Active Suspension Road Height Correction for Ride Comfort
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Solution Overview
Problem
Existing active suspension control devices risk deteriorating ride comfort when road surface detection is abnormal, leading to inadequate control of rear wheel actuators based on estimated vertical acceleration.
Innovation Solution
An active suspension device with a road surface height measurer, position detector, and corrector that measures road surface heights at multiple points, detects significant differences, and corrects road surface heights exceeding a threshold to predetermined deformation limits, preventing abnormal ride conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator of the rear wheels is controlled depending on the vertical acceleration estimated from the vertical acceleration stored in the storage when the detection of the displacement is abnormal, then the control device can still operate without a road surface detector, but the ride comfort of the occupant deteriorates
Solution Approach 1:
The patent introduces an intermediary estimation mechanism that uses vertical acceleration data and vehicle dynamics parameters (wheel base, vehicle speed) to calculate predicted road surface displacement. This intermediary calculation serves as a bridge when direct road surface detection is unavailable, allowing the system to maintain operational reliability while improving the accuracy of suspension control compared to using only stored vertical acceleration data.
2Reliability
If the controller estimates the displacement of the road surface from the displacement stored in the storage when the vehicle travels for a predicted distance, then the suspension control can be maintained, but measurement errors from abnormal road surface detection (stones, woven wires) cause ride comfort deterioration
Solution Approach 1:
The patent applies preliminary action by detecting road surface heights at multiple points ahead of the wheel and identifying positions with abnormal height differences before the wheel reaches them. By detecting and flagging these abnormal positions in advance, the system can exclude contaminated measurement data from the displacement estimation calculation, thereby maintaining measurement precision while preserving suspension control continuity.
Solution Approach 2:
The patent segments the road surface measurement into multiple discrete measurement points along the vehicle-width direction. By dividing the continuous road surface into discrete segments and evaluating each segment's height difference independently, the system can identify and exclude only the abnormal segments (those with stones or woven wires) while still utilizing data from normal segments, thus maintaining overall measurement precision.
3Measurement precision
If the road surface height is measured at multiple points along the vehicle-width direction, then the position of road surface irregularities can be detected, but the device complexity increases
Solution Approach 1:
The patent makes the road surface detector multi-functional by enabling it to perform both continuous road surface height measurement and abnormal position detection using the same hardware components. The detector measures heights at multiple points and simultaneously calculates height differences to identify abnormal positions, eliminating the need for separate detection systems and thereby reducing overall device complexity while maintaining high measurement precision.
Data Source
AI summary
An ECU includes: a road surface height measurer which measures road surface heights at three or more points along a vehicle-width direction in front of a tire mounted on a wheel; a position detector which detects a position at which a difference of the road surface height from an adjacent road surface height is equal to or larger than a predetermined threshold among the road surface heights at three or more points measured by the road surface height measurer; and a corrector which corrects the road surface height at a position at which the difference detected by the position detector is equal to or larger than the predetermined threshold to a predetermined height.