AEB Braking Control Adjusted for Vehicle Mass Variation
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Solution Overview
Problem
Conventional autonomous emergency braking (AEB) systems in vehicles assume a constant deceleration rate, which can lead to inadequate braking performance when the vehicle's mass varies significantly, such as in tractor-trailers with varying loads.
Innovation Solution
The system adjusts the deceleration value based on the vehicle's mass by determining the mass-adjusted deceleration value and controlling the timing and force of braking commands to optimize braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant predetermined deceleration value is used in AEB systems, then the system is simple to operate and control, but the braking performance becomes inadequate when vehicle mass varies significantly
Solution Approach 1:
The patent applies dynamics by making the deceleration value adjustable based on vehicle mass. The system transitions from a static, fixed deceleration value to a dynamic value that changes according to the actual vehicle mass detected by sensors. This allows the AEB system to adapt to varying loads (bobtail, partially loaded, fully loaded configurations) while maintaining reliable braking performance across all operating conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the deceleration parameter based on vehicle mass. The controller adjusts the deceleration value upward for heavier vehicle masses and downward for lighter masses. This parameter adaptation ensures that the braking force is appropriately scaled to the vehicle's actual mass, resolving the contradiction between operational simplicity and braking reliability.
2Speed
If the predetermined deceleration assumes a lightly loaded vehicle, then the braking response is quick for light loads, but the vehicle cannot stop in sufficient time when heavily loaded
Solution Approach 1:
The system changes the deceleration parameter dynamically based on detected vehicle mass. When the vehicle is lightly loaded, a lower deceleration value is used, enabling quick braking response. When heavily loaded, the system automatically increases the deceleration value to ensure the vehicle can stop within sufficient distance. This parameter adaptation resolves the contradiction between fast braking response for light loads and adequate stopping distance for heavy loads.
3Reliability
If the predetermined deceleration assumes a heavily loaded vehicle, then the stopping distance is sufficient for heavy loads, but the vehicle stops far away from potential collision when lightly loaded
Solution Approach 1:
The system adjusts the deceleration parameter based on actual vehicle mass detection. For heavily loaded vehicles, a higher deceleration value ensures sufficient stopping distance. For lightly loaded vehicles, the system reduces the deceleration value, allowing the vehicle to stop closer to the potential collision point and reducing unnecessary loss of time. This dynamic parameter adjustment resolves the contradiction between adequate stopping distance and minimizing time loss.
4Adaptability or versatility
If a compromise deceleration value is used, then the system works for both light and heavy loads, but braking performance is sacrificed for both conditions
Solution Approach 1:
Rather than using a static compromise deceleration value, the patent implements a dynamic adjustment mechanism that detects vehicle mass and automatically selects the appropriate deceleration value. This dynamic approach maintains optimal braking performance for both light and heavy loads, eliminating the need to sacrifice performance for adaptability. The system achieves both adaptability and high reliability simultaneously through real-time parameter adjustment.
Data Source
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AI summary
An autonomous emergency braking system includes a sensor generating a collision risk signal indicative of an object in a path of travel of the vehicle and a controller. The controller determines whether an indication of a mass of the vehicle is present and, if so, adjusts a default deceleration value corresponding to a predetermined rate of deceleration for the vehicle in response to the mass to obtain a mass-adjusted deceleration value. The controller establishes, responsive to the mass-adjusted deceleration value, successive times for generating first and second braking commands to an engine or brake controller or increasing braking forces for the first and second braking commands configured to cause deceleration of the vehicle at first and second rates of deceleration, the second rate greater than the first. The first and second braking commands are generated responsive to the collision risk signal.