Vehicle State Estimation via Wheel Speed Phase Components
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Solution Overview
Problem
Existing vehicle state estimation systems face challenges in accurately estimating state quantities of a vehicle's sprung without relying on a vehicle model, particularly when actual vehicle characteristics change due to driving operations.
Innovation Solution
A vehicle state estimation device that calculates state quantities of a vehicle's sprung based on wheel speeds from four wheels, including in-phase and reverse phase components, to estimate pitch, yaw, vertical speed, and roll angular speeds without using a vehicle model or requiring information on suspension strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vehicle model is used to estimate speeds of unsprungs relative to a sprung, then the estimation can be performed, but accuracy lowers when actual vehicle characteristics shift from the model due to driving operation input
Solution Approach 1:
The invention extracts and eliminates the vehicle model from the estimation system. Instead of using a vehicle model that requires correction when characteristics change, the system directly calculates speeds of unsprungs relative to a sprung based on wheel speeds and driving operation input, removing the source of accuracy degradation.
Solution Approach 2:
The system uses readily available data (wheel speeds and driving operation input) to self-calculate the required estimation without external model assistance. This self-service approach allows the system to adapt automatically to changing driving conditions without requiring model corrections.
2Ease of operation
If a vehicle model is used for estimation, then theoretical framework is provided, but it is not easy to correct the model successively in accordance with actual vehicle characteristics
Solution Approach 1:
The invention removes the vehicle model from the estimation process entirely, eliminating the operational burden of model correction. The system directly computes estimates from measured data, making the system easy to operate while maintaining reliability.
3Reliability
If wheel speeds and driving operation input are used with a vehicle model, then speeds of unsprungs can be estimated, but the system becomes complex requiring model maintenance
Solution Approach 1:
The invention extracts and removes the complex vehicle model from the system, retaining only the essential calculation based on wheel speeds and driving operation input. This simplifies the system architecture while preserving the core estimation capability.
Solution Approach 2:
The system performs self-calibration by using actual measured data (wheel speeds and driving input) to directly compute estimates without requiring external model maintenance. This self-service mechanism reduces system complexity while maintaining reliability.
Data Source
AI summary
Provided is a vehicle state estimation device (10) having a calculation unit (28) that calculates state quantities of at least a sprung of a vehicle based on wheel speeds of front left and right wheels and rear left and right wheels detected by detection devices. The calculation unit (28) calculates in-phase and reverse phase components of wheel speeds of left and right wheels for the front and rear wheels and calculates a pitch angular speed and a yaw angular speed of the sprung based on the in-phase and reverse phase components of the wheel speeds, respectively. The calculation unit (28) calculates in-phase and reverse phase components of vertical strokes of left and right suspensions for the front and rear wheels and calculates a vertical speed and a roll angular speed of the sprung based on the in-phase and reverse phase components of vertical strokes of the suspensions, respectively.