Rear Wheel Acceleration Estimation Using a Distance-Based Buffer
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Solution Overview
Problem
Existing electronically controlled suspension systems face challenges in accurately estimating rear wheel acceleration due to differences in suspension structure and vehicle specification between front and rear wheels, leading to deteriorated acceleration estimation performance, especially when vehicle velocity changes.
Innovation Solution
The system employs a distance-based buffer that stores vehicle velocity information alongside front wheel acceleration values, compensating rear wheel acceleration by reflecting the ratio of acceleration sizes between front and rear wheels, thereby enhancing estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a time-based buffer is used to estimate rear wheel acceleration by storing front wheel acceleration values, then the system structure remains simple, but the acceleration estimation performance deteriorates when vehicle velocity changes
Solution Approach 1:
The patent changes the buffer indexing parameter from time-based to distance-based. Instead of using a fixed time interval to access buffer values, the system calculates the distance corresponding to the wheelbase and uses this distance value to index into the buffer. This parameter change allows the system to accurately account for vehicle velocity variations, as distance = velocity × time, thereby resolving the contradiction between simple structure and accurate estimation under varying velocity conditions
Solution Approach 2:
The patent introduces distance as an intermediary parameter between time and acceleration values. By storing distance information alongside acceleration values in the buffer and using this distance information to select the appropriate buffer value, the system mediates the relationship between time-based sampling and distance-based wheelbase compensation. This intermediary approach enables accurate rear wheel acceleration estimation while maintaining the simplicity of the buffer structure
2Ease of operation
If acceleration values are allocated using a fixed time interval assuming constant vehicle velocity, then the processing method remains simple, but estimation accuracy deteriorates due to suspension structure differences and velocity changes
Solution Approach 1:
The patent changes the allocation method from fixed time interval to variable distance-based indexing. The system calculates the time required for the rear wheel to travel the wheelbase distance using the measured vehicle velocity, then uses this calculated time to index into the acceleration buffer. This parameter change transforms the allocation method from a simple but inaccurate fixed interval approach to a more complex but accurate velocity-compensated approach, resolving the contradiction between ease of operation and estimation accuracy
Solution Approach 2:
The patent makes the buffer access timing dynamic by using real-time vehicle velocity measurements. Instead of using a predetermined fixed time interval, the system continuously updates the buffer access time based on the current vehicle velocity and the known wheelbase distance. This dynamic adjustment allows the allocation method to adapt to changing velocity conditions, maintaining accuracy while preserving relative operational simplicity through automated calculation
3Device complexity
If the same acceleration value is used for both front and rear wheels without compensation, then the system remains simple, but accuracy deteriorates due to differences in suspension structure and vehicle specification
Solution Approach 1:
The patent segments the acceleration estimation process into distinct components: front wheel acceleration measurement, distance calculation based on wheelbase, velocity-based time calculation, and buffered value retrieval. By segmenting the system into acceleration sensors for front and rear wheels and implementing separate processing chains with distance-based buffering, the patent enables accurate compensation for suspension structure differences while maintaining system simplicity through modular design
Solution Approach 2:
The patent creates a virtual copy of the front wheel acceleration data at the appropriate time delay corresponding to the rear wheel position. By storing front wheel acceleration values in a distance-based buffer and retrieving the value that corresponds to the rear wheel's position in space and time, the system creates an accurate copy that accounts for the wheelbase distance and velocity variations. This copying approach enables accurate rear wheel acceleration estimation without requiring additional physical sensors at the rear wheel
Data Source
AI summary
Provided is an electronically controlled suspension system for estimating a rear wheel acceleration, which includes: a sensor unit measuring an acceleration value of a front wheel; a storage unit storing the acceleration value of the front wheel; and a control unit electrically connected to the sensor unit and the storage unit, and storing the acceleration value of the front wheel in the storage unit, and estimating the acceleration value of a rear wheel by using the acceleration value of the front wheel, wherein the storage unit has a front wheel acceleration buffer, the front wheel acceleration buffer is constituted by several cells, and the several cells are distinguished by a distance index, and the control unit stores the acceleration value of the front wheel corresponding to the distance index in each of the several cells, and the acceleration value of the rear wheel is estimated as the acceleration value of the front wheel, which is stored in a cell positioned behind a location of the front wheel by a wheelbase distance.