Automated Vehicle Emergency Trajectory Control for Fault-Tolerant Stopping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automated driving systems at SAE Level 4 require fault-tolerant designs to ensure safe operation without a driver, but current methods are costly and complex, particularly in ensuring the vehicle can safely stop after a fault occurs.
Innovation Solution
A method involving dual control units for each actuator, with one unit transmitting regular commands and the other storing emergency commands, ensuring the vehicle can safely stop with predefined deceleration, and using separate bus systems for command transmission to enhance fault tolerance and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant data transmission with parallel transmitters and communication buses is implemented to ensure fault tolerance, then system reliability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The communication system is segmented into two independent channels: a first communication bus for transmitting control commands during normal operation, and a second communication bus for transmitting emergency control commands. This segmentation allows each bus to be simpler while collectively providing fault tolerance, as one bus can fail without compromising the entire system.
Solution Approach 2:
The emergency control commands are prepared and transmitted in advance via the second communication bus before any fault occurs. The control unit stores these pre-calculated emergency commands, so when a fault is detected on the first bus, the system can immediately switch to executing emergency commands without delay for recalculation, ensuring continuous safe operation.
2Reliability
If multiple control units with full emergency functionality are implemented, then fault tolerance is improved, but the number of control commands to be transmitted increases
Solution Approach 1:
Different levels of control functionality are assigned to different control units based on their role. The first control unit handles normal trajectory control commands, while the second control unit is specifically dedicated to emergency trajectory control commands. This local differentiation optimizes the distribution of computational tasks and reduces the total number of commands each unit must manage.
Solution Approach 2:
The emergency control commands include only the essential subset of control actions needed for safe stopping (primarily steering and basic brake control), rather than complete control functionality. This partial action approach provides sufficient emergency capability while minimizing the number of commands that must be transmitted and stored.
3Manufacturing precision
If complete control commands for all actuators are transmitted continuously, then control precision is improved, but data transmission load increases
Solution Approach 1:
The control command transmission system extracts and separates normal control commands from emergency control commands into different communication channels. Additionally, the emergency commands contain only the critical subset of control actions necessary for safe stopping, extracting the essential safety functionality from the complete control set, thereby reducing overall data transmission requirements while maintaining necessary control precision.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for the automated driving of a motor vehicle, by means of at least one control device (1) for calculating a trajectory, wherein control commands for actuators (9-11) for setting longitudinal and lateral guidance of the motor vehicle are calculated for the trajectory and are implemented by the actuators (9-11), wherein the control commands are updated at fixed points in time, wherein at each point in time a current emergency trajectory for bringing the motor vehicle to a standstill is calculated, wherein a set of control commands for actuators (9) for setting at least the lateral guidance are calculated for the emergency trajectory and, in the absence of the control commands for the trajectory, are automatically implemented by the actuators (9) for the emergency trajectory, and also relates to an automated motor vehicle.