Vehicle Motion Control Device for Reducing Longitudinal Jerk
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Solution Overview
Problem
Existing vehicle motion control systems do not adequately consider the relationship between vehicle motion induced by a driver's brake operation and control command output, leading to discomfort for the driver due to unaligned acceleration and deceleration corrections.
Innovation Solution
A vehicle motion control system that includes a control command value calculation unit, longitudinal acceleration estimating unit, longitudinal jerk estimating unit, deviation determination unit, and control command value correction unit to calculate and correct control commands based on the deviation between driver-induced and control-command-induced vehicle motions, ensuring alignment and reducing discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motion control system controls longitudinal acceleration based on driver's accelerator pedal operation, then the driver's intention of accelerating and decelerating is aligned, but the relationship between vehicle motion induced by brake operation and control command is not sufficiently considered, causing driver discomfort
Solution Approach 1:
The control command is segmented into multiple components: a first command value from the motion control algorithm and a second command value for correcting longitudinal acceleration. This segmentation allows independent optimization of each component - the first handles basic motion control while the second specifically addresses driver comfort by compensating for brake-induced longitudinal acceleration changes.
Solution Approach 2:
A correction value is introduced as an intermediary element between the motion control algorithm output and the final control command. This correction value, derived from lateral jerk detection, mediates the interaction between steering-induced lateral motion and longitudinal acceleration, ensuring that brake operations do not create uncomfortable longitudinal motion for the driver.
2Ease of operation
If the system corrects longitudinal acceleration based on lateral jerk, then driver comfort is improved, but the control system becomes more complex with additional sensors and processing
Solution Approach 1:
The lateral jerk detection mechanism serves multiple functions: it detects driver steering input intensity, determines road curvature, and triggers appropriate longitudinal acceleration correction. By making this single detection mechanism multi-functional, the system avoids adding separate sensors or processing units for each function, thereby limiting the increase in system complexity.
Solution Approach 2:
The system changes the parameter being monitored from simple lateral acceleration to lateral jerk (the rate of change of lateral acceleration). This parameter change enables the system to detect dynamic steering inputs more effectively and trigger longitudinal acceleration correction only when necessary, improving driver comfort without requiring continuous complex processing.
3Adaptability or versatility
If the control system integrates multiple motion control algorithms, then functionality is enhanced, but the coordination between different control commands becomes complex and may cause driver discomfort
Solution Approach 1:
Instead of having the motion control algorithm directly output the final control command, the system inverts the traditional control flow by first generating a correction value from lateral jerk detection, then applying this correction to the motion control algorithm output. This inversion ensures that comfort considerations take precedence over pure motion control objectives.
Solution Approach 2:
The system implements feedback by continuously monitoring lateral jerk and using this information to dynamically adjust the longitudinal acceleration command. This feedback loop ensures that the control system adapts to real-time driving conditions and driver inputs, coordinating multiple motion control algorithms smoothly without causing driver discomfort.
Data Source
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AI summary
Disclosed is a vehicle motion control system that can control a vehicle without making a driver feel uncomfortable. The vehicle motion control system includes a control command value calculation unit configured to calculate a control command value for controlling the longitudinal acceleration of a vehicle; a longitudinal acceleration estimating unit configured to estimate the longitudinal acceleration of the vehicle induced by a driver's brake operation; a longitudinal jark estimating unit configured to estimate the longitudinal jark of the vehicle by differentiating the longitudinal acceleration with respect to time; a deviation determination unit configured to determine a deviation between vehicle's motion induced by the driver's brake operation and vehicle's motion induced by a control command using the longitudinal jark and the control command value; and a control command value correction unit configured to correct the control command in accordance with a deviation determination result of the deviation determination unit.