Active Noise Control Device Peak Frequency Impedance Adaptation
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Solution Overview
Problem
Existing active noise control devices, such as those described in JP H06-059688 A, fail to effectively reduce noise when changes occur in the characteristics of the sound generating device, leading to inadequate noise cancellation in vehicle compartments.
Innovation Solution
An active noise control device that includes a control signal generating unit with an adaptive filter, an identifying unit to detect peak frequencies in the actuator's impedance frequency characteristic, and a control unit that adjusts the control signal characteristics when significant changes are detected, ensuring effective noise cancellation despite changes in the actuator's characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional active noise control device is used, then noise cancellation is achieved under initial conditions, but noise reduction effectiveness deteriorates when actuator characteristics change over time
Solution Approach 1:
The patent implements feedback by continuously monitoring the actuator's impedance frequency characteristics and using this information to adjust the control signal. The identifying unit detects peak frequencies in real-time, and this feedback loop ensures the control signal adapts to characteristic changes, maintaining noise cancellation effectiveness throughout the actuator's operational life.
Solution Approach 2:
The patent applies dynamics by making the control signal characteristics variable rather than fixed. The control signal generating unit dynamically adjusts the control signal based on detected peak frequency changes, allowing the system to adapt to actuator characteristic variations over time and maintain optimal noise cancellation performance.
2Reliability
If the control signal characteristics are dynamically adjusted, then noise cancellation effectiveness is maintained, but device complexity increases
Solution Approach 1:
The patent segments the control system into distinct functional units: an identifying unit for detecting peak frequencies, a determination unit for comparing frequency changes, and a control signal generating unit for adjusting control signals. This segmentation allows each unit to perform its specific function efficiently, managing overall system complexity through modular design.
Solution Approach 2:
The patent changes parameters (specifically control signal characteristics) based on detected peak frequency shifts rather than redesigning the entire control system. By adjusting existing parameters dynamically, the system maintains effectiveness without requiring fundamentally more complex architecture.
Data Source
AI summary
An active noise control device includes a control signal generating unit including a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, an identifying unit configured to identify a peak frequency in an impedance frequency characteristic of an actuator, a peak frequency storage unit configured to store an initial peak frequency of the actuator, a first determination unit configured to determine whether or not a difference between the peak frequency currently identified and the initial peak frequency is greater than or equal to a threshold value, and a control unit configured to change a characteristic of the control signal generated by the control signal generating unit when the first determination unit determines that the difference is greater than or equal to the threshold value.