Steering Assist Differential Angle Control for Mode Transition
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Solution Overview
Problem
Existing automatic steering systems cause discomfort to drivers due to differential angle offsets when transitioning from manual to automatic steering modes, leading to unwanted changes in the steering angle and turning angle.
Innovation Solution
A steering assist apparatus that controls the differential angle by determining a target differential angle close to the automatic steering mode's target differential angle during transitions from manual to automatic steering, using a steering input apparatus and a steering drive unit, and maintaining this angle when no input variation is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the differential angle offset is cancelled or reduced when the driver is performing steering operation, then the offset of differential angle is mitigated, but the differential angle changes regardless of the steering operation causing driver discomfort
Solution Approach 1:
The patent applies dynamics by making the differential angle dynamically adjustable based on the steering mode. During automatic steering mode, the differential angle is set to a first value optimized for automatic control, while during manual steering mode, it is set to a second value that provides natural steering feedback to the driver. This dynamic adjustment resolves the contradiction by allowing the system to optimize for offset mitigation in automatic mode while maintaining driver comfort in manual mode.
Solution Approach 2:
The patent changes the parameter of differential angle based on the detected steering mode. When the control unit detects automatic steering mode, it sets the differential angle to a first value; when manual steering mode is detected, it sets the differential angle to a second value. This parameter change approach allows the system to achieve offset mitigation during automatic steering while preventing unwanted differential angle changes during manual steering, thereby maintaining driver comfort.
2Reliability
If the differential angle is adjusted during transition from manual to automatic steering mode, then the offset is reduced, but unwanted changes in steering angle and turning angle occur
Solution Approach 1:
The patent applies preliminary action by detecting the steering mode in advance and setting the appropriate differential angle value before steering operations are performed. The control unit continuously monitors whether the system is in automatic or manual steering mode and pre-sets the differential angle accordingly, preventing unwanted changes in steering angle and turning angle during mode transitions.
Solution Approach 2:
The patent uses feedback by having the control unit continuously detect the current steering mode (automatic or manual) and adjust the differential angle based on this feedback. This closed-loop control ensures that the differential angle is appropriately set for the current operating mode, maintaining stability of steering angle and turning angle while reducing offset during automatic steering transitions.
3Ease of operation
If the differential angle is kept constant during manual steering, then driver comfort is maintained, but offset during automatic steering mode cannot be mitigated
Solution Approach 1:
The patent makes the differential angle dynamic rather than constant, allowing it to take different values based on the steering mode. During manual steering, the differential angle is set to a second value that maintains driver comfort, while during automatic steering, it is set to a first value that enables offset mitigation. This dynamic adaptation resolves the contradiction between maintaining comfort and achieving offset reduction.
Solution Approach 2:
The patent changes the differential angle parameter based on the detected steering mode. The control unit detects whether manual or automatic steering is active and sets the differential angle to the appropriate value (second value for manual, first value for automatic). This parameter change strategy allows the system to maintain driver comfort during manual steering while enabling effective offset mitigation during automatic steering mode.
Data Source
AI summary
A steering assist apparatus is provided with a steering drive unit driving a steering apparatus, a steering control unit executing an automatic steering mode where a steering drive unit is controlled such that a turning angle is determined based on at least either a running state of the vehicle or road information to produce the determined turning angle, and a target differential angle control unit determining a target differential angle. The target differential angle control unit determines the target differential angle to be close to an automatic steering target differential angle used for the automatic steering mode, when input variation through a steering input apparatus is not detected during a transition period from a manual steering mode where the steering apparatus operates in response to the steering angle inputted through the steering input apparatus to the automatic steering mode or during an elapsed period after completing the transition period.