Autonomous Vehicle Steering Fallback During Command Loss
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Solution Overview
Problem
Existing steering systems in autonomous vehicles are single fault tolerant, lacking redundancy, and have no human backup, making them unreliable in cases of complete loss of communication with the autonomous driving control system.
Innovation Solution
The steering system continues to maintain the last valid steering control position if communication with the autonomous driving control system is lost for a predetermined duration, and may ignore subsequent control commands if the loss persists beyond a second predetermined duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the steering system relies on continuous communication with the autonomous driving control system, then the system can operate autonomously without human backup, but the system becomes unreliable in cases of complete loss of communication
Solution Approach 1:
The steering system is configured with predetermined fallback behaviors that are established in advance. When communication is lost, the system automatically executes pre-programmed responses such as maintaining the last valid steering position or returning to a neutral position, ensuring reliable operation without human intervention even during complete communication failure
Solution Approach 2:
The system incorporates communication failure as a anticipated hazard and prepares compensatory measures in advance. By programming the steering system to detect communication loss and automatically switch to safe fallback modes, the system cushions against the harmful effect of complete communication failure, maintaining operational reliability
2Stability of the object's composition
If the steering system maintains the last valid steering control position during communication loss, then the wheel orientation remains stable and predictable, but the system may continue operating with potentially outdated control commands
Solution Approach 1:
The steering system continuously monitors communication status with the autonomous driving control system. When communication is lost, the system executes fallback behavior to maintain stable wheel orientation. Upon restoration of communication, the system performs a validity check by comparing the new control command with current operational conditions, ensuring that only valid and appropriate commands are executed, thus resolving the contradiction between stability and command validity
Data Source
AI summary
Aspects of the disclosure relate to controlling a vehicle in an autonomous driving mode. For instance, a control command identifying a steering control position may be received by a steering system of the vehicle from an autonomous driving control system. Orientation of one or more wheels of the vehicle may be controlled according to the steering control position. After receiving the control command, that the steering system has not received a valid control command from the control system for a first predetermined duration may be determined. Based on the determination that the steering system has not received a valid control command from the control system for the first predetermined duration, the orientation of the one or more wheels may be continue to be controlled based on the steering control position.