Autonomous Vehicle Stop Control With Brake Hold Confirmation
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Solution Overview
Problem
Current autonomous driving systems lack an effective method to maintain a vehicle in a stationary state after receiving a command to stop, leading to potential instability and inappropriate brake hold control.
Innovation Solution
The implementation of a vehicle control system that sends a first command for deceleration and a second command to maintain stationary, using signals for longitudinal velocity and standstill status to ensure the vehicle remains stationary by continuously requesting deceleration until the standstill signal is confirmed, and utilizing an electric parking brake for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the autonomous driving system continuously issues deceleration commands after the vehicle stops, then the vehicle can be maintained stationary, but this may cause inappropriate brake hold control and system instability
Solution Approach 1:
The system issues a preliminary standstill command before the vehicle actually stops (when longitudinal velocity reaches 0 km/h or a prescribed velocity or less). This preliminary action prepares the brake hold control in advance, ensuring smooth transition to stationary maintenance without requiring continuous deceleration commands after stopping.
Solution Approach 2:
The system monitors the standstill status signal to determine when brake hold control has been successfully established. Once the standstill status indicates that brake hold control is active, the system stops issuing deceleration commands, preventing inappropriate continuous braking while maintaining reliable stationary status.
2Reliability
If the autonomous driving system issues a standstill command before the vehicle stops, then brake hold control can be established, but the timing and coordination with deceleration commands becomes complex
Solution Approach 1:
The system replaces complex mechanical coordination of multiple commands with a simplified signal-based approach. The standstill command is automatically triggered when the longitudinal velocity signal indicates 0 km/h or a prescribed velocity or less, eliminating the need for manual timing coordination and simplifying the control operation.
3Device complexity
If the vehicle platform receives only deceleration commands without a dedicated standstill command, then the control system remains simple, but the vehicle cannot be reliably maintained stationary after stopping
Solution Approach 1:
The control system is segmented into two distinct command types: deceleration commands for stopping the vehicle and standstill commands for maintaining stationary status. This segmentation allows each command to have a specific function, with the standstill command specifically activating brake hold control to reliably maintain the vehicle in a stationary state without adding significant overall system complexity.
Data Source
AI summary
A vehicle comprises an autonomous driving system and a vehicle platform that controls the vehicle in response to a command received from the autonomous driving system. In the present vehicle, when the autonomous driving system issues a first command to request the vehicle platform to provide deceleration to stop the vehicle and a first signal indicates 0 km/h or a prescribed velocity or less, the autonomous driving system issues a second command to request the vehicle platform to maintain stationary. And after brake hold control is finished, a second signal indicates standstill. Until the second signal indicates standstill, the first command continues to request the vehicle platform to provide deceleration.