Safety monitoring method and system for autonomous vehicle, and motion control system
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Solution Overview
Problem
Conventional safety monitoring schemes for autonomous vehicles are too general and simple, failing to effectively adapt to different operating conditions and vehicle statuses, leading to potential safety issues such as sudden turns or accelerations due to erroneous sensor inputs.
Innovation Solution
A safety monitoring method that includes real-time monitoring of steering wheel angle and target acceleration, establishing thresholds based on vehicle kinematics and parameters, and limiting these values when exceeding predetermined thresholds to ensure safe lateral and longitudinal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional safety monitoring schemes directly apply fixed limits to output control amounts, then the purpose of monitoring is achieved to some extent, but the scheme is too general and simple to adapt to different operating conditions and changing vehicle status
Solution Approach 1:
The patent applies dynamics by making the safety monitoring thresholds dynamic rather than fixed. The system establishes correspondence relationships among lateral acceleration, longitudinal vehicle speed, and steering wheel angle, and among target acceleration and vehicle speed. These correspondence relationships allow the thresholds to adapt automatically to different operating conditions and vehicle statuses, resolving the contradiction between maintaining safety monitoring effectiveness and adapting to varying conditions.
2Reliability
If no safety monitoring function is added to the motion control module, then the system operates simply, but sensor failures or abnormal signals cause erroneous calculations and incorrect output leading to unsafe vehicle maneuvers
Solution Approach 1:
The patent introduces a safety monitoring module as an intermediary between the motion control module and the vehicle actuating mechanisms. This intermediary module receives control amounts from the motion control module, limits them according to established correspondence relationships, and outputs safe control amounts. This approach ensures vehicle control safety while adding only the necessary complexity of a dedicated monitoring layer.
Solution Approach 2:
The patent applies preliminary action by establishing correspondence relationships and determining thresholds in advance before actual vehicle operation. The system pre-defines the relationships among lateral acceleration, vehicle speed, and steering wheel angle, as well as among target acceleration and vehicle speed. When sensor failures or abnormal signals occur, these pre-established relationships enable the system to automatically identify and limit erroneous control amounts, preventing unsafe maneuvers without requiring complex real-time analysis.
3Ease of manufacture
If fixed thresholds are applied to control amounts, then implementation is simple, but the control system becomes restricted under certain operating conditions and cannot achieve effective safety monitoring
Solution Approach 1:
The patent applies parameter changes by transforming fixed thresholds into dynamic thresholds based on correspondence relationships. Instead of using fixed limits for steering wheel angle and target acceleration, the system uses relationships that incorporate vehicle speed, lateral acceleration, and operating conditions. This allows the thresholds to change parameters dynamically while maintaining implementation feasibility through pre-established correspondence relationships.
Data Source
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AI summary
A safety monitoring method and system for an autonomous vehicle. Said method comprises: a lateral control safety monitoring step, establishing a correlation between a lateral acceleration of a vehicle, a longitudinal vehicle speed and a steering wheel steering angle, acquiring a maximum steering wheel steering angle corresponding to a given maximum lateral acceleration at different vehicle speeds, taking the maximum steering wheel steering angle as a steering angle threshold, determining whether the steering wheel steering angle is greater than the steering angle threshold, and if so, limiting the steering wheel steering angle within the steering angle threshold, otherwise, normally outputting; and a longitudinal control safety monitoring step, with regard to different longitudinal control states, acquiring an acceleration threshold corresponding to a given maximum target acceleration at different vehicle speeds, and determining whether the target acceleration is greater than the acceleration threshold, and if so, limiting the target acceleration within the acceleration threshold, otherwise, normally outputting. The safety monitoring method and system for an autonomous vehicle design a safety monitoring policy for an automated driving system from the perspective of lateral control or longitudinal control respectively, so that a more integrated design is achieved.