Steering Control Gain Adjustment for Mode Switching
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Solution Overview
Problem
When switching from automatic steering mode to manual steering mode, drivers experience unusual feelings due to varying steering characteristics and N deviation reductions, leading to inconsistent steering responses.
Innovation Solution
A vehicular steering control device that gradually reduces the control gain only when the driver operates the steering input device, and adjusts the N deviation reduction based on the deviation size and steering operation velocity, ensuring consistent steering characteristics during mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control gain is gradually reduced when switching from automatic steering mode to manual steering mode, then the steering characteristic change is smoothed and driver comfort is improved, but the steering response becomes delayed and less responsive to driver input
Solution Approach 1:
The control gain is dynamically adjusted based on the detected steering operation state. When steering operation is detected, the control gain is maintained at a higher value for responsive steering. When no steering operation is detected, the control gain is gradually reduced to smooth the transition. This dynamic adjustment resolves the contradiction by making the system responsive when needed while maintaining comfort during idle periods.
Solution Approach 2:
The control gain parameter is changed conditionally based on steering operation detection. Instead of a fixed gradual reduction, the parameter changes adaptively: maintained high during steering operations and reduced gradually during non-operations. This parameter change strategy allows the system to achieve both responsive steering and smooth transition characteristics at different times.
2Stability of the object's composition
If the control gain is reduced continuously during mode switching, then the transition is smooth, but the steering characteristic varies at each intermittent steering operation causing unusual feeling
Solution Approach 1:
The control gain reduction is performed periodically only during intervals when no steering operation is detected. When steering operation is detected, the reduction is paused and the gain is maintained. This periodic action pattern ensures that the steering characteristic remains consistent across multiple intermittent steering operations, eliminating the unusual feeling while still achieving smooth transition over time.
Solution Approach 2:
The system continuously monitors the steering operation state and uses this feedback to control the gain reduction process. When steering operation is detected, the feedback signal prevents further gain reduction. This feedback mechanism ensures that the steering characteristic remains stable and consistent during driver operations, resolving the issue of varying characteristics causing unusual feelings.
3Speed
If the control gain is abruptly reduced to 0 when switching modes, then the steering response is immediate and responsive, but the driver experiences unusual feeling due to rapid change in overriding degree
Solution Approach 1:
The control gain reduction is made dynamic and conditional rather than abrupt. The system detects steering operations and adjusts the reduction rate accordingly, pausing reduction during operations and resuming during idle periods. This dynamic approach maintains immediate responsiveness when needed while providing comfort during the overall transition process.
Solution Approach 2:
The control gain parameter changes are made adaptive based on steering operation detection. Instead of a fixed abrupt or continuous reduction, the parameter changes are conditional: maintained during steering operations and reduced gradually during non-operations. This resolves the contradiction by achieving both immediate responsiveness and driver comfort through context-aware parameter adjustment.
Data Source
AI summary
A vehicular steering control device 10 comprises a rudder angle variable device 14 which alters relationship between an operating position of a steering wheel 20 and an operating position of the steering wheel found from a rudder angle of steered wheels 18FL and 18FR, and a rudder angle control device 16 which performs an automatic steering control which controls the rudder angle of the steered wheels by controlling the rudder angle variable device. When a steering mode is switched from an automatic steering mode to a manual steering mode (S150), the rudder angle control device gradually reduces a control gain Klka of the automatic steering mode (S600), and reduces by degrees a size of a deviation between the two operating positions (S400, 500, 800˜1000), only when the steering operation is performed by a driver (S350).