Vehicle Control Device for Stable Sprung Mass Estimation
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining accurate estimation of the sprung mass state, particularly when wheel speed disturbances occur, leading to reduced accuracy and potentially unstable vehicle body orientation.
Innovation Solution
A control device and method that estimates the sprung mass state based on wheel speed information and adjusts the damping force of a variable damping force shock absorber to maintain a target state, transitioning to a fixed damping force when low accuracy is detected to prevent control errors and ensure stable vehicle orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If variable damping force shock absorber control is performed based on estimated sprung mass state, then vehicle body orientation control is improved, but control accuracy deteriorates when wheel speed disturbances occur
Solution Approach 1:
The system continuously monitors wheel speed information to detect disturbances and adjusts the control strategy based on the detected conditions. When wheel speed disturbances are detected, the system switches from variable damping force control to fixed damping force control, ensuring stable vehicle body orientation even when estimation accuracy deteriorates
Solution Approach 2:
The damping force control system dynamically switches between two operating modes: variable damping force control (when estimation accuracy is high) and fixed damping force control (when estimation accuracy is low). This dynamic adaptation allows the system to maintain optimal performance across different operating conditions
2Speed
If variable damping force control is maintained during low estimation accuracy, then control responsiveness is preserved, but control correctness deteriorates due to inaccurate state estimation
Solution Approach 1:
The system uses feedback from wheel speed sensors to continuously assess estimation accuracy and adjusts the control mode accordingly. When low estimation accuracy is detected, the system transitions to fixed damping force control to prevent incorrect control actions, while still maintaining control functionality
Solution Approach 2:
The system prepares for potential estimation errors by having a fallback control mode (fixed damping force control) ready to activate. This pre-prepared contingency prevents incorrect control actions before they can occur, ensuring control correctness is maintained even when estimation accuracy deteriorates
Data Source
AI summary
A vehicle control device includes a sensor and a controller. The sensor detects wheel speed. The controller estimates sprung mass state based on detected information in a prescribed frequency range. The controller controls a variable-damping force shock absorber to bring the estimated sprung mass state to a target sprung mass state. The controller estimates wheel rim braking/drive torque acting on a wheel. The controller determines the estimation accuracy of the sprung mass state has deteriorated when a rate of change of a stationary component extracted from components of wheel rim braking/drive torque acting on a wheel is detected to equal or exceed a prescribed value. The controller controls the variable-damping force shock absorber to a more limited extent than when the estimation accuracy has not deteriorated.