Vibration Motor Controller Frequency Phase Switching
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Solution Overview
Problem
Existing speed control methods for vibration-type motors do not sufficiently utilize the original speed variable range, as they either rely solely on frequency control or phase difference control, leading to unstable speed and limited controllable ranges.
Innovation Solution
A vibration-type motor controller that alternately switches between frequency control and phase difference control, adjusting frequencies and phase differences to increase and decrease driving speed, thereby utilizing the full speed variable range of the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency control is used to change the frequency of frequency signals applied to the piezoelectric element, then the driving speed can be controlled, but the controllable speed range is limited and speed stability deteriorates when frequency is far from resonance frequency
Solution Approach 1:
The patent combines frequency control and phase difference control into a unified control system. The controller switches between frequency control (for wide speed range) and phase difference control (for speed stability near resonance frequency), thereby resolving the contradiction between speed range and speed stability that exists when using either control method alone.
2Speed
If phase difference control is used to change the phase difference of frequency signals, then the driving speed can be controlled, but the controllable speed range is limited and speed becomes unstable when phase difference is away from ±90 degrees
Solution Approach 1:
The patent merges phase difference control with frequency control, using phase difference control for precise speed adjustment near resonance frequency where it provides good stability, and switching to frequency control when wider speed range is needed, thus overcoming the limited adaptability of phase difference control alone.
3Device complexity
If only frequency control is used, then the control method is simple, but the speed control resolution is insufficient and the original speed variable range is not sufficiently utilized
Solution Approach 1:
The patent segments the speed control range into different zones: using frequency control for coarse speed adjustment and wide range control, and phase difference control for fine speed adjustment and high-resolution control near resonance frequency. This segmentation improves speed control resolution without significantly increasing overall system complexity.
4Speed
If the frequency is set far from resonance frequency to achieve lower speed, then the speed can be reduced, but the speed stability deteriorates and the motor stops at predetermined frequency
Solution Approach 1:
The patent introduces phase difference control as an intermediary mechanism when operating near resonance frequency. Instead of directly controlling speed through frequency alone (which causes instability), the system uses phase difference adjustment as a mediator to maintain speed stability while achieving the desired speed reduction, preventing premature motor stoppage.
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 approach allows for stable and efficient control of the vibration-type motor across a wider speed range, ensuring optimal performance and utilization of the motor's capabilities.
Implementation Method 1
an electromechanical energy conversion element (also referred to as a piezoelectric element or an electrostrictive element) is bonded
Implementation Method 2
the vibrating body and the contacting body are relatively moved to generate a driving force
Data Source
AI summary
A vibration-type motor controller controls a driving speed of a vibration-type motor relatively moving a vibrating body in which a vibration is excited by an electromechanical energy conversion element 20 to which a first frequency signal and a second frequency signal having a phase difference are applied, and a contacting body which contacts the vibrating body. The vibration-type motor controller includes a speed controller 1 configured to alternately switch a frequency control which changes frequencies of the first and second frequency signals while fixing the phase difference and a phase difference control which changes the phase difference while fixing the frequency so that at least one of a plurality of frequency controls or a plurality of phase difference controls are included to increase and decrease the driving speed of the vibration-type motor.