Input Shaping Control for Voice Coil Actuator Vibration
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Solution Overview
Problem
Existing voice coil actuators in camera modules suffer from residual vibration due to high resonance response characteristics, which affects the auto-focus function and can cause malfunctions, and previous input shaping control methods do not adequately consider damping, limiting the effectiveness of vibration reduction.
Innovation Solution
An apparatus and method that utilize input shaping based on the resonance frequency and damping of the voice coil actuator to generate a control signal, using shaping signals such as multi-step or toggle signals with gradually decreasing fluctuations, to effectively reduce residual vibration by convoluting impulse sequences with reference signals and applying damping values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If input shaping control is applied to reduce residual vibration in voice coil actuator, then auto-focus function is improved, but the control method does not adequately consider damping which limits the effectiveness of vibration reduction
Solution Approach 1:
The patent applies parameter changes by incorporating damping ratio as an additional parameter in the input shaping control method. The shaping signal is designed based on both resonance frequency and damping ratio, transforming the control approach from considering only resonance frequency to considering both parameters simultaneously, thereby improving vibration reduction effectiveness
Solution Approach 2:
The patent uses feedback by measuring the actual vibration response of the voice coil actuator and adjusting the shaping signal parameters accordingly. The damping ratio is determined through feedback from the actuator's response, and this information is used to optimize the input shaping control for maximum vibration reduction
2Ease of manufacture
If conventional input shaping control is used without considering damping, then the control implementation is simple, but the residual vibration reduction effect is limited
Solution Approach 1:
The patent extends the conventional input shaping control by adding damping ratio as a parameter. The shaping signal is designed using both resonance frequency and damping ratio parameters, which maintains the simplicity of the input shaping approach while significantly improving the vibration reduction effectiveness through the additional parameter consideration
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 approach significantly enhances the auto-focus function of camera modules by effectively reducing residual vibration, leading to stable operation and accurate focusing without malfunctions, as demonstrated by simulation results showing reduced settling times and improved vibration reduction compared to methods that do not consider damping.
Implementation Method 1
a vibration plate of a speaker moves back and forth when a force caused by the Fleming's left hand rule between a voice current flowing through a voice coil of the speaker and a magnetic force produced by a permanent magnet
Implementation Method 2
the inductor (L) component of the voice coil actuator exhibits high resonance response characteristics due to its own resonance frequency and causes residual vibration during operation
Implementation Method 3
an input shaping unit which performs input shaping based on a resonance frequency of a voice coil actuator and damping of vibration in the voice coil actuator to generate a control signal
Data Source
AI summary
An apparatus for driving a voice coil actuator of a camera and a method thereof are provided. The driving apparatus performs input shaping based on a resonance frequency of a voice coil actuator and damping of vibration in the voice coil actuator to generate a control signal using a shaping signal as an initial input from an unshaped control signal, and thereby drives the voice coil actuator using the control signal subjected to input shaping. The shaping signal is provided to remove the resonance of the voice coil actuator, and may be a pure shaping signal, such as a multi-step shaping signal or a toggle shaping signal, or a convoluted shaping signal obtained by convoluting such pure shaping signals. The driving apparatus may significantly reduce residual vibration and may enhance an auto-focus function of the voice actuator using input shaping control based on damping.