Vehicle Actuator Noise Control Using Road Noise Estimation State
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Solution Overview
Problem
Existing methods for estimating road surface conditions from tire vibration waveforms are hindered by micro-vibrations caused by disturbances like mechanical brake operations or wheel slip, leading to reduced estimation accuracy and potential discomfort for vehicle occupants due to incorrect actuator output adjustments.
Innovation Solution
A control method that estimates road noise magnitude and adjusts in-vehicle actuator output based on road surface conditions, using a series hybrid vehicle configuration with a controller that processes various sensor inputs to differentiate between proper and improper estimation states, thereby minimizing noise-induced discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing method estimates road surface condition from tire vibration waveform, then the road surface condition can be estimated, but the estimation accuracy is lowered due to micro-vibrations from disturbance elements
Solution Approach 1:
The patent extracts and removes the harmful micro-vibrations caused by disturbance elements (brake operations, wheel slip) from the tire vibration waveform. By identifying and eliminating these specific disturbance components, the system isolates the true road surface condition signal, thereby improving estimation accuracy without being affected by the harmful vibrations.
Solution Approach 2:
The patent introduces an intermediary processing step that analyzes the tire vibration waveform to distinguish between road surface condition signals and disturbance element signals. This intermediary analysis mechanism acts as a filter or mediator that separates the useful information from the harmful vibrations before final estimation.
2Object-affected harmful factors
If the actuator output is increased to compensate for road noise, then the noise discomfort to occupant is reduced, but the actuator output may be incorrectly increased when estimation has error, causing unnecessary noise
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors the estimated road surface condition and adjusts the actuator output accordingly. By using the estimated road noise level as feedback, the system dynamically compensates for actual road noise conditions, reducing occupant discomfort while avoiding unnecessary actuator activation when estimation is accurate.
Solution Approach 2:
The patent performs preliminary estimation and validation of road surface conditions before adjusting actuator output. By pre-assessing the reliability of the estimation and the actual road noise level, the system prepares appropriate control actions only when necessary, preventing incorrect actuator activation while ensuring timely compensation when truly needed.
Data Source
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AI summary
When it is determined that an estimation state of a road noise value based on an angular acceleration of a wheel of a vehicle or a parameter related thereto is a proper estimation state, it is determined whether a background noise of the vehicle is in the high background noise state or the low background noise state according to magnitudes of the road noise value and a predetermined threshold value; when it is determined that the estimation state is not the proper estimation state, it is determined that the background noise of the vehicle is in the low background noise state regardless of the road noise value; when it is determined that the background noise of the vehicle is in the high background noise state, an output of the in-vehicle actuator is set so that a noise accompanying an operation of the in-vehicle actuator becomes relatively large; and when it is determined that the background noise of the vehicle is in the low background noise state, an output of the in-vehicle actuator is set so that a noise accompanying an operation of the in-vehicle actuator becomes relatively small.