Deceleration Factor Estimation via Road Load Filtering
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Solution Overview
Problem
Existing drive assisting devices face accuracy issues in estimating deceleration factors, which are crucial for vehicle control, due to variations in air resistance and vehicle weight, leading to inaccuracies in calculating road load components.
Innovation Solution
A deceleration factor estimating device that includes a road load calculating unit and a filtering calculating unit to extract specific frequency components of road load, allowing for accurate estimation of deceleration factors by distinguishing between vehicle-originated and environment-originated road load components, and using these to adjust control units for drive assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If deceleration factors are estimated by calculating various conditions (air resistance, rolling resistance, vehicle weight), then the vehicle control can be performed based on estimated values, but the accuracy of estimation is lowered when estimated values deviate from actual values
Solution Approach 1:
The road load estimated value is segmented into multiple frequency components through filtering processing. The total road load component is extracted using a first time constant filter, while the vehicle-originated road load component is extracted using a second time constant filter with a longer period. This segmentation allows separate analysis and compensation of different road load sources, improving estimation accuracy while maintaining control capability.
Solution Approach 2:
The system uses filtering processing to continuously process the road load estimated value and extract meaningful components. By comparing the total road load component with the vehicle-originated road load component, the system generates feedback information about environment-originated road load, which is then used to improve the accuracy of deceleration factor estimation for subsequent control operations.
2Measurement precision
If filtering processing is applied to extract frequency components of road load, then the accuracy of deceleration factor estimation is improved, but the device complexity increases
Solution Approach 1:
The filtering calculating unit acts as an intermediary between the road load calculating unit and the deceleration factor estimating unit. It processes the road load estimated value through filtering operations with different time constants, extracting total road load component and vehicle-originated road load component. This intermediary processing improves accuracy without requiring fundamental changes to the overall system architecture.
Data Source
AI summary
A deceleration factor estimating device that estimates a deceleration factor of a vehicle includes a road load calculating unit configured to calculate a road load estimated value, and a filtering calculating unit configured to perform filtering processing of extracting a predetermined frequency component of the road load estimated value calculated by the road load calculating unit. The filtering calculating unit extracts a vehicle-originated road load component, an environment-originated road load component, and the like by filtering the road load estimated value to extract a certain predetermined frequency component.