliably detect the rotation state
Solution Approach 1:
The patent applies a swinging pulse to vibrate the rotor before applying the driving pulse. This vibration increases the rotor's speed and kinetic energy, enabling it to generate a sufficiently large induced voltage when it rotates under the driving pulse, thereby solving the problem of low induced voltage generation and unreliable rotation state detection
Solution Approach 2:
The patent applies the swinging pulse before the driving pulse to preliminarily accelerate and vibrate the rotor. This preliminary action ensures that when the driving pulse is applied, the rotor is already in a state capable of generating detectable induced voltage, thus improving measurement precision and reliability
2Measurement precision
If the rotor vibrates at constant or higher speed to generate sufficient induced voltage, then detection becomes possible, but energy consumption increases
Solution Approach 1:
The patent applies the swinging pulse periodically at predetermined intervals before driving pulses. This periodic vibration approach allows the rotor to maintain sufficient speed for reliable induced voltage detection only when necessary, rather than continuous vibration, thereby reducing overall energy consumption while maintaining measurement precision
Solution Approach 2:
The patent applies a swinging pulse that provides just enough energy to vibrate the rotor to the required speed for detection, avoiding excessive energy input. This partial action approach ensures sufficient induced voltage generation without unnecessary energy waste
3Measurement precision
If the rotor is swung before driving to improve detection, then rotation state can be reliably detected, but the control system complexity increases
Solution Approach 1:
The control unit performs multiple functions: it generates both swinging pulses for vibration and driving pulses for rotation, and it determines mechanical load based on induced voltage detection. This multi-functionality integrates the vibration and detection processes into a single control unit, avoiding the need for separate complex subsystems
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 solution enables reliable detection of the rotor's rotation state and mechanical load, preventing stepping motor misalignment and ensuring accurate hand position detection by adjusting energy output according to load conditions, even in cases where induced voltage is low.
Implementation Method 1
a coil that generates a magnetic flux for rotating the rotor
Implementation Method 2
an induced voltage generated in the coil when the rotor vibrates
Data Source
AI summary
A stepping motor control device includes a driving unit that drives a stepping motor including a rotor that rotates a hand and a coil that generates a magnetic flux for rotating the rotor, a control unit that outputs, to the driving unit, a driving pulse for rotating the rotor and a swinging pulse for swinging the rotor, a voltage detecting unit that detects an induced voltage generated in the coil when the rotor vibrates, and a determining unit that determines, based on a result of the detection of the voltage detecting unit, a mechanical load received by the rotor.