Automated Vehicle Safety Arrangement for Confidence-Based Braking
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Solution Overview
Problem
Fully automated vehicles face challenges in detecting objects at longer ranges due to decreased sensor capabilities, leading to potential late and harsh braking, which increases system cost and complexity, and compromises safety and comfort.
Innovation Solution
A safety arrangement that uses forward-looking detection systems and a control unit to apply a predetermined limited amount of braking until high confidence in object detection is achieved, balancing occupant comfort and safety, utilizing existing sensors and optimizing braking profiles through an optimal control problem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If sensor systems are used to detect objects at longer ranges, then detection distance is improved, but measurement precision deteriorates due to decreased sensor capabilities
Solution Approach 1:
The system applies preliminary limited braking when an object is detected with low confidence, before full braking is triggered. This preliminary action allows the vehicle to slow down gradually, giving the sensor system more time to confirm or refute the object's presence, thereby improving measurement precision without sacrificing detection distance capability
Solution Approach 2:
The patent introduces a cushioning braking phase before full braking. This intermediate braking level acts as a buffer that reduces the harshness of eventual full braking while maintaining safety. The cushioning phase allows time for sensor confirmation, improving object classification capability at long ranges by preventing premature full braking decisions
2Reliability
If full braking is applied immediately upon object detection, then safety is improved, but occupant comfort deteriorates due to late and harsh braking
Solution Approach 1:
The braking force is made dynamic rather than static. The system transitions from no braking to limited braking to full braking based on the evolving confidence level of object detection. This dynamic approach maintains safety by ensuring full braking is applied when confidence is high, while improving comfort by using gentler limited braking during the confidence-building phase
Solution Approach 2:
A cushioning braking phase is introduced before full braking. This preliminary limited braking softens the overall braking experience for occupants while still maintaining safety. The cushioning effect reduces the harshness of the braking event, improving ease of operation without compromising the reliability of collision avoidance
3Measurement precision
If more sophisticated sensors are used to improve long range detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses its existing sensor capabilities to serve multiple functions. By implementing a confidence-based braking system, the existing sensors are made to work more effectively at long ranges through temporal integration and confidence accumulation, rather than requiring more sophisticated hardware. This self-service approach improves measurement precision without increasing device complexity
Solution Approach 2:
The system changes operational parameters (braking force levels, confidence thresholds, time windows) to extract more performance from existing sensors. By adjusting these parameters, the system achieves improved long-range object classification capability using current sensor technology, avoiding the need for more expensive and complex sensor systems
Data Source
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AI summary
Embodiments herein relate to a safety arrangement (1) and method for controlling automatic travel of a fully automated vehicle (2). One or more forward-looking detection systems (3) are provided for detecting objects (4) in a future path of the vehicle (2). A control unit (5) is arranged to determine a detection confidence for the detected objects (4). The control unit (5) is further operable to, upon low confidence for existence of a detected object (4), control a brake system (6) of the vehicle (2) to apply a predetermined limited amount of braking until high confidence is obtained for existence or non-existence of the previously detected object (4). Thereafter the control unit (5) is further operable to apply full braking if high confidence is obtained for existence of the previously detected object (4) and to discontinue braking if high confidence is obtained for non-existence of the previously detected object (4).