Vehicle Control Interface for ADS Brakehold Standstill Coordination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge of safely bringing a vehicle to a standstill during autonomous driving, particularly when the developers of the autonomous driving system and vehicle platform are different, necessitates an appropriate interface to ensure safe coordination between the two systems.
Innovation Solution
An autonomous driving system (ADS) is mounted on a vehicle platform (VP) with an electric parking brake system and a vehicle control interface that includes a processor and memory, providing a standstill status signal to manage brakehold activation and release, ensuring continuous deceleration requests until the vehicle comes to a standstill and subsequent acceleration to maintain the standstill status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the autonomous driving system requests deceleration after the vehicle comes to a standstill, then the vehicle may move backward or forward unintentionally, but if deceleration requests are stopped immediately at standstill, then the vehicle may not maintain the standstill status reliably
Solution Approach 1:
The system continuously monitors the standstill status signal from the vehicle control interface and uses this feedback to adjust deceleration requests. The compute assembly maintains deceleration requests as long as the standstill status signal indicates the vehicle is not yet firmly stopped, and stops requests when the signal confirms reliable standstill, preventing both premature stopping and excessive deceleration after standing.
Solution Approach 2:
The system prepares for potential movement by maintaining deceleration requests slightly beyond the initial standstill detection. This preliminary continued deceleration ensures the vehicle remains firmly stopped and prevents unintentional movement, while the feedback mechanism ensures requests are stopped promptly when standstill is confirmed reliable.
2Adaptability or versatility
If the autonomous driving system and vehicle platform are developed by different developers, then system integration flexibility is improved, but coordination reliability for safe standstill control deteriorates
Solution Approach 1:
The vehicle control interface provides a universal standstill status signal that serves multiple functions: indicating when the vehicle has stopped, confirming reliable standstill status, and triggering appropriate deceleration requests. This multi-functional signal enables reliable coordination between independently developed systems through a standardized interface that handles both information exchange and control coordination.
Solution Approach 2:
The standstill status signal acts as an intermediary between the autonomous driving system and vehicle platform. It translates the complex state of vehicle stopping into a simple, reliable binary indicator that the compute assembly can use to make safe deceleration decisions, enabling reliable coordination without requiring tight integration between independently developed systems.
Data Source
AI summary
A VP includes an EPB system configured to switch between activation and release of brakehold and a VCIB that interfaces between an ADS and a VP. The VCIB is configured to provide a standstill status signal to the ADS. The standstill status signal includes a value applied indicating activation of brakehold and a value released indicating release of brakehold. The ADS includes a compute assembly. When the compute assembly requests the VP to activate brakehold, it requests the VP to decelerate until the standstill status signal switches from the value released to the value applied.