Vehicle Control Device Pitch Motion Estimation Accuracy
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Solution Overview
Problem
Existing vehicle control systems face accuracy issues in estimating stroke speed during disturbances in wheel speed, leading to deteriorated control of vehicle body orientation, particularly when estimation accuracy of the sprung mass state declines.
Innovation Solution
A vehicle control device that estimates pitch motion based on wheel speed information and controls friction brakes to achieve a target pitch motion, gradually reducing brake control as estimation accuracy deteriorates, utilizing sensors to monitor wheel speed and adjust braking torque accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stroke speed is estimated from wheel speed fluctuations in a predetermined frequency region, then control of vehicle body orientation can be achieved, but estimation accuracy deteriorates when wheel speed disturbance occurs in that frequency region
Solution Approach 1:
The patent introduces an estimation accuracy detection unit as an intermediary that monitors the reliability of stroke speed estimation. When wheel speed disturbance occurs in the predetermined frequency region, this unit detects the deterioration and triggers a switch to alternative control strategies, preventing erroneous control actions while maintaining system reliability
Solution Approach 2:
The control system dynamically adjusts its operation mode based on estimation accuracy. When estimation accuracy is high, the system uses normal stroke speed-based control. When accuracy deteriorates due to wheel speed disturbance, the system switches to alternative control modes, creating a dynamic adaptation mechanism that maintains reliability under varying conditions
2Stability of the object's composition
If friction brakes are controlled to achieve target pitch motion, then vehicle body orientation is stabilized, but driver discomfort increases when estimation accuracy deteriorates
Solution Approach 1:
The system incorporates feedback from the estimation accuracy detection unit to modulate brake control actions. When estimation accuracy deteriorates, the feedback mechanism reduces or suspends brake control, preventing erroneous corrections that would cause driver discomfort while maintaining vehicle stability through alternative means
Data Source
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AI summary
This device has a sensor for detecting wheel speed. A control device estimates a sprung mass state based on information in a prescribed frequency range of wheel speed detected by the sensor, controls a friction brake so as to bring the sprung mass state to a target sprung mass state, and, in instances where the estimated accuracy at which the pitch motion amount deteriorates, gradually lowers the amount by which the friction brakes are controlled.