Vehicle Control Device Torque Redistribution for Slip Suppression
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Solution Overview
Problem
Existing vehicle control systems face challenges in suppressing wheel slip and motor/tire vibrations, leading to degraded drivability when driving multiple wheels independently, as they rely on absolute angular acceleration for slip determination and high-gain feedback control, which results in inadequate torque transfer and increased vibrations.
Innovation Solution
A vehicle control device and method that uses wheel speed sensors and motor rotation speed sensors to set a base rotation speed, perform slip determination, and redistribute torque from slipping to non-slipping wheels, ensuring target rotation speeds are maintained, thereby reducing motor and tire vibrations and enhancing drivability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-gain feedback control is used to increase torque transfer response, then the response speed improves, but motor and tire vibrations increase significantly
Solution Approach 1:
The control gain is made dynamic by adjusting it based on wheel slip conditions. When slip is detected, the gain is increased to improve response; when no slip occurs, the gain is reduced to minimize vibrations. This dynamic adjustment resolves the contradiction between response speed and vibration suppression.
Solution Approach 2:
The control parameters (gain values) are changed based on the operating conditions. The system switches between different gain settings depending on whether wheel slip is detected, allowing optimal performance across different conditions while avoiding the harmful effects of consistently high gain.
2Reliability
If torque is redistributed to non-slip wheels to suppress slip, then slip suppression improves, but torque distribution stability deteriorates due to vibration
Solution Approach 1:
The system continuously monitors wheel rotation speeds and detects slip conditions, then adjusts torque distribution accordingly. This feedback mechanism ensures that torque is redistributed only when necessary (when slip is detected), maintaining stability during normal operation while achieving effective slip suppression when needed.
Solution Approach 2:
The torque distribution strategy is made dynamic, switching between different distribution patterns based on real-time slip detection. This allows the system to maintain stable torque distribution during normal conditions while achieving effective slip suppression when slip occurs, resolving the contradiction between slip suppression and stability.
3Ease of operation
If absolute angular acceleration is used for slip determination, then detection simplicity improves, but drivability degrades due to torque vibration
Solution Approach 1:
The system replaces simple angular acceleration-based detection with a more sophisticated wheel rotation speed comparison method. By comparing the rotation speeds of multiple wheels and identifying discrepancies, the system achieves more accurate slip detection without the vibrations caused by abrupt torque changes from simple acceleration-based control.
Data Source
AI summary
A vehicle control device includes motors that respectively drive front and rear, left and right wheels independently, wheel speed sensors that detect rotation speeds of the respective wheels, motor rotation speed sensors that detect rotation speeds of the motors corresponding to the respective wheels, a slip determination module that sets, as a base rotation speed, a lowest rotation speed, and performs slip determination on each wheel on the basis of the base rotation speed and the rotation speeds of the motors, a rotation speed control module that performs torque down, and calculates requested torques of the motors from redistributed torques, and a redistribution control module that redistributes a torque down amount of the slipping wheel to a non-slipping wheel to calculate the redistributed torques.