Active Suspension Spring Constant Estimation in Stopped Vehicles
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Solution Overview
Problem
Existing vehicular state estimation systems face challenges in accurately calculating spring constants due to wear, deterioration, and variations in vehicle components, which affects the accuracy of vehicle behavior estimation.
Innovation Solution
A vehicular state estimation apparatus that includes a physical quantity detector, a vehicle behavior estimator, a distance sensor, a distance calculator, a spring constant calculator, and a suspension controller. This apparatus detects vehicle behavior, estimates current vehicle behavior, calculates road surface distance, and calculates spring constants of the active suspension apparatus in a stopped state to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spring constants are calculated based on design-based theoretical values, then the calculation process is simple, but the accuracy deteriorates due to wear, deterioration, error or variation in components
Solution Approach 1:
The system performs preliminary action by detecting physical quantities and estimating vehicle behavior before final spring constant calculation. The vehicle behavior estimator uses detected physical quantities to predict vehicle behavior, which then informs the spring constant calculator to determine accurate spring constants that account for component wear and deterioration, rather than relying solely on design theoretical values.
Solution Approach 2:
The system implements feedback by using detected physical quantities and estimated vehicle behavior to continuously update and refine spring constant calculations. The suspension controller receives feedback from the vehicle behavior estimator and adjusts spring constant values based on actual vehicle performance data, creating a closed-loop system that improves accuracy over time while adapting to component variations and wear.
2Measurement precision
If spring constants are calculated when the vehicle is traveling, then real-time data is available, but accuracy deteriorates compared to stopped state measurements
Solution Approach 1:
The system applies dynamics by enabling the spring constant calculation to adapt between different vehicle states. The suspension controller determines whether to calculate spring constants using stopped state data (higher accuracy) or traveling state data (faster response), dynamically switching between calculation modes based on vehicle operating conditions to optimize both accuracy and timeliness.
Solution Approach 2:
The system performs preliminary action by calculating spring constants during stopped states when high accuracy is achievable, then storing these values for use during traveling states. This preliminary calculation during stationary periods prepares accurate spring constant values that can be quickly applied when the vehicle begins moving, reducing the need for complex real-time calculations during travel.
3Reliability
If design-based theoretical values are used for spring constants, then component variations are ignored, but accuracy deteriorates due to wear and deterioration
Solution Approach 1:
The system implements feedback by continuously monitoring physical quantities and vehicle behavior to detect deviations from design-based theoretical values. The spring constant calculator uses this feedback to adjust spring constant values, automatically compensating for component wear, deterioration, and manufacturing variations. This creates a self-correcting system that maintains reliability despite component aging and variations.
Solution Approach 2:
The system applies parameter changes by dynamically modifying spring constant values based on detected vehicle behavior and physical quantities. Rather than using fixed design-based theoretical values, the system adjusts spring constant parameters to reflect actual component conditions, including wear and deterioration, thereby improving reliability and accounting for component variations throughout the vehicle's operational life.
Data Source
AI summary
The vehicular state estimation apparatus includes: a physical quantity detector configured to detect a physical quantity indicating behavior by the vehicle; a vehicle behavior estimator configured to estimate current behavior by the vehicle; a distance sensor that is configured to detect a value pertaining to a distance between the vehicle body member and a measurement point on a road surface in front of the vehicle and corresponding to at least a central section of a road surface contact section on a wheel; a distance calculator configured to calculate a road surface distance; a spring constant calculator configured to calculate at least one of spring constants, in a vehicle stopped state; and a suspension controller configured to control operation of the active suspension apparatus based on the spring constants, the road surface distance, and vehicle behavior information.