Vehicle Braking Control During MT Double Depression States
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Solution Overview
Problem
During a braking request by a driver assistance application, such as adaptive cruise control (ACC), a 'double depression state' can occur when the driver unintentionally operates the accelerator pedal, leading to a loss of braking force in manual transmission vehicles (MT vehicles).
Innovation Solution
A control device with a controller that executes braking control by generating a braking force in response to a braking request. The controller releases the braking force if a predetermined condition, such as the operation of the clutch pedal or the shift lever being in neutral, is not satisfied, and maintains the braking force if the condition is met, even when the accelerator pedal is operated during braking control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the braking request is rejected when the accelerator pedal is operated during braking control, then the system responds to the driver's acceleration input, but the braking force is unintentionally released in MT vehicles during gear shifting operations
Solution Approach 1:
The system dynamically adjusts the braking control strategy based on the detected driver operation state. When clutch pedal operation or neutral shift lever position is detected during accelerator operation, the system maintains braking force; otherwise, it releases braking force. This dynamic adaptation resolves the contradiction between responding to acceleration input and maintaining braking force.
Solution Approach 2:
The control device uses clutch pedal operation state and shift lever position as intermediary indicators to distinguish between intentional acceleration and gear shifting operations. These intermediaries provide additional context that prevents false interpretation of accelerator pedal operation, thereby maintaining braking force when needed while still allowing it to be released during genuine acceleration requests.
2Reliability
If the braking force is maintained during accelerator operation in MT vehicles, then unintended braking force loss is prevented, but normal acceleration response is hindered
Solution Approach 1:
The system dynamically switches between maintaining and releasing braking force based on real-time detection of clutch pedal operation and shift lever position. This dynamic control ensures braking force is maintained only during gear shifting operations (when clutch is operated or shift lever is in neutral) while allowing normal acceleration response when these conditions are not met, thus resolving the productivity-reliability contradiction.
Solution Approach 2:
The control system changes the braking force parameter based on the detected state of the clutch pedal and shift lever. When the clutch pedal is operated or the shift lever is in neutral position, the braking force parameter is maintained; otherwise, it is released. This parameter change strategy enables the system to differentiate between gear shifting and normal acceleration operations.
3Measurement precision
If the system detects clutch pedal operation or neutral shift lever position to maintain braking force, then accurate distinction between gear shifting and acceleration is achieved, but system complexity increases
Solution Approach 1:
The control device leverages existing multi-functional sensors (clutch pedal position sensor and shift lever position sensor) that serve multiple purposes in the vehicle control system. By utilizing these existing sensors for the additional function of distinguishing gear shifting from acceleration operations, the system achieves precise detection without adding significant complexity, as the sensors already perform other monitoring functions.
Data Source
AI summary
A control device configured to control motion of a vehicle includes a controller. The controller is configured to execute braking control that generates a braking force for decelerating the vehicle in response to a braking request. The controller is configured to release the braking force by the braking control when a predetermined condition for continuing the braking control is not satisfied, and to maintain the braking force by the braking control when the predetermined condition is satisfied, in a case where an accelerator pedal is operated during execution of the braking control.