Stepping Motor Advance Angle Control via Phase Feedback
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Solution Overview
Problem
Existing stepping motor control methods face challenges in maintaining optimal advance angle control due to individual motor and load differences, temperature changes, posture variations, and counter electromotive force, leading to inefficiencies and noise generation, especially at low rotation speeds.
Innovation Solution
A motor control device that detects the rotational phase of a stepping motor, generates a driving waveform, and controls its phase difference by adjusting the amplitude or period, using a processor to determine a target phase difference and optimize the waveform for efficient torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the period of driving waveform is changed to match advance angle value in microstep drive, then high speed rotation efficiency is improved, but detection period of position sensor increases and noise is generated in low speed region
Solution Approach 1:
The patent dynamically adjusts the advance angle based on the actual phase difference detected between the driving waveform and rotor position, rather than using a fixed advance angle value. The control unit continuously monitors the phase difference and modifies the driving waveform period accordingly, enabling the system to adapt to varying speed conditions and avoid noise generation in low speed regions while maintaining efficiency in high speed regions.
Solution Approach 2:
The patent implements a feedback mechanism where the actual phase difference between the driving waveform and rotor position is detected and used to adjust the advance angle. The control unit receives position sensor signals, calculates the actual phase difference, and modifies the driving waveform period to minimize this difference, thereby eliminating noise without sacrificing speed performance.
2Productivity
If experimental data of relationship between advance angle and rotation speed is stored in memory, then target advance angle can be set, but individual difference between motor and moving member and load changes cause suboptimal control state
Solution Approach 1:
The patent replaces static experimental data with a dynamic feedback system that continuously measures the actual phase difference between the driving waveform and rotor position. This real-time feedback enables the control unit to adapt to individual motor characteristics, load changes, temperature variations, and posture differences, maintaining optimal control efficiency under all operating conditions.
Solution Approach 2:
The patent changes the control parameter from a fixed advance angle value based on experimental data to a dynamically adjusted advance angle determined by actual phase difference measurement. This parameter change allows the system to adapt to individual differences between motors and moving members, as well as to load changes, temperature variations, and posture differences.
3Loss of energy
If advance angle is controlled to maximize rotation efficiency, then power saving is achieved, but counter electromotive force causes phase deviation and reduces control accuracy
Solution Approach 1:
The patent uses feedback to continuously detect the actual phase difference between the driving waveform and rotor position, compensating for phase deviations caused by counter electromotive force. By measuring the true phase relationship in real-time, the system maintains accurate advance angle control despite the effects of counter electromotive force, preserving both energy efficiency and control precision.
Data Source
AI summary
In a motor control device, a rotational phase detection unit detects a rotational phase of a rotor of a stepping motor, and a driving waveform generation unit generates a driving waveform for driving the stepping motor. An advance angle control unit detects a phase difference (advance angle) between a rotational phase of the rotor and a phase of the driving waveform and controls an amplitude or a period of the driving waveform generated by the driving waveform generation unit to perform advance angle control. The advance angle control unit controls an amplitude of the driving waveform by determining a target advance angle based on a variation (advance angle change rate) of an advance angle with respect to a variation of an amplitude in accordance with a change in the advance angle when the amplitude of the driving waveform is changed.