MDPS Mode Transition Dynamics for Autonomous Steering
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Solution Overview
Problem
Autonomous vehicles experience stability issues and a sense of difference during mode transitions from autonomous driving to manual driving, particularly due to output differences in motor-driven power steering (MDPS) control modes, which can lead to passenger discomfort and anxiety.
Innovation Solution
An apparatus and method for controlling MDPS that includes a driving information input unit, a steering angle location control unit, and an MDPS control unit to determine driver intervention in steering by analyzing vehicle speed, steering angles, and column torque, applying weighting to compute compensation outputs, and smoothly transitioning modes based on autonomous driving situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operation mode for MDPS control changes from location control mode to torque control mode when traveling speed changes, then the autonomous vehicle can adapt to different driving conditions, but an output difference occurs in the intermediate process causing passenger discomfort and reduced stability
Solution Approach 1:
The patent applies dynamics by making the transition speed variable rather than fixed. The control system dynamically adjusts the transition speed between location control mode and torque control mode based on the current traveling speed of the autonomous vehicle. This dynamic adjustment prevents abrupt output differences during mode transitions, thereby maintaining stability while preserving adaptability to different driving conditions.
2Speed
If the transition speed between autonomous driving mode and manual mode is increased, then the mode transition responds faster to driver intervention, but the transition becomes less smooth causing a sense of difference
Solution Approach 1:
The patent implements dynamics by making the transition speed adaptive rather than constant. The system automatically adjusts the transition speed based on the detected driver intervention and current driving state. When driver intervention is detected, the transition speed is optimized to balance responsiveness with smoothness, preventing abrupt changes that would cause a sense of difference while still responding timely to driver needs.
3Reliability
If the cutoff frequency of the high-pass filter is increased to improve noise robustness, then command steering angle noise is reduced, but the responsiveness to actual steering inputs decreases
Solution Approach 1:
The patent applies dynamics by making the cutoff frequency variable rather than fixed. The high-pass filter's cutoff frequency is dynamically adjusted based on the current operating conditions and noise characteristics. This dynamic adjustment allows the system to achieve noise robustness when needed while maintaining responsiveness to actual steering inputs, resolving the contradiction between reliability and speed.
Data Source
AI summary
An apparatus may include a driving information input unit for receiving driving information generated while a vehicle travels, a steering angle location control unit for receiving a command steering angle for autonomous driving and a current motor steering angle of a driving motor and outputting an autonomous driving command through location control, and a motor-driven power steering control unit for driving the driving motor based on the autonomous driving command in an autonomous driving mode, determining whether a driver intervenes in steering, based on the driving information during the autonomous driving, computing a driver command according to the driver' steering based on a result of the determination, computing a compensation output between the autonomous driving command and the driver command by applying a weighting according to a steering angular speed, and making a mode transition from the autonomous driving mode to a driver mode while driving the driving motor.