Vehicle Travel Control Device Using Driver Steering Input
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Solution Overview
Problem
Conventional vehicle travel control devices require exterior information acquisition to set and control vehicle trajectories, leading to delays and inefficiencies in steering angle control, especially when lane information is unavailable or incomplete.
Innovation Solution
A vehicle travel control device that calculates and controls the steered angle of steerable wheels based on the driver's steering operation amount and vehicle speed, eliminating the need for exterior information acquisition by using a feed-forward control method to align the vehicle trajectory with a target trajectory without delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exterior information acquisition means (camera, GPS) is used to determine target trajectory and actual trajectory, then vehicle trajectory control can be achieved, but control delay occurs and the system cannot operate when exterior information is unavailable
Solution Approach 1:
The patent calculates the target steered angle in advance based on the driver's steering operation amount and vehicle speed at the decision time point, rather than continuously acquiring and processing exterior information. This preliminary calculation eliminates control delay by preparing the control parameter before it is needed, allowing immediate execution when the control decision is made.
Solution Approach 2:
The patent extracts the essential control parameters (steering operation amount and vehicle speed) from the complex exterior information acquisition system. By focusing only on these critical inputs that directly reflect driver intent and vehicle state, the system eliminates the need for cameras and GPS while maintaining effective trajectory control.
2Reliability
If exterior information acquisition means is required to set target trajectory, then trajectory control can be established, but the system complexity increases and operation is limited when exterior information is unavailable
Solution Approach 1:
The patent removes the exterior information acquisition means (camera, GPS) from the system entirely. Instead, it uses only the driver's steering operation amount and vehicle speed, which are already available through the vehicle's existing steering and speed sensors. This extraction of essential elements simplifies the system while maintaining trajectory control capability.
Solution Approach 2:
The system uses the driver's own steering operations as the basis for trajectory control, eliminating the need for external information sources. The driver's steering input naturally provides the target direction information, and the vehicle's speed provides the motion state information, making the system self-sufficient without cameras or GPS.
3Measurement precision
If feedback control based on actual trajectory is used, then trajectory accuracy can be improved, but control response is delayed until actual trajectory is determined
Solution Approach 1:
The patent calculates the target steered angle in advance based on the driver's steering operation amount and vehicle speed at the decision time point, rather than waiting for actual trajectory data. This preliminary calculation provides immediate control response while maintaining accuracy by basing the calculation on the driver's current steering intent and the vehicle's current speed.
Solution Approach 2:
Instead of using feedback from actual trajectory to determine control actions, the patent inverts the approach by using the driver's steering operation amount (which inherently indicates the desired trajectory) to directly calculate the target steered angle. This inversion eliminates the feedback delay while maintaining control accuracy.
Data Source
AI summary
A travel control device for a vehicle has a steered angle varying device 14 or a by-wire type steering device 96 which modifies a relationship of steered angle of steerable wheels to steering operation amount by a driver. When the control device decides that vehicle trajectory control is to be initiated or renewed, it calculates a target steered angle of the steerable wheels for driving the vehicle along a target trajectory which is required for the vehicle to arrive at a target arrival position in a target traveling direction on the basis of steering operation amount by a driver and vehicle speed at a time point of the decision. The control device controls the steered angle of the steerable wheels according to the target steered angle in feed-forward or feed-back manner.