MDPS Steering Control for Rapid Autonomous-to-Manual Switching
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Solution Overview
Problem
The existing motor driven power steering (MDPS) systems face challenges in quickly switching from autonomous driving mode to manual driving mode during sudden steering, requiring a predetermined time regardless of steering torque, leading to reduced control stability and potential abnormal vehicle behavior due to output differences in mode control situations.
Innovation Solution
An apparatus and method that include an MDPS basic logic unit, an autonomous driving steering control unit, a filter unit, and a control unit to determine a final auxiliary command current based on selectively filtered column torque, allowing quick mode switching by varying reference times and weights, and deactivating noise torque filters during sudden steering conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predetermined time is required for mode switching regardless of steering torque, then false cancellation due to noise torque is prevented, but quick response to sudden steering is delayed
Solution Approach 1:
The reference time for judging driver intervention is made variable rather than fixed. The control unit adjusts the reference time based on the magnitude of column torque: when column torque exceeds a threshold value, a shorter reference time is used to enable quick mode switching during sudden steering, while under normal conditions a longer reference time is used to prevent false cancellation due to noise torque.
Solution Approach 2:
The system changes the parameter of reference time based on the operating condition (column torque magnitude). By monitoring column torque and dynamically adjusting the reference time parameter, the system adapts to different driving scenarios, achieving both quick response during emergency steering and reliable noise filtering during normal operation.
2Reliability
If mode switching is delayed during sudden steering, then false cancellation is avoided, but control stability and driver safety are compromised
Solution Approach 1:
The reference time parameter is dynamically changed based on column torque magnitude. When sudden steering is detected (column torque exceeds threshold), the reference time is reduced to enable rapid mode switching, preventing delayed driver control response. This resolves the contradiction between maintaining control stability and avoiding harmful delays.
Solution Approach 2:
The system continuously monitors column torque and uses this feedback to adjust the reference time for mode switching judgment. This closed-loop feedback mechanism ensures that the system responds appropriately to driver input, quickly switching to manual mode when needed while maintaining stability during normal autonomous operation.
3Measurement precision
If noise torque filter is always activated, then accurate torque measurement is achieved, but sudden steering detection is delayed
Solution Approach 1:
The noise torque filter is dynamically controlled rather than always active. The control unit monitors column torque magnitude and temporarily deactivates the noise torque filter when sudden steering is detected (column torque exceeds threshold), allowing rapid detection and response while maintaining accurate torque measurement under normal conditions.
Solution Approach 2:
The system preliminarily identifies sudden steering conditions by monitoring column torque magnitude and proactively adjusts filter activation status. When a sudden steering condition is detected, the filter is temporarily deactivated in advance to prevent detection delays, while maintaining filter activation for accurate measurement during normal operation.
Data Source
AI summary
Provided are an apparatus and a method for controlling a motor driven power steering system. The apparatus may include an MDPS basic logic unit configured to determine a first auxiliary command current in a manual driving mode of a vehicle, an autonomous driving steering control unit configured to determine a second auxiliary command current in an autonomous driving mode, a filter unit configured to filter the column torque so that noise torque is removed, and a control unit configured to control whether to activate the filter unit according to whether a predefined sudden steering condition is satisfied, to determine a driver's steering intervention based on selectively filtered column torque, to determine a final auxiliary command current by applying a weight to the first and second auxiliary command currents, and to control switching from the autonomous driving mode to the manual driving mode.