Adaptive Noise Control Using Variable Actuator Participation
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Solution Overview
Problem
Active noise control systems face challenges in optimizing their configuration to effectively reduce noise across various operating conditions, such as different motor speeds or engine thrusts, leading to suboptimal performance in vehicle compartments.
Innovation Solution
The method involves arranging actuators and error sensors in the vehicle compartment to actively control noise power at multiple control positions, using adaptive filters and algorithms to adjust filter coefficients based on noise source operating conditions, with an actuator and error sensor weighting device determining weighting factors to optimize noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed ANC system configuration is used, then the system structure is simple, but the noise reduction performance is suboptimal across different operating conditions
Solution Approach 1:
The patent implements dynamic adaptation by allowing the ANC system to automatically adjust actuator and error sensor weighting factors based on real-time operating conditions. The system transitions from a fixed configuration to a dynamic one where participation factors are continuously optimized according to the current noise environment and operational state, resolving the contradiction between simplicity and adaptability.
Solution Approach 2:
The system changes key parameters (weighting factors and participation factors) of the ANC configuration based on operating conditions. By modifying these parameters dynamically rather than changing the physical structure, the system achieves adaptability while maintaining relative structural simplicity, thus resolving the technical contradiction.
2Reliability
If multiple actuators and sensors are used to optimize noise control, then the noise reduction effectiveness improves, but the system complexity and computational load increase
Solution Approach 1:
The patent applies partial action by using weighting factors to selectively emphasize certain actuators and error sensors based on current operating conditions. Rather than requiring all components to be equally effective at all times, the system achieves reliable noise control by activating or emphasizing only the necessary subset of components for each specific condition, thus improving effectiveness without proportionally increasing complexity.
Solution Approach 2:
The dynamic adjustment of participation factors allows the system to optimize the contribution of each actuator and sensor based on real-time needs. This dynamic allocation ensures that the system maintains high noise control effectiveness while avoiding the permanent complexity of having all components actively engaged in all operating scenarios.
3Productivity
If the ANC system is adapted to different operating conditions, then the noise control performance improves, but the computational complexity and processing requirements increase
Solution Approach 1:
The system achieves improved noise control performance by dynamically changing parameter sets (weighting factors) rather than reconfiguring the entire system architecture. This parameter-based adaptation approach allows the system to respond to different operating conditions with improved performance while keeping computational complexity manageable through focused parameter optimization rather than full system reconfiguration.
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 adaptive noise control that optimizes the placement and contribution of actuators and sensors across different operating conditions, significantly reducing residual noise in both control and monitor positions within the vehicle compartment.
Implementation Method 1
The actuators generate secondary sound waves, aiming at having amplitude and phase opposite to that of the primary sound waves in the compartment. The secondary sound waves interact with the primary sound waves, thereby eliminating or at least reducing the disturbing noise within the compartment.
Implementation Method 2
Residual noise in the compartment is sensed using error sensors. The resulting error sensor output signals are used as 'error signals' and are provided to an adaptive algorithm, wherein the filter coefficients of the adaptive filters are modified such that a cost function (e.g., norm or the power of the error signal) and, thereby, the residual noise in the compartment is minimized.
Data Source
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AI summary
A method for reducing noise in at least one monitor position in a vehicle compartment by actively controlling the power of a primary noise (dm(t)) as sensed at two or more control positions in the vehicle compartment, the method comprising the updating of filter coefficient(s) of (an) adaptive filter(s) (w(n)) based on variable contribution of error sensors and actuator(s) for different noise source operating conditions.