Travel Control Device Steering Torque Gain Transition
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Solution Overview
Problem
Conventional systems that switch from manual to automatic steering in vehicles often cause abrupt steering control, leading to discomfort for drivers due to sudden changes in steering control amounts.
Innovation Solution
A travel control method and device that adjust the steering torque gain over time when switching from manual to automatic driving mode, gradually increasing it to match the steering-angle target value, thereby reducing abruptness and discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a normal control amount is applied to the steering-force transmission system immediately after switching from manual steering to automatic steering, then the steering control responds quickly to the steering-angle target value, but the steering control starts abruptly causing discomfort to the driver
Solution Approach 1:
The patent applies dynamics by making the gain value time-dependent. The gain for multiplying the steering-angle target value changes dynamically based on elapsed time after mode switching. Initially, the gain is set to a smaller value to prevent abrupt steering, then gradually increased to the normal value. This dynamic adjustment allows the system to adapt its response characteristics over time, resolving the contradiction between quick response and driver comfort.
Solution Approach 2:
The patent implements preliminary action by pre-setting a smaller gain value immediately after switching from manual to automatic steering mode. This preliminary adjustment of the control parameter (gain) before reaching the normal operating state prevents the harmful abrupt steering effect from occurring in the first place, while still maintaining the capability for quick response as time progresses.
2Object-affected harmful factors
If the gain is increased according to elapsed time from switching to automatic driving mode, then driver discomfort is reduced during transition, but the control response becomes initially slower
Solution Approach 1:
The system dynamically adjusts the gain value based on elapsed time, creating a time-varying control response. The gain transitions from a smaller initial value to a larger normal value, optimizing the balance between comfort and response speed at different stages of the transition period.
Solution Approach 2:
The control system employs periodic adjustment of the gain parameter over time. The gain is not statically set but evolves through defined time periods, with different gain values applied during different phases of the transition from manual to automatic steering mode.
Data Source
AI summary
A travel control method controls travel of an own vehicle to locate a lateral position of the own vehicle at a predetermined position with respect to a lane marker of a lane in which the own vehicle is traveling or with respect to a preceding vehicle, and reduces a control amount on travel from when control on the travel of the own vehicle is started until a predetermined time passes to be smaller than a control amount on the travel after the predetermined time has passed.