ACC Braking Torque Compensation During Transmission Shift-Down
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Solution Overview
Problem
Existing driver assistance systems experience issues with vehicle pushing during braking and acceleration shocks when shift-down of the transmission occurs during deceleration with adaptive cruise control (ACC) activated, due to differences in vehicle acceleration before and after ACC activation.
Innovation Solution
A driver assistance apparatus and method that utilizes a front sensor and controller to maintain braking torque and compensate for changes in acceleration by determining the gear stage and vehicle speed, adjusting braking torque based on factors like weight and tire radius to prevent vehicle pushing and acceleration shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If shift-down of transmission occurs during deceleration with ACC activated, then vehicle deceleration control is adjusted, but braking torque decreases causing vehicle pushing
Solution Approach 1:
The controller predicts the occurrence of shift-down before it actually happens by monitoring gear stage and vehicle speed conditions. When shift-down is predicted, the controller preemptively adjusts the braking torque compensation value to maintain stable braking torque, preventing vehicle pushing before it occurs.
Solution Approach 2:
The controller continuously monitors gear stage, vehicle speed, and braking torque conditions. When shift-down occurs or is predicted, the system provides feedback by adjusting the braking torque compensation value, creating a closed-loop control system that maintains stable braking performance despite transmission shifts.
2Extent of automation
If ACC activation changes required acceleration from driver operation, then automated cruise control is achieved, but acceleration shock occurs due to difference between actual and required acceleration
Solution Approach 1:
The controller predicts acceleration shock by comparing required acceleration with actual vehicle acceleration before the shock occurs. When prediction indicates impending shock, the controller preemptively adjusts engine torque or braking torque to counteract the harmful acceleration change, preventing the shock from affecting the driver.
3Reliability
If transmission gear stage is monitored to predict shift-down, then braking torque can be maintained, but system complexity increases
Solution Approach 1:
The controller utilizes existing vehicle sensors and control units that are already present in modern vehicles (gear stage sensor, speed sensor, engine control unit). By leveraging these existing components, the system maintains braking torque without requiring additional dedicated hardware, thus avoiding increased system complexity while achieving reliable braking maintenance.
Data Source
AI summary
A driver assistance apparatus includes a front sensor installed in a vehicle and having a field of sensing in front of the vehicle and a controller configured to process data obtained by the front sensor, and the controller is configured to determine whether the vehicle is in a situation in which deceleration is required in response to the processing of the data of the front sensor when adaptive cruise control (ACC) is in an activated state and maintain a braking torque required for the deceleration so that the vehicle is not pushed during braking when the vehicle is in the situation in which the deceleration is required.