Vehicle Steering Control Ramp-Down for Lane-Keeping Exit Timing
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Solution Overview
Problem
Current travel control devices for vehicles, such as lane departure prevention and lane keeping systems, cannot adjust the rate of decrease of automatic steering control quantities based on the magnitude relationship between target and actual control quantities when control ending conditions are met, leading to inefficient termination of control operations.
Innovation Solution
A travel control device that includes an object information acquisition system, automatic steering, and an electronic control unit to calculate and adjust the target correction quantity of the steering angle based on the magnitude relationship between the target and actual control quantities, allowing for variable rate of decrease to optimize control ending conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a preset rate of decrease is used for the control quantity of automatic steering when control ending conditions are satisfied, then the control quantity decreases gradually, but the control quantity cannot be gradually decreased according to the magnitude relationship between the target control quantity and the actual control quantity
Solution Approach 1:
The patent applies dynamics by making the rate of decrease of the control quantity variable rather than fixed. The control quantity decreases at a first degree when the actual control quantity is greater than the target control quantity, and at a second degree when the target control quantity is greater than the actual control quantity. This dynamic adjustment allows the system to adapt the control ending process to different operational situations, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent changes the parameter of the rate of decrease based on the magnitude relationship between target and actual control quantities. By switching between different degrees of decrease (first degree vs. second degree), the system optimizes the control ending behavior for different scenarios without requiring complex additional mechanisms, thus improving adaptability while managing complexity.
2Loss of time
If the control quantity decreases at a high rate, then the control ends quickly when not necessary, but the control may end too early when continuous control is needed
Solution Approach 1:
The patent uses feedback by continuously monitoring the magnitude relationship between the target control quantity and the actual control quantity. Based on this feedback, the system determines whether to apply a first degree or second degree of decrease. This feedback mechanism ensures that the control quantity decreases at the appropriate rate, preventing both premature termination and unnecessarily prolonged control, thus resolving the contradiction between time loss and reliability.
Solution Approach 2:
The system dynamically adjusts the decrease rate based on real-time conditions. When the actual control quantity exceeds the target, a higher decrease rate is applied to end control quickly. When the target exceeds the actual, a lower decrease rate is applied to maintain control longer. This dynamic response optimizes both the speed and reliability of control termination.
Data Source
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Figure 3A~3B
AI summary
A travel control device (100) for a vehicle (102) includes an object information acquisition device (16), an automatic steering device (46), and an electronic control unit (10). The electronic control unit (10) is configured to gradually decrease a target correction quantity (Δθt) of a steering angle when the electronic control unit (10) determines that travel control needs to be ended. The electronic control unit (10) is configured to change a degree of decrease of the target correction quantity (Δθt) to different degrees based on a magnitude relationship between a target control quantity (θt) and an actual control quantity (θ) closest to a time point at which it is determined that the travel control needs to be ended.